photorelease of caged alcohols from artificial
TRANSCRIPT
PHOTORELEASE OF CAGED ALCOHOLS FROM ARTIFICIAL METALLOENZYMES
By
ERIC S. OSHIGE
A Thesis Submitted to the Graduate Faculty of
WAKE FOREST UNIVERSITY
in Partial Fulfillment of the Requirements
for the Degree of
MASTER OF SCIENCE
in the Department of Chemistry
May 2007
Winston-Salem, North Carolina
Approved By:
Paul B. Jones, Ph.D., Advisor ______________________________________
Examining Committee:
S. Bruce King, Ph.D. ______________________________________
Willie L. Hinze, Ph.D. ______________________________________
ii
ACKNOWLEDGMENTS
If during my undergraduate career at the University of South Carolina-
Spartanburg, someone had told me that I would complete a graduate degree in organic
chemistry, I would have likely been in disbelief. See, I enjoyed chemistry but did not
“get” the whole organic field. I have since learned that it is important to look at a topic
(such as the field of your likely future career) from more than one viewpoint. My two
plus years here in Winston-Salem have been quite good. I can’t really complain because
there is actually nothing to complain about. Graduate school is free, I have less than a 2
mile commute (lunch at home every day), and so on. There have been many, many
challenges along the way, but the pain does seem to be numbed in hindsight.
I owe thanks to many people for shaping and supporting me along the way. Mom
and Dad, thanks for making me do my homework before playtime. Dr. Chris Bender (my
undergrad advisor) really got me excited about and involved in chemistry beyond the
classroom. With his help, I landed a sweet internship at a company called Metal-Chem,
Inc., where I got a real dose of industry. I learned that some chemists prefer not to use
the metric system (mL, g, L, etc.), rather hundreds of pounds and gallons! Dr. John D.
Anderson was patient enough to hire a recently graduated BS chemist into his lab at
Milliken Chemical and mold him into a synthetic organic chemist.
Working in the Paul Jones lab has been an excellent experience. Thanks to Paul
for putting me on a cool project and for being a great advisor. I feel like I have become a
better scientist, in mind and in the lab. Thanks to all the past and present Jones group
members for helpful discussions, including those pertaining to chemistry as well as those
iii
about just whatever, and Dr. Anne Glenn of Guilford College, my virtual second advisor.
I owe many thanks to Dr. Marcus Wright for support with NMR and discussions about
the greater Spartanburg, SC and Shelby, NC areas, and to Dr. Cynthia Day for X-ray
crystallographic analysis. Thanks also to Dr. Suzanne Tobey for sharing synthetic
knowledge and for help with the binding titrations and to Dr. Uli Bierbach for sharing
insight on the “complex” field of coordination chemistry.
On the home front, I thank my wonderful wife, Becca, for supporting me each and
every day and listening to me talk about my work. I also thank Peppy, the amazing little
dog that has kept my lap warm for two years as I sat at this coffee table doing school
work, including this thesis (and including this paragraph). I do regret that I never
finished training her to run the rotovap for me.
I will close my introduction with one thought: as of late 2006, I do not know of
any Oshige Reagent in the literature. I hope that I might be the first to report it.
iv
TABLE OF CONTENTS
Page
LIST OF TABLES vii
LIST OF FIGURES viii
ABSTRACT xi
INTRODUCTION 1
Metal and multidentate ligand binding 1
Lewis acid catalyzed hydrolysis 3
Lewis acid catalysis in stereoselective Aldol additions 4
Metal activated hydrolysis of amino acid methyl esters 5
Metal ion catalysis in vivo 6
Carbonic Anhydrase 7
Synthetic metalloenzymes 8
Photochemical isomerization of alkenes 10
Cinnamate ester deacylation photochemistry 12
Photoactivated artificial metalloenzymes 14
References 15
RESULTS AND DISCUSSION 17
Background 17
Mono-substituted 1,10-phenanthroline ligands 18
Photochemistry of ligand (3)-Zn(II) complex 19
Photochemistry of ligand (4)-Zn(II) complex 20
v
Quantifying the hydrolysis efficiency 21
Fast exchange at the metal center 23
Pyridine ligands 24
Photochemistry of ligand (8)-Zn(II) complex 25
Photochemistry of ligand (11) and an array of metals 27
Effect of buffered aqueous media 29
Symmetrical di-substituted 1,10-phenanthroline ligand 31
Pyridine-phenanthroline ligand 35
Evaluation of an array of esters 38
UV-visible spectra 41
Long wavelength absorption band of Cu(II) complex 43
Photoisomerization of ligand (18)-Zn(II) complex 44
Chirality of the Zn(II) complex 45
Analytical methods for evaluation of the hydrolysis 49
Photochemistry of ligand (18) and an array of metals 49
Evaluation of ligand (18)-Zn(II) complex by 1HNMR 50
Evaluation of ligand (18)-Cu(II) complex by gas chromatography 53
Dark control experiments 54
Preparative scale experiments of Zn(II) and Cu(II) complexes 55
UV-vis binding titrations 58
Burst hydrolysis 60
vi
Effect of pyridine additive 61
Evaluation of an amide 64
Conclusion 69
References 70
EXPERIMENTAL 71
General 71
Mono-substituted 1,10-phenanthroline ligands 72
General procedure for yield determination by gas chromatography 75
Pyridine ligands 75
Symmetrical di-substituted 1,10-phenanthroline ligand 80
Pyridine-phenanthroline hybrid ligands 82
General procedure for the prep scale photolysis with Bn ester ligand 87
UV-Vis binding titration procedure 94
References 97
APPENDIX A: X-ray crystallography data 98
APPENDIX B: UV-Visible spectra 129
SCHOLASTIC VITA 136
vii
LIST OF TABLES
Table # Title Page
1 Selected nitrogen-donor ligands 1
2 Selected hydrolytic enzymes and corresponding metals 6
3 Photolysis of Zn(II)-ligand (8) complex 26
4 Ester hydrolysis with an array of metals 28
5 Effect of buffer on hydrolysis efficiency 30
6 Photoisomerization of the di-alkene 33
7 UV-Vis data for benzyl ester ligand (18) and complexes 42
8 Effect of metal on hydrolysis analyzed by GC 50
9 Prep scale isolated yield results 57
10 UV-Vis data for benzyl amide ligand (28) and complexes 66
viii
LIST OF FIGURES
Fig # Title Page
1 Examples of multidentate ligand-metal complexes 2
2 Lewis acid activation at the carbonyl 3
3 Metal-activated H2O as the nucleophile 3
4 Stereoselective Aldol catalysis 4
5 Metal-catalyzed hydrolysis of an amino acid ester 5
6 Human carbonic anhydrase active site 7
7 Metal-catalyzed mechanism of carbonic anhydrase 8
8 RNA hydrolysis mechanism and synthetic metallonucleases 9
9 Synthetic metalloprotease designed to cleave dipeptides 10
10 Photochemical isomerization of an alkene 10
11 Alkene energy surface diagram 12
12 Cinnamate ester deacylation photochemistry 13
13 General photoactivated metalloenzyme scheme 18
14 Synthesis of the 1,10-phenanthroline ligands (3) and (4) 19
15 1HNMR trace of preliminary photolysis and generation of MeOH 20
16 Benzyl ester photolysis 1HNMR traces 21
17 Evaluation of the extent of ester hydrolysis by GC 22
18 UV-Visible spectrum of ligand (4)-Cu(II) complex 23
19 1HNMR traces showing the effect of Cl- on the complex 24
20 Synthesis of ligand (8) 25
21 Synthesis of ligand (11) 26
22 Proposed ligand-metal complex equilibrium 27
23 Water-soluble metal complexes with ligand (11) 28
24 UV-Visible absorption spectrum of Cu(II)-ligand (11) 29
complex in MeOH
25 Long term ester hydrolysis in the dark as a function 31
of light exposure
ix
26 Synthesis of the symmetrical phen ligand 32
27 Proof-of-principle experiment scheme 33
28 1HNMR trace showing EtOH CH2 and CH3 signals 34
29 Proposed structure of the di-cis Zn(II) complex 34
30 Synthesis of ligands (18) and (19) 35
31 Comparison of the two routes to the aldehyde 36
32 Core compound strategy 37
33 Array of pyr-phen ligand esters 38
34 Preparation of analogs by bromide alkylation 39
35 Preparation of analogs by Horner-Emmons olefination 39
36 Preparation of benzyl diethylphosphonoacetate (17) 40
37 Preparation of the menthyl Horner-Emmons reagent (25) 40
38 UV-Visible spectrum of benzyl ester ligand (18) in MeOH 41
39 UV-Visible spectrum of benzyl ester-Zn(II) complex in MeOH 41
40 UV-Visible spectrum of benzyl ester-Cu(II) complex in MeOH 42
41 731 nm absorption band of benzyl ester copper complex in H2O 43
42 a) 1HNMR trace of benzyl CH2 during photoisomerization 44
b) Photostationary state determination 45
43 1HNMR trace of trans benzyl CH2 Zn(II) complex 46
44 Chiral trans Zn(II) complex 46
45 Molecular model of the isomerized cis Zn(II) complex 47
Monohydrate
46 HMQC of benzyl ester (18)-Zn(II) complex 48
47 Zn(II) complex hydrolysis monitored by 1HNMR 51
48 Crude NMR yield of BnOH with varied light exposure 52
49 Effect of light exposure on hydrolysis over time 53
50 Cu(II) complex hydrolysis monitored by GC 54
51 Cu(II) complexes after irradiation 55
52 General scheme for optimized photochemistry and 56
Hydrolysis
x
53 UV-Vis binding titration curve for the benzyl 59
ester-Cu(II) complex
54 UV-Vis binding titration results (ligand/metal ratio) 60
55 Proposed hydrolysis scheme 60
56 Burst hydrolysis as a function of Cu(II) 61
57 Proposed effect of pyridine additive 62
58 Effect of pyridine additive on ester hydrolysis 63
59 Preparation of the benzyl amide Horner-Emmons reagent 64
60 Synthesis of the benzyl amide ligand 64
61 UV-Vis spectrum of benzyl amide ligand (18) in MeOH 65
62 UV-Vis spectrum of benzyl amide ligand-Zn(II) complex 65
63 UV-Vis spectrum of benzyl amide ligand-Cu(II) complex 66
64 Photoisomerization of ligand (28)-Zn(II) complex 67
65 Scheme for the prep scale benzyl amide-Cu(II) photolysis 69
xi
ABSTRACT
PHOTORELEASE OF CAGED ALCOHOLS FROM ARTIFICIAL METALLOENZYMES
Nature frequently employs metalloenzymes to catalyze biological reactions. In
the literature there is precedent for artificial metalloenzymes that serve to selectively
cleave coordinated peptide and ester linkages. These systems take advantage of metal-
ligand coordination and activation of a carbonyl functional group, resulting in hydrolysis.
This project aims to hydrolyze a caged alcohol or amide with a photoactivated metal-
ligand complex. Hydrolysis of the caged molecule is dependent upon metal-ligand
complex formation and stoichiometry, photochemical isomerization of an alkene, Lewis
acid activation of a carbonyl species, and nucleophilic attack by metal-bound H2O. The
photoisomerization from trans to cis is driven to completion by the coordination of the
latter to the metal. The ester hydrolysis is most efficient when the ligand to metal ratio is
1:1. Several ligand systems were synthesized with these factors in mind. The synthesis,
characterization, and investigation of these systems as well as possible applications are
discussed.
1
INTRODUCTION
Metal and multidentate ligand binding
A coordinate covalent bond occurs when an electron donor provides the electrons
to be shared with an electron acceptor. Once formed, however, the adduct bond is not
distinguishable from a covalent bond. It is common for such bonding to occur between a
ligand (or multiple ligands) and a cationic metal. The ligand acts as a Lewis base and the
metal acts as a Lewis acid. A multidentate ligand is capable of providing two or more
coordinate covalent bonds. Nitrogen donor ligands have been reported to be effective in
cationic metal binding. Selected examples of nitrogen monodentate and multidentate
ligands are listed in Table 1, while several metal-ligand complexes are listed in Figure 1.
Table 1. Selected nitrogen-donor ligands.1 ligand structure
pyridine
ethylenediamine
bipyridine
1,10-phenanthroline
ammoniaNH
HH
N
H2NNH2
N N
N N
2
NNN
N NZn2+
N N
N NRu2+
N
N
N
N
Co2+O
O N
N
O
O
O
O
O
O
Cu2+O O
N N
O O
a) b)
c) d)
HH
HH
HH
Figure 1. Examples of multidentate ligand metal complexes: a) polypyridyl Zn(II) ligand,2 b) multidentate ligand for Ru(II),3 c) Co(II)-EDTA complex,4 d) Cu(II)-glycine complex.4
A multidentate ligand complex (chelate) is more thermodynamically stable than
the existence of each component separately in solution which is due to the chelate effect.1
The word chelate comes from the Greek, meaning “claw.” Chelation forms a ring or
multiple rings incorporating the metal.1 The sum of the multiple coordinate covalent
bonds binding the metal is greater than that of one bond. Multidentate binding is
energetically advantageous as compared to monodentate binding. After the first binding
interaction, the subsequent ones are oriented in such a fashion that less energy is required,
giving the system a free energy advantage over a monodentate system.5
3
Lewis acid catalyzed hydrolysis
Esters can undergo hydrolytic cleavage to the corresponding carboxylic acid and
alcohol with either catalytic acid or base. Cleavage of the ester linkage can also be
achieved with a suitable Lewis acid (electron pair acceptor). As depicted in Figures 2
and 3, there are two possible mechanisms for Lewis acid catalyzed ester hydrolysis. In
Figure 2, the electrophile accepts a pair of electrons from the carbonyl, making its carbon
more electropositive. This in turn makes the carbonyl more susceptible to nucleophilic
attack by water and R’OH leaves. In Figure 3, H+ is lost after H2O binds to the metal.
This nucleophilic -OH then cleaves the ester by the standard basic hydrolysis mechanism.
This reaction can be applied to amide (RCONHR’) linkages as well.
Figure 2. Lewis acid activation at the carbonyl.
R
O
OR'M+
R
O
OR' + R'OHOH OH
R
O
OOHH
M+OH2
Figure 3. Metal-activated H2O as the nucleophile.
R
O
OR'
Lewis AcidR
O
OR'
H2O
R
O
OH+ R'OH
LA
R
O
OR'
LA
OH2
R
O
OR'
LA
OH H
H+ trans
4
Lewis acid catalysis in stereoselective aldol additions
The following is a non-biological example of Lewis acid catalysis. Evans has
reported examples of Lewis acid catalysts used to obtain stereoselectivity in aldol
addition reactions. The systems usually employ a metal and multidentate ligand complex.
The metals used include Cu(II), Zn(II), Sn(II), and Sc(III).6, 7 The ligand usually contains
three nitrogens, in a pyridine or oxazoline. The complex binds the substrate (reaction
intermediate) in at least two locations, providing a stereospecific template for catalysis.
High enantiomeric excess is achieved for the catalyzed aldol reactions. Figure 4 below
contains two examples of such systems. The aldehyde and ether oxygen of the substrate
coordinate to the metal center of the complex in a specific manner, as this is directed in
part by sterics of the ligand and substrate in the transition state. This tool has become
useful in chiral synthesis.
BnOO
H+
OTMS
S BnOOH O
S99 % ee (S)
O N
Ph
N NO
PhCu
5 mol % cat
-78 °C
OHRO
RH
2+
2 SbF6-
Figure 4. Top: metal complex catalyst and substrate, Bottom: stereospecific catalyzed reaction.6
5
Metal activated hydrolysis of amino acid methyl esters
The first report of metal ion catalyzed ester hydrolysis was published in 1951.8
The study looked at the participation of several divalent metals and their effect on the
hydrolysis of various amino acid methyl esters. In the pH range of 7.5 to 8.5 it was found
that certain divalent metal ions increased the rate of hydrolysis. In the absence of the
metal, the hydrolysis was quite slow. The rate in such systems is second order and is
sensitive to pH. The exchange between the ligand and metal is rapid which makes
hydrolysis the slow step. The effectiveness of hydrolysis was also found to be dependent
upon a stable metal-ligand complex (Figure 5).8
H C C
NH2
OR'
O
M2+R
H C C
H2N
OR'
O
R
M2+
H C C
H2N
OR'
O
R
M2+
H C C
H2N
OR'
O
R
M2+
-OH
OH
H C C
H2N
OH
O
R
M2+
+R'OH
Figure 5. Metal-catalyzed hydrolysis of an amino acid ester.8
6
Metal ion catalysis in vivo
The metals Zn, Fe, and Cu are of importance to biological systems. It is estimated
that an adult human body contains 2-3 g Zn, 4-6 g Fe, and about 250 mg Cu.9 There are
numerous examples of naturally occurring metalloproteases. Approximately one out of
three enzymes known involves metal ions as tightly bound cofactors.9 Much progress has
been made on elucidating the mechanisms of peptide and nucleic acid hydrolysis. There
are on the order of 300 zinc based enzymes and of these approximately 20 have been
characterized by X-ray crystallography.10 Enzymes often contain metal active sites
designed specifically for certain metals. The class of enzymes called hydrolases has been
found to utilize transition metal centers such as Zn(II), Mn(II), and Fe(II). A sample of
biologically relevant systems is listed in Table 2.
Table 2. Selected hydrolytic enzymes and corresponding metals.11 Enzyme Function Metal Bovine lens leucine aminopeptidase N-Terminal amino acid hydrolysis Zn(II) Aminopeptidase from Aeromonas proteolytica Zn(II) Aminopeptidase from Streptomyces griseus Zn(II) Aminopeptidase P Mn(II) Methionyl aminopeptidases Fe(II) or Co(II) Carboxypetpidase G2 Folates to pteroates and L-glutamate Zn(II) Alkaline phosphatase Phosphate monoester hydrolysis Zn(II)/Mg(II) Phospholipase C Phosphatidylcholine hydrolysis Zn(II)/Mg(II) P1 Nuclease Phosphate diester hydrolysis Zn(II)/Mg(II) Purple acid phosphatases Phosphate ester hydrolysis Fe(III/II) Phosphotriesterase Organophosphate ester hydrolysis Zn(II) Arginase Hydrolysis of L-arginine Mn(II) Enolase Hydrolysis of 2-phospho-D-glycerate Mn(II) β-Lactamase β-Lactam degradation Zn(II) Urease Hydrolysis of urea Ni(II)
7
Carbonic Anhydrase
Carbonic anhydrase is the metalloenzyme responsible for catalyzing the following
reversible reaction:
CO2 +H2O HCO3- + H+
The first elucidation of the system was reported in 1940.10 The enzyme active site
involves three His residues and H2O coordinated to Zn(II). The crystal structure of the
active site is depicted in Figure 6.
Figure 6. Human carbonic anhydrase active site.12
Figure 7 illustrates the mechanism that transforms carbon dioxide into bicarbonate
ion. Polarization of H2O by Zn(II) encourages the metal-bound –OH nucleophile to
attack the carbon of CO2. The presence of the metal allows for nucleophilic –OH to exist
in conditions below neutral pH. Metal cations are advantageous over protons because the
concentration can be high at a physiological pH.9 An important feature of the crystal
8
structure is that the Zn2+ appears to coordinate to 5 sites. The metal is thought to be
responsible for orienting the CO2, polarizing it, and polarizing a nucleophilic H2O.
Zn2+
Im
Im
Im OH
CO
O
H2O
Zn2+
Im
Im
Im OH
+ H O CO
OIm = imidazole ring of His
CO2Zn2+
Im
Im
Im OH
H
-H+Zn2+
Im
Im
Im O
O
OH
Figure 7. Metal-catalyzed mechanism of carbonic anhydrase.13
Synthetic metalloenzymes
Chemists often investigate how nature performs chemical transformations and
apply that knowledge to synthetic models. The difficulty with such endeavors is usually
the lack in efficiency when compared to the biological system. Many of the recent
developments in this area involve complex inorganic catalysts, often containing multiple
metal ions.14 The role of synthetic RNA-cleaving metalloenzymes (metallonucleases)
has been studied. A proposed mechanism of hydrolysis is shown in Figure 8. The
hydrolysis yields a cyclic phosphate and the alcohol on the previously adjacent sugar. An
example of a synthetic metal-ligand complex used in an RNA hydrolysis rate experiment
9
is also shown. The work done by Morrow et al utilized multidentate nitrogen donor
ligands with metals such as Zn(II), Ni(II), Cu(II), Co(II), Co(III), and Pd(II).14
UOO
OO HPORO O
5'
Mn+
O H
γ mode RNA hydrolysis
N
N
N
RO Cu2+
synthetic metallonuclease
UOO
OO
5'
POO
+
ROH
Figure 8. RNA hydrolysis mechanism and synthetic metallonucleases.14
In 2003, Bazzicalupi et. al. reported a 1,10-phenanthroline-based cyclic ligand
designed for Zn(II) binding (Figure 9). Several dipeptides and a molecule with an
activated peptide were able to coordinate to the complex and hydrolysis of the amide was
observed. The proposed mechanism is outlined in Figure 9. Activation of H2O by Zn(II)
provides a nucleophile for the hydrolysis. The coordination complex geometry allows for
the nucleophile to be in proximity of the amide carbonyl group.
10
Figure 9. Synthetic metalloprotease designed to cleave dipeptides.15
Photochemical isomerization of alkenes
Molecular photochemistry is a branch of chemistry that is concerned with
reactions of molecules resulting from the absorption of photons.16 It is common for
unsaturated molecules to undergo geometrical isomerization upon absorption of light. In
Figure 10, the alkene is transformed from the trans isomer to the cis isomer.
H
R'
R
H
R'
H
R
H
hv
E Z
Figure 10. Photochemical isomerization of an alkene.
11
Upon absorption of a photon, an alkene π electron is excited and promoted into a
higher orbital, breaking the rigid double bond and allowing for twisting about the carbon-
carbon bond to occur (Figure 11). In the excited state, one electron is in an antibonding
orbital and one is in a bonding orbital, meaning no overall π bonding.17 In a simplified
sense, the molecule can be thought of as a diradical.18 A bond rotation of 180° may occur
if the molecule is transitioning to a more stable excited state.18 The rigid double bond
may take either the E or Z conformation, in which the two alkene substiutents are 0° or
180° with respect to each other. These two alkene conformations are lower energy and
more stable than the conformations 90° with respect to each other. The unfavorable
conformations are high in energy due to steric repulsion. The electron returns to the
ground state via a radiationless transition, an electronic transition between two states
(with the same spin) that does not involve the emission or absorption of a photon.
When the rate of conversion to the cis species equals the rate of conversion to the
trans species, the molecule is said to be in a photostationary state.16 It is possible to drive
the photochemical reaction to only one isomer or the other. This is dependent upon the
relative stability and the light absorbing properties of each isomer. For two isomers that
absorb light equally, isomerization usually occurs in favor of the conformation with the
lowest energy. A buildup of one isomer may occur if it does not absorb light as well as
the other isomer. It is common for UV light to provide the correct energy for
isomerization to occur.17
12
Figure 11. Alkene energy surface diagram.16
Cinnamate ester deacylation photochemistry In the late 1980’s Porter reported a system for the photochemical control of
biologically-relevant molecules. This consisted of tethering the molecule of interest to
the substrate, forming a caged compound. The cinnamate cage rendered the biomolecule
inactive. It inhibited serine proteases by targeting the active site.19 Light could be used
to induce the return of biological activity. A series of cinnamate esters were prepared for
deacylation upon irradiation with near ultraviolet light (366 nm was actually used).
Different enzymes (Enz = chymotrypsin, thrombin, Factor Xa) and alkyl groups were
linked to the acyl substituent.20
13
OH
Et2N
OOEnz OH
Et2N
EnzOOC366 nm hv
Et2N
O
O
Enz-OH +
X = leaving group
OH
Et2N
OX Enz-OH
(active site)
Figure 12. Cinnamate ester deacylation photochemistry.20
Figure 12 describes the photochemical activity of the system. The para-diethyl
amino group was introduced to red shift the maximum absorbance from 280 nm to 360
nm. Upon irradiation the E conformation isomerizes to the Z conformation, providing the
necessary proximity of the nucleophilic OH oxygen to attack the ester carbonyl.
Lactonization of the cinnamate was observed in the dark and an alcohol was released.20
It was found that deacylation occurs >109 times faster in the cis isomer than the trans
isomer, and this differential is critical to the operation of an effective photochemical
switch. More recently, the group reported photo cleavage of an amide linkage analogous
to the ester linkage previously described.21 This system employed o-aminocinnamates
rather than the previously discussed o-hydroxycinnamates. The photolysis occurred only
in slightly acidic conditions (pH 4-5 buffer).
14
Photoactivated artificial metalloenzymes This thesis details the progress made towards developing and investigating a
number of photoactivated artificial metalloenzymes. The synthesis of a typical system
involves linking or caging a molecule by attaching it to a ligand system. The modified
ligand must be complexed with a suitable metal in a solvent system containing water.
The reaction of the complex with light and the subsequent caged molecule release can
then be studied. This thesis describes the development, photochemistry, and possible
applications of several systems.
15
REFERENCES
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2. Darbre, T., Dubs, C., Rusanov, E., Stoeckli-Evans, H., “Syntheses of Zinc Complexes with Multidentate Nitrogen Ligands: New Catalysts for Aldol Reactions,” Eur. J. Inorg. Chem. 2002, 12, 3284-3291.
3. Zong, R., Thummel, R.P., “2,9-Di-(2'-pyridyl)-1,10-phenanthroline: A
Tetradentate Ligand for Ru(II),” J. Am. Chem. Soc. 2004, 126, 10800-10801.
4. Skoog, D.A., West, D.M., Holler, F.J., Crouch, S.R., Analytical Chemistry: An Introduction. 6th ed. Saunders College Publishing: Philadelphia: 1994.
5. Breslow, R., Belvedere, S., Gershell, L., Leung, D., “The chelate effect in binding,
catalysis, and chemotherapy,” Pure Appl. Chem. 2000, 72(3), 333-342.
6. Evans, D. A.; Murry, J. A.; Kozlowski, M. C., “C2-Symmetric Copper(II) Complexes as Chiral Lewis Acids. Catalytic Enantioselective Aldol Additions of Silylketene Acetals to (Benzyloxy)acetaldehyde,” J. Am. Chem. Soc. 1996, 118(24); 5814-5815.
7. Evans, D.A., Masse, C.E., Wu, J., “C2-Symmetric Sc(III)-Complexes as Chiral
Lewis Acids. Catalytic Enantioselective Aldol Additions to Glyoxylate Esters,” Org. Lett. 2002, 4(20), 3375-3378.
8. Kroll, H., “The Participation of Heavy Metal Ions in the Hydrolysis of Amino
Acid Esters,” J. Am. Chem. Soc. 1951, 74, 2036-2039.
9. Voet, D., Voet, J.G., Pratt, C.W., Fundamentals of Biochemistry. Wiley: New York, 1999.
10. Cotton, F.A., Wilkinson, G., Murillo, C.A., Bochmann, M., Advanced Inorganic
Chemistry. 6th ed., Wiley: New York, 1999.
11. Holz, R. C., “The aminopeptidase from Aeromonas proteolytica: structure and mechanism of co-catalytic centers involved in peptide hydrolysis,” Coord. Chem. Rev. 2002, 232, 5-26.
12. Sheridan, R.P., Allen, L. C., “The Active Site Electrostatic Potential of Human
Carbonic Anhydrase,” J. Am. Chem. Soc. 1979, 103, 1544-1550.
13. Fersht, A., Enzyme Structure and Mechanism. 2nd ed., Freeman: New York, 1985.
16
14. Morrow, J.R., Iranzo, O., “Synthetic metallonucleases for RNA cleavage,” Curr.
Opin. Chem. Biol. 2004, 8, 192-200.
15. Bazzicalupi, C.; Bencini, A.; Berni, E.; Bianchi, A.; Fornasari, P.; Giorgi, C.; Valtancoli, B., “Zn(II) Complex with a Phenanthroline-Containing Macrocycle as Receptor for Amino Acids and Dipeptides - Hydrolysis of an Activated Peptide Bond,” Eur. J. Inorg. Chem. 2003, 1974-1983.
16. Turro, N.J., Modern Molecular Photochemistry. University Science Books: 1991.
17. Clayden, J., Warren, S., Greeves, N., Wothers, P., Organic Chemistry. Oxford
University Press: 1999.
18. Suppan, P., Chemistry and Light. Royal Society of Chemistry: Cambridge, 1994.
19. Thuring. J. W.; Porter, N. A., “Comparative Study of the Active Site Caging of Serine Proteases: Thrombin and Factor Xa,” Biochemistry 2002, 41, 2002-2013.
20. Porter, N. A.; Bruhnke, J.D., “Acyl Thrombin Photochemistry: Kinetics for
Deacylation of Enzyme Cinnamate Geometric Isomers,” J. Am. Chem. Soc. 1989, 111, 7616-7618.
21. Li, H., Yang, J., Porter, N.A., “Preparation and photochemistry of o-
aminocinnamates,” J. Photochem. and Photobiol. A: Chemistry. 2004, 169, 289-297.
17
RESULTS AND DISCUSSION
Background
The proposed photoactivated artificial metalloenzyme needs to possess the
following properties: adequate light absorbance, water soluble complexation with a metal,
and multidentate metal binding. Figure 13 illustrates the following hypothesis. A
multidentate ligand serves as the base structure and chromophore. Ultraviolet or visible
light absorption would be necessary, while the latter is preferred keeping in mind possible
in vivo applications. A trans alkene is linked to a caged species via an ester or amide
linkage. This is tethered to the ligand, keeping the alkene in conjugation with the
chromophore. The ligand is complexed with a suitable cationic metal in aqueous solution.
H2O is polarized at the metal center, generating -OH. The ligand would need to
coordinate to the majority of the metal’s binding sites without saturating them, leaving at
least one free site for H2O or -OH to reside. It is desirable that one molecule of ligand
coordinates to one metal ion.
The trans isomer keeps the ester or amide carbonyl away from the nucleophile.
Irradiation of the complex induces photoisomerization of the alkene from the trans
isomer to the cis isomer. Isomerization is driven to completion (or near completion) by
the stability of carbonyl coordination to the metal. Once the carbonyl is “locked” into
place near the metal center, it is in close proximity to nucleophilic –OH (comes from
metal-activated H2O), which may hydrolyze the ester. This frees the caged species
(alcohol or amine) and generates a carboxylate or carboxylic acid coordination adduct.
18
M+
ORO
hν
trans to cisisomerization
H2O
HO
M+H2O
ligand ligand
H2OO
+ ROH
O
M+H2O
ligand
O
ROHO
esterhydrolysis
Figure 13. General photoactivated metalloenzyme scheme.
Mono-substituted 1,10-phenanthroline ligands
1,10-Phenanthroline was chosen as the prototype ligand substrate for its binding
properties as well as light absorption characteristics. The three conjugated aromatic ring
systems are suitable for light absorption. The ability for modification on the carbon
adjacent to each of the two nitrogen atoms is important. A prototype ligand was
synthesized in which a caged alcohol side-chain was linked as an ester (Figure 14).
Methyllithium was inserted into commercially available 1,10-phenanthroline.1 The mono
methyl product (1) was converted to the aldehyde (2) by oxidation with selenium
dioxide,2 followed by a Wittig olefination with a commercially available stabilized ylide.
NN
1) CH3Li, benzene
2) bleachN
NN
N
CHO
SeO2
1,4-dioxane
Ph3P=CHCO2R
benzene, refluxN
N
OOR
R=CH3, Bn
(1) (2)
(3, 4)
68 % 75 % 96-99 %
Figure 14. Synthesis of the 1,10-phenanthroline ligands (3) and (4).
19
Photochemistry of ligand (3)-Zn(II) complex
Following the synthesis of methyl ester ligand (3), a preliminary photolysis was
designed to evaluate the proposed hypothesis. Zn(II) sulfate was then chosen as the
prototype metal salt due to compatibility with NMR analysis (diamagnetic). The
complex of ligand (3) and ZnSO4 (51 mM in 10:1 DMSO-d6 : D2O) was irradiated at 366
nm (450 W lamp) for 11.5 hours at which point 1HNMR analysis showed the conversion
of the majority of the trans isomer to the cis isomer (Figure 15, monitored alkene
doublets). The presence of a new singlet at 2.09 ppm was observed, indicating that the
methyl ester had been hydrolyzed.
Figure 15. 1HNMR trace of preliminary photolysis and generation of MeOH (CH3 indicated).
ppm (t1)2.03.04.05.06.07.08.09.0
ligand, zinc sulfate, light 11.5 hr
20
This finding presented the task of quantifying the efficiency of the observed
alcohol hydrolysis. In a preparative scale reaction, an isolated yield of methanol would
be difficult to determine. A ligand with a less volatile caged alcohol would need to be
developed. A commercially available benzyl ester ylide (Ph3P=CHCO2CH2Ph) was
substituted for the methyl analog in the Wittig portion of the ligand synthesis.
Photochemistry of ligand (4)-Zn(II) complex
The evaluation of ligand (4) was carried out with 1HNMR using 4 tubes. This
covered the following variables: presence of ligand, metal, light, and dark. If the
hypothesized activity had occurred, then ester hydrolysis would only be observed in the
tube with ligand, metal, and exposure to light. Two tubes contained 25 mM ligand and
24 mM ZnSO4·7H2O, while the other two tubes were charged with ligand but not metal.
The solids in each tube were dissolved in 10:1 DMSO-d6 : D2O. Two tubes (ligand +
metal and ligand only) were irradiated at 366 nm (450 W lamp) for 11.5 hours. The tubes
were monitored by 1HNMR at t=0, 4.5 h, and 11.5 h, at which point the alkene was fully
isomerized. A singlet consistent with benzyl alcohol CH2 (4.49 ppm) appeared only in
the spectrum associated with ligand, metal, and light, confirming that photochemically-
induced activity was occurring (Figure 16). No hydrolytic activity took place without
irradiation.
21
no light; ligand
no light; ligand; zinc
11hr light; ligand ppm (t1)2.0 3.0 4.0 5. 06.0 7.0 8.0 9.0 11hr light; ligand; zinc F i g u r e 1 6 . B e n z y l e s t e r p h o t o l y s i s 1H N M R t r a c e s .
Q u a n t i f y i n g t h e h y d r o l y s i s e f f i c i e n c y
I n o r d e r t o m a x i m i z e t h e d e s i r e d h y d r o ly s i s , a n a q u e o u s e n v i r o n m e n t w o u l d b e
r e q u i r e d . A p r e p a r a t i v e s c a l e i s o l a t e d y i e l d o f b e n z y l a l cohol would also prove to be
d i f f i c u l t , a s b e n z y l a l c o h o l a n d w a t e r f o r m a n a z e o t r o p e ( 9 % B n O H , 9 1 % H 2O , B P = 1 0 0
° C ) . 3 T h e 0 r e a c t i o n w a s c a r r i e d o u t i n d i l u t e 2:1 methanol:water, with a 104 mM
c o n c e n t r a t i o n o f b o t h l i g a n d a n d Z n ( I I ) . T h e r e a c t i o n m i x t u r e w a s ir r a d i a t e d a t 3 6 6 n m
( 4 5 0 W 0 l a m p ) u n t i l n o s t a r t i n g m a t e r i a l w a s d e t e c t e d b y G C . T h e m e t h a n o l w a s r e m o v e d
u n d e r v a c u u m a n d t h e r e m a i n i n g w a t e r w a s e x t r a c te d w i t h e t h y l a c e t a t e . A l l b u t a t r a c e
22
of benzyl alcohol was lost in an azeotrope with water on the rotary evaporator. Yield
determination inferred by instrumental analysis would be necessary.
An experiment was devised to evaluate the efficiency of ester hydrolysis (Figure
17). Gas chromatographic analysis was the method of choice for quantification of benzyl
alcohol. A five-point calibration curve using 1-octanol as the internal standard was
established. A dilute 1.4 mM solution of ligand (4) and ZnSO4 in 2:1 MeOH:H2O (0.8
equivalents 1-octanol internal standard) was irradiated at 366 nm (450 W lamp) for 16
hours. The solution was extracted with EtOAc which was analyzed for BnOH by GC,
indicating 20 % hydrolysis of the benzyl ester.
NN
OOBn
2:1 MeOH:H2O
ZnSO4350 nm hvMed. pressure Hg vapor lamp
OH
20 %
Figure 17. Evaluation of the extent of ester hydrolysis by GC.
Both ligands (3) and (4) formed Zn(II) complexes that were insoluble in H2O (at
1HNMR sample concentrations, ~10 mM). Cu(II) provided a water-soluble complex with
both ligands. The UV/Visible spectrum of the Cu(II) complex (5.9 x 10-5 M in H2O)
shows a λmax at 359 nm (Figure 18).
23
NN
OBnO
Cu2+
Ln
359
-0.05
0.05
0.15
0.25
0.35
0.45
0.55
250 270 290 310 330 350 370 390 410 430 450
wavelength (nm)
Abs
Ln
Figure 18. UV/visible spectrum of ligand (4) – Cu(II) complex.
Fast exchange at the metal center
Zn(II) commonly takes on four coordinate covalent bond donors to form a
tetrahedral ligand-metal complex. Ligands (3) and (4) both have two N binding sites,
leaving two sites open. Broad aromatic signals were observed in the 1HNMR spectrum
of the complexes of ligand (3) or (4) and ZnCl2 in DMSO-d6, suggesting that fast
exchange of H2O was occurring at the metal center. The ligand (3) complex (25 mM)
was spiked with 10 equivalents of LiCl. The excess Cl- served to suppress the fast
exchange of H2O and sharpen the 1HNMR spectrum aromatic region (Figure 19).
24
Zn ︵II ︶ chloride complex
Zn ︵II ︶ chloride complex + 10 equiv LiCl
ppm (t1)7.007.508.008.509.009.50
Figure 19. 1HNMR traces showing the effect of Cl- on the complex.
The mono-functionalized 1,10-phenanthroline ligand system is bidentate,
allowing for the possibility of two ligands binding to one metal ion. This scenario, ML2,
could suppress hydrolytic activity by saturating the metal coordination sites and thus
reducing the number of bound H2O molecules on the metal surface. For reasons of poor
water solubility, fast exchange at the metal center, and the possible ML2 effect, an
improved ligand system was sought after.
Pyridine ligands
Two ligands were designed with a pyridine chromophore. Pyridine has only one
intrinsic binding site in comparison with the two found in phenanthroline, thus a second
substituent was attached to the substrate in order to provide extra metal coordination sites.
This new addition of heteroatoms provided an opportunity to increase water solubility.
25
The difficulty often observed with trying to asymmetrically functionalize a symmetrical
molecule was overcome with chemistry designed to mono-tosylate 2,6-
pyridinedimethanol.4 The monotosylate was displaced with bis(2-methoxyethyl)amine.
The alcohol was converted to the aldehyde via a Swern oxidation,5 followed by a Horner-
Emmons olefination. Figure 20 illustrates the synthetic scheme for the first pyridine
ligand (8).
NHO OH N
OTsHOTsCl, KI, Ag2O
NH
+
K2CO3acetone
NN
NN
OHCNN
OBn
O OH
Swern Ox.
(EtO)2P CO2BnO
NaH
OO
O
O
O
O
O
O
(5)
(6)(7)(8)
75 %
84 %73 %54 %
Figure 20. Synthesis of ligand (8).
Photochemistry of ligand (8)-Zn(II) complex
The ZnSO4 complex of the methoxy ligand (8) was soluble in 3:1 DMSO-d6:D2O.
This was a 2.5-fold improvement from phenanthroline ligands (3) and (4), but did not
achieve the ultimate goal of water-solubility. A complex (ZnSO4 and ligand, 20 mM in
3:1 DMSO-d6:D2O, 2,4,6-trimethyl benzoic acid internal standard) was irradiated at 350
nm (Rayonet lamp) for 6 hours. The solution was monitored by 1HNMR for one week in
the dark. These preliminary results are given in Table 3. Due to incomplete water
26
solubility, this ligand was not pursued any further and efforts were then shifted to the
target molecule (11).
Table 3. Photolysis of Zn(II)-ligand (8) complex Time % yield BnOH
0 hr hv 02 hr hv 4.66 hr hv 101 day dark 9.7
1 week dark 18
CO2H
internal standard
The synthesis of (11) was carried out by the same route as with (8), with the
substitution of 2-picolylamine for bis(2-methoxyethyl)amine (Figure 21). It was
hypothesized that ligand (11) would be more water soluble than ligand (8) and that the N-
metal binding would be stronger than O-metal binding. Figure 22 illustrates the proposed
“cup-like” binding of the ligand to a cationic metal.
NHO OH N
OTsHOTsCl, KI, Ag2O
NNH N+
K2CO3acetone
NN
N
N
NN
OHC
N
N
NN
N
N
OBn
O OH
Swern Ox.
(EtO)2P CO2BnO
NaH
(5)
(9)(10)(11)
75 %
85 %65 %51 %
Figure 21. Synthesis of ligand (11).
27
NN
N
N
OBn
O
M2+N
N N
CO2Bn
M2+ N
(11)
Figure 22. Proposed ligand-metal complex equilibrium.
Photochemistry of ligand (11) and an array of metals
Ligand (11) formed water-soluble complexes with the following metals: Ni(II),
Fe(III), Zn(II), Co(II), and Cu(II). The ligand was dissolved in 1 part MeOH and the
metal salt (sulfate anion) was taken up in 9 parts H2O. The ligand was added slowly to
the metal, yielding the clear colored or colorless complex in solution. The complex is
completely water-soluble, but by dissolving the ligand in minimal MeOH, it is allowed to
mix with the metal in solution, providing a faster complexation. It is possible to form the
complex in the absence of a co-solvent, but this requires more time and vigorous
agitation.
Ligand (11) was complexed with an array of 5 metal salts (9:1 H2O : MeOH, 11
mM in H2O, 0.3 equivalents 1-octanol internal standard). The hydrolysis efficiency of
the 5 complexes was analyzed after irradiating at 350 nm (Rayonet lamp) for 6 hours.
The samples were kept in the dark for one week at which point the aqueous solution was
extracted with 1 mL Et2O. The extract was analyzed by GC and with the aid of a five
point calibration curve, the yield of hydrolysis value was determined. Figure 23 shows
the complexes (from left to right: NiSO4, ZnSO4, Fe2(SO4)3, CuSO4, CoSO4). Table 4
reports the results from the photolysis experiment. Cu(II) displayed a significantly higher
percent hydrolysis than the rest. This metal was chosen to be used in subsequent analyses.
28
Figure 23. Water-soluble metal complexes with ligand (11).
Table 4. Ester hydrolysis with an array of metals. Metal % hydrolysis
2578
17
Ni2+
Fe3+
Zn2+
Co2+
Cu2+
rel. % hydrolysis
1345
11
The major fault of this system lies in its light absorbance. The UV-Vis spectrum
of the Cu(II)-ligand (11) complex is shown in Figure 24. Since two of the pyridines are
not in conjugation with each other or the alkene, the lone pyridine conjugated to the
alkene serves as the chromophore. The complex absorbs well only below 300 nm. This
is light of higher energy (lower λ) than is desired, as their photoreactions tend to be
lengthy and less selective than those of lower energy (higher λ).
29
Figure 24. UV-visible absorption spectrum of Cu(II)-ligand(11)complex in MeOH
(4.2 x 10-5 M in H2O).
Effect of buffered aqueous media
The aqueous Cu(II)-ligand (11) complex was evaluated with two different buffers
(Table 5). Each complex was 5 mM in ligand and CuSO4, in 9:1 aqueous buffer : MeOH
(0.5 equivalents 1-octanol internal standard). The blue complexes were irradiated at 350
nm (Rayonet lamp) for 6 hours and kept in the dark for two days before GC analysis of
the Et2O extract. The pH 5.0 buffer (10 mM potassium hydrogen phthalate/NaOH)
provided the poorest performance. The pH 7.0 (10 mM ammonium acetate) and
unbuffered samples did not produce results of significant difference.
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
230 250 270 290 310 330 350 370 390
wavelength (nm)
Abs
N
N N
CO2Bn
Cu2+ N
λmax=291 nm
30
Table 5. Effect of buffer on hydrolysis efficiency Buffer pH Rel. % hydrolysis
5.0 0.1 7.0 1
Unbuffered 1
The use of Cu(II) limited the ability to monitor alkene isomerization
(completeness of irradiation) by 1HNMR. An experiment was devised to determine the
optimal duration of light exposure. The complexes were 7.7 mM in ligand and CuSO4, in
8:2 H2O : MeOH (0.8 equivalents of 1-octanol internal standard). The samples were
irradiated at 350 nm (Rayonet lamp) for 0, 2, and 6 hours at which point they were placed
in the dark. Hydrolysis efficiency was monitored by analyzing the Et2O extract of each
solution by GC (internal standard: 1-octanol). Isomerization was likely slow due to the
light absorbance in the ultraviolet region (291 nm). Approximately 80 % hydrolysis
efficiency was observed after 25 days in the dark (Figure 25). A dark control experiment
was built into the experiment (0 hr light) and indicated trace hydrolysis without
irradiation. This suggests that the hydrolysis is light activated.
31
Figure 25. Long term ester hydrolysis in the dark as a function of light exposure.
A preparative scale reaction was devised to obtain an isolated yield of benzyl
alcohol. The complex (0.171 g scale) was 3.7 mM in ligand and CuSO4 (9:1 NH4OAc
buffer : MeOH). The complex was irradiated at 350 nm (Rayonet lamp) for 6.25 hours
then placed in the dark for 20 days. The solution was extracted with Et2O, which was
evaporated to dryness, yielding a benzyl alcohol recovery representing 12 % ester
hydrolysis.
Symmetrical di-substituted 1,10-phenanthroline ligand
A symmetrical analog of the 1,10-phenanthroline based ligand was developed.
The relative ease of synthesis was made possible by the commercial availability of the
starting material, neocuproine. A simple SeO2 oxidation8 of both methyl groups gave the
0
10
20
30
40
50
60
70
80
90
0 5 10 15 20 25
dark hydrolysis time (days)
GC
% y
ield
BnO
H
2 hr hv
6 hr hv
0 hr hv
N
N N
CO2Bn
Cu2+ N
32
very insoluble dialdehyde (12). A Horner-Emmons olefination gave the desired di-alkene
(13) (Figure 26). The UV-Visible spectrum of the ligand(13)-Cu(II) complex is shown in
Appendix C. The complex has similar absorbance as was seen with complexes of ligands
(3) and (4).
NN
SeO2
1,4-dioxaneN
N
CHO
OHC NN
OEtO
OEt
O
P(O)(OEt)2CH2CO2Et
NaH, DMF
(12) (13)
Figure 26. Synthesis of the symmetrical phen ligand.
A simple proof-of-principle experiment (Figure 27) was designed to test whether
this ligand-metal complex would photolyze as predicted. Ligand (13) was complexed
with Zn(II) in 9:1 DMSO-d6:D2O (1 mL, 10.6 mM). The solution was irradiated at 350
nm (Rayonet lamp) and followed by 1HNMR until the trans alkene signals disappeared
(70 minutes) and cis alkene signals grew in (Table 6). The solution was kept in the dark
and monitored by 1HNMR over the course of one week. The spectrum of the cis complex
at one week is reported in Figure 28, showing the appearance of EtOH. It is important to
note that the conversion to cis went to completion, a result not seen with ligands (3) and
(4), likely due to the stability from both of the carbonyl groups coordinated to the metal.
This satisfies 4 coordination sites on Zn(II) and reduces fast exchange of other ligands.
The dark control complex did not show any signs of hydrolysis at one week.
33
ZnSO4
D2O, DMSO-d6
350 nm hvN
N
CO2Et
EtO2C
EtOH
(13)
N
N
CO2Et
EtO2C Zn2+
N
N2+ZnO
OOEt
EtO
dark
N
N2+ZnO
OOH
HO
+
Figure 27. Proof-of-principle experiment scheme.
Table 6. Photoisomerization of the di-alkene. irradiation time % cis % trans
0 0 100 15 min 35 65 35 min 75 25 70 min 100 0
34
ppm (t1)1.001.502.002.503.003.50
Figure 28. 1HNMR trace showing EtOH CH2 and CH3 signals.
Figure 29 depicts the proposed Zn(II) cis complex, with approximate tetrahedral
geometry. The isomerization of the alkenes from trans to cis would satisfy the four
coordination sites on the Zn. The geometry would most likely be a distorted tetrahedron,
making the whole complex chiral. There would be a left or right handed twist in the axis
perpendicular to the plane of the phenanthroline.
N
NZn2+
OOEtO
EtO
Figure 29. Proposed structure of the di-cis Zn(II) complex.
35
Pyridine-phenanthroline ligand
A third general type of ligand was prepared, merging the properties of the 1,10-
phenanthroline and pyridine ligands. In the pyr-phen ligand series, the base unit consists
of 1,10-phenanthroline conjugated to pyridine (Figure 30). This ligand was synthesized
with the prediction that the light absorbance would be shifted to a higher λ and that an
extra metal-binding N would reduce or limit M(L)2 and provide stronger complexation.
Commerically available (and inexpensive) 6-amino-2-picoline was converted by
diazotization to 2-bromo-6-methyl pyridine (14) on a 100 g scale in 63 % yield.6 The 2-
bromo-6-methyl pyridine was treated with n-BuLi, forming the lithiate which was added
into the 2 position of 1,10-phenanthroline. An oxidation (rearomatization) with
household bleach gave the compound (15) in 54 % yield. This methylated compound
was oxidized to aldehyde (16) in 77 % yield by refluxing in DMSO with I2,
trifluoroacetic acid and t-BuI.7
NN
NNN
N Li
THF I2, TFA, t-BuIN
NN
CHO
DMSO
(EtO)2P CO2RO
NaH
NNN
O OR
n-BuLi
N Br
1) HBr, Br2, NaNO22) NaOH
N NH2
(14)
(15) (16)
(17) - OBnor OEt
(18) - OBn, 61 %(19) - OEt, 57 %
54 %
63 %
77 %
Figure 30. Synthesis of ligands (18) and (19).
36
The method for the pyridine methyl oxidation was chosen after the previously
used SeO2 method proved to be inefficient. The two pathways are illustrated in Figure 31.
Even though the optimized reaction takes multiple days to go to completion, it yields
greater than three times the product. It also eliminates the use of selenium dioxide, a
toxic compound that is difficult to remove from the aldehyde.
NNN
I2, TFA, t-BuI, DMSO
NNN
CHO
3 d, 77 % y
SeO2, dioxane
6 h, 24 % y
(15) (16)
Figure 31. Comparison of the two routes to the aldehyde
The aldehyde was reacted separately with benzyl diethyl phosphonoacetate (17)
and triethyl phosphonoacetate in a Horner-Emmons olefination, yielding ligands (18) and
(19) in 61 % and 57 % yield, respectively. Compound (18) was synthesized for
preliminary studies, while compound (19) was synthesized on a larger scale for further
modification of the OEt group.
37
Figure 32. Core compound strategy.
Aldehyde (16) was converted to the olefinated ethyl ester (19) via the Horner-
Emmons reaction with the commercially available triethyl phosphonoacetate. A mild
hydrolysis with LiOH in wet THF yielded the lithium carboxylate (20). Figure 32
illustrates the core compound strategy that was originally proposed. A core ligand (the
carboxylate) was prepared so that analog esters could be easily synthesized in one
synthetic step. This would make the system an option for the protection of various
alcohols, removable by photolysis.
NNN
NNN
coupling NNN
O OEtO O O OR
metal complex
hydrolysis
metal
hv
LiOH
THF/H2O(19)
Li+(20)
38
Evaluation of an array of esters
Five ester analogs were prepared as shown in Figure 33, with the corresponding
alcohol boiling points in mind. The alcohol boiling points needed to be high enough to
effectively obtain an isolated yield. The boiling points of the analogs were above that of
benzyl alcohol (>205 °C). The benzyl ester was used for optimization of the
photochemistry and hydrolysis.
NNN
O OR
lig
lig
lig
OMe
lig
O
O
lig
R =
(18)
(21)
(22)
(24)
(26)
Figure 33. Array of pyr-phen ligand esters.
Three of the esters were prepared by O-alkylation of the ligand carboxylate with
the corresponding bromide (Figure 34). The lithium carboxylate (20) was heated with the
bromide and one equivalent of CsF in dry DMF for 18-24 hours.
39
NNN
O OLi
60 °C
RBr, CsF, DMF NNN
O OR(21) phenethyl 24 h, 82 %(22) 4-methoxy benzyl 18 h, 80 % (24) ethyl valerate 20 h, 84 %
R = time yield(20)
Figure 34. Preparation of analogs by bromide alkylation.
Two of the ester analogs were prepared via Horner-Emmons olefination (Figure
35). Benzyl diethylphosphonoacetate was prepared by the Arbuzov Reaction. The L-(-)
menthol phosphonate ester was prepared by DCC coupling of commercially available
diethyl phosphonoacetic acid and L-(-) menthol. The Horner-Emmons reagent anion was
then reacted with aldehyde (16) in anhydrous DMF, as the aldehyde was found to have
lower solubility in other organic solvents.
NNN
O
NNN
O OR
PO
(EtO)2CO2R
NaH, DMF
R = benzyl (61 % y), menthyl (44 % y)(18) (26)
(16)
Figure 35. Preparation of analogs by Horner-Emmons olefination.
40
(EtO)2P CO2BnO
BrOBn
O
P(OEt)3
heat Figure 36. Preparation of benzyl diethylphosphonoacetate (17).
PO
OO
PO
OO
O
OH
O
O
L-(-) mentholDCC, DMAP
CH2Cl2
Figure 37. Preparation of the menthyl Horner-Emmons reagent (25).
The benzyl ester (18) was synthesized on a larger scale than the other analogs for
multiple optimization experiments. The optimization work focused on two metals: Zn(II)
and Cu(II), with the same SO42- counterion. The Zn(II) complex was studied at dilute 1.2
mM conditions to maximize H2O content in the solvent system (9:1 H2O:MeOH). The
methanol was necessary to dissolve the ligand in order for it to be slowly introduced to
the stirring aqueous metal solution. A slight excess of metal (1.15 equivalents) ensured
that all the ligand was complexed. The Cu(II) complex was soluble at a higher
concentration, but the lower 1.2 mM concentration was used for both metals. While both
complexes were clear solutions, the Cu(II) complex was light green and the Zn(II)
complex was pale yellow.
UV-Visible absorption spectra of the complexes indicated what wavelength of
light to use for irradiation (Figures 38-40). The ligand absorbs out to around 350 nm,
while both the Zn(II) and Cu(II) complexes absorb out to around 370 nm. The spectra
are presented below. All spectra showed concentration dependence proportional to
41
absorbance at 350 nm and 366 nm. Tables 7a-c detail the absorbance and molar
absorptivity data from the spectroscopic measurements.
UV-visible spectra
-0.1
0.1
0.3
0.5
0.7
0.9
1.1
1.3
1.5
250 270 290 310 330 350 370 390 410
wavelength (nm)
abso
rban
ce B, 4.5 x 10-5 MC 2.25 x 10-5 MD, 1.12 x 10-5 M
Figure 38. UV-Visible spectrum of benzyl ester ligand (18) in MeOH.
-0.1
0.1
0.3
0.5
0.7
0.9
250 270 290 310 330 350 370 390 410
wavelength (nm)
abso
rban
ce B, 4.5 x 10-5 MC 2.25 x 10-5 MD, 1.12 x 10-5 M
Figure 39. UV-Visible spectrum of benzyl ester-Zn(II) complex in H2O.
42
-0.1
0.1
0.3
0.5
0.7
0.9
1.1
1.3
1.5
250 270 290 310 330 350 370 390 410
wavelength (nm)
abso
rban
ce B, 4.5 x 10-5 MC 2.25 x 10-5 MD, 1.12 x 10-5 M
Figure 40. UV-Visible spectrum of benzyl ester-Cu(II) complex in H2O.
Tables 7a-c. UV-Vis data for benzyl ester ligand (18) and complexes.
a) ligand Concentration (M) Abs350 nm Є (L mol-1 cm-1)
350 nm Abs366 nm Є (L mol-1 cm-1)
366 nm 4.50 x 10-5 0.180 4000 0 0 2.25 x 10-5 0.0788 3500 0 0 1.12 x 10-5 0.0471 4200 0.0028 250
b) Zn(II) complex Concentration (M) Abs350 nm Є (L mol-1 cm-1)
350 nm Abs366 nm Є (L mol-1 cm-1)
366 nm 4.50 x 10-5 0.384 8600 0.400 8900 2.25 x 10-5 0.205 9100 0.219 9700 1.12 x 10-5 0.0806 7200 0.083 7400
c) Cu(II) complex Concentration (M) Abs350 nm Є (L mol-1 cm-1)
350 nm Abs366 nm Є (L mol-1 cm-1)
366 nm 4.50 x 10-5 0.519 12000 0.512 11000 2.25 x 10-5 0.234 10000 0.231 10000 1.12 x 10-5 0.102 9100 0.102 9100
43
Long wavelength absorption band of Cu(II) complex
A more concentrated Cu(II) complex indicated a broad absorbance band at long
wavelength (731 nm, Figure 41). The absorbance was concentration-dependent as well.
This finding gave rise to the possibility of a long wavelength, low energy photolysis.
Several experiments were devised to evaluate this property. A 1.2 mM aqueous Cu(II)
complex was irradiated for 10 h with >600 nm light. The solution was stirred in the dark
for 4 days at which point an aliquot was extracted with a dilute 1-octanol solution in ether.
The extracts were analyzed by gas chromatography, which indicated no benzyl alcohol
formation above the dark control baseline. Another experiment was carried out at 5.8
mM in DMSO (minimal water to dissolve the metal), in which the complex was
irradiated for 10 h with >600 nm light and stirred overnight in the dark. An aqueous
workup and extraction with CH2Cl2 gave only the starting material trans ligand,
indicating no photoisomerization at the long wavelength irradiation.
0
0.1
0.2
0.3
0.4
0.5
0.6
400 450 500 550 600 650 700 750 800
wavelength (nm)
abso
rban
ce A, 5.63 mMB, 4.6 mMC, 2.3 mM
Figure 41. 731 nm absorption band of benzyl ester copper complex in H2O.
44
Photoisomerization of ligand (18)-Zn(II) complex
The Zn(II) system allowed for structural monitoring by 1HNMR. The
photoisomerization was studied at 9.6 mM (4.0 mg ligand) in 9:1 DMSO-d6:D2O. The
higher concentration of complex allowed for performing a reasonable number of scans by
1HNMR. Intense light 350 nm (Rayonet lamp) was used for the experiment. Figure 42a
shows the course of photoisomerization via the monitoring of the broad benzyl CH2 peak
at 5.30 ppm. A broad quartet, centered at 5.16 ppm began to slowly appear just upfield
of the diminishing peak. By around 30 minutes, the photoisomerization was complete.
The peak broadness observed is attributed to fast exchange at the metal center and under
these conditions, the ML2 complex is likely dominant.
The coordination of the cis isomer to the metal allows for the complete
conversion from trans to cis. This is in contrast to the photostationary state of 1:1
cis:trans that is achieved when the ligand is irradiated without metal under the same
conditions (Fig 42b).
t=0
t=5 min
t=8 min
t=13 min
t=20 min
ppm (t1)5.0505.1005.1505.2005.2505.3005.3505.4005.450
t=40 min
Figure 42a. 1HNMR trace of benzyl CH2 during photoisomerization.
trans
cis
45
Figure 42b. 1HNMR spectra: photostationary state determination (1:1 cis:trans).
Chirality of the Zn(II) complex
The 1HNMR benzyl CH2 splitting pattern indicated that both the cis and trans
complexes are chiral, as the two hydrogens in each case are diastereotopic. They are split
by each other as they are in different chemical environments, producing the AB quartet.
Figures 42 and 43 indicate that both the trans and cis complexes are chiral about the
metal center. The diastereotopic hydrogens were resolved by 1HNMR in the dilute
solvent system (9:1 D2O:CD3OD). 128 scans were necessary as the sample was
approximately 10 times more dilute than is required for a routine 16 scan experiment. A
problem presented itself as the residual H2O peak was very large and close to the benzyl
CH2. Water suppression was employed to attenuate the interfering peak. (P1=8.30 µsec,
PL1=0 dB, PL9=55.60 dB). Figure 43 shows the benzyl CH2 AB quartet from the
1HNMR spectrum (1.2 mM, 9:1D2O:CD3OD). The quartet is centered at 5.040 ppm.
The chiral trans complex is depicted in Figure 44. The sharpness of the signals suggests
that in D2O, this complex exists as ML.
46
Figure 45 shows the optimized geometry of the cis Zn(II) complex monohydrate
(methyl ester for simplicity). The calculation was a Hartree-Fock operation performed on
Spartan ’04. It shows coordination of the carbonyl to the metal center as well as a twisted
side chain. Analysis of the coordination bond lengths reveals that the carbonyl-Zn bond
is shorter than the ligand N-Zn bonds. The pendant chain is twisted to allow for
coordination of the ester carbonyl to the metal and for the R group to adopt a
conformation to reduce steric strain. The geometry appeared to be distorted 5-coordinate
(square pyramidal). The HMQC in Figure 46 illustrates that the two protons are indeed
attached to the same carbon and are likely diastereotopic.
ppm (t1)4.9505.0005.0505.1005.150
Figure 43. 1HNMR trace of trans benzyl CH2 Zn(II) complex (J=76.6 Hz, J=12.6 Hz).
Figure 44. Chiral trans Zn(II) complex in D2O.
NN
N
R
N
N
N
R
Zn
lig
O O
H H
47
Figure 45. Molecular model of the isomerized (cis) Zn(II) complex monohydrate. Top left: ball and stick. Top right: ball and wire (hydrogens excluded). Bottom: calculated
bond distances (in Angstroms) to Zn(II).
1.893 2.099
1.9792.206
48
Figure 46. HMQC of benzyl ester (18)-Zn(II) complex.
49
Analytical methods for evaluation of the hydrolysis
An understanding of the kinetics and extent of hydrolysis was necessary in order
to maximize the desired activity. The hydrolysis was monitored by two methods:
1HNMR for Zn(II) complexes and gas chromatography for Cu(II) complexes. 1HNMR
analysis was carried out using water suppression and 128 scans. Crude NMR yields were
determined using DMSO as an internal standard. The integration of the benzyl alcohol
CH2 was compared to the integration of the starting material CH2. GC analysis was
performed by taking an aliquot of the aqueous solution and extracting the benzyl alcohol
with a solution of dilute 1-octanol internal standard in diethyl ether. Three extracts were
partially concentrated by evaporation and were analyzed by GC using single point
calibration. Generation of benzyl alcohol was quantified by its peak area compared to the
peak area of 1-octanol. The internal response factor (IRF) of 1-octanol/BnOH was found
to be 1.35. Three solutions were analyzed in triplicate and were averaged.
Photochemistry of ligand (18) and an array of metals
An experiment was devised to evaluate the performance of an array of metals
(SO42- counterion) using the same benzyl ester ligand. Ligand (18) was complexed with
each metal at 1.2 mM in 5 mL 9:1 H2O:MeOH. Each was irradiated for 30 minutes at
350 nm (Rayonet lamp) using a rotary platform. The solutions were placed in the dark
for 3 days at which point each was extracted with diethyl ether containing the 1-octanol
internal standard. Having the 1-octanol in the extractant allowed for a tunable internal
50
standard. GC analysis showed that Cu(II) outperformed the other metals, while Zn(II)
performed the worst. The results are presented in Table 8.
Table 8. Effect of metal on hydrolysis analyzed by GC.
Metal % yield BnOH Rel. Yield Zn(II) 12 1.0 Co(II) 19 1.6 Ni(II) 20 1.7 Cu(II) 32 2.7
Evaluation of ligand (18)-Zn(II) complex by 1HNMR
The Zn(II) complex (1 mL, 1.3 mM in 9:1 D2O:CD3OD) was irradiated for 30
min at 350 nm (Rayonet lamp) and was analyzed by 1HNMR. The tube was monitored
daily for production of benzyl alcohol against DMSO as an internal standard. There
appeared to be a burst or spike in hydrolysis during and just after irradiation, at which
point the rate tapered off considerably. The 1HNMR spectra indicated that there were
several forms of complexed ligand and that a small amount of some aldehyde (9.92 ppm)
was formed after irradiation. The aldehyde peak matched that of benzaldehyde. The
experiment was repeated under anaerobic conditions, attained by three freeze-pump-thaw
cycles. This would minimize or eliminate any side reactions that would have been
possible by singlet oxygen. Figure 47 shows both the aerobic and anaerobic experiments.
Degassing the solution had no positive effect on the hydrolysis or the presence of
benzaldehyde. Both experiments reached their maximum hydrolysis at the one day dark
time point.
51
0
2
4
6
8
10
12
14
16
0 0.5 1 1.5 2 2.5 3
days dark after 30 min hv
% B
nOH
X345b aerobicX356 anaerobic
Figure 47. Zn(II) complex hydrolysis monitored by 1HNMR.
The effect of excess light exposure was studied with the Zn(II) complex. It did
not have any positive effect on hydrolysis. One NMR tube sample was irradiated for 30
minutes and was followed over 2 hours in the dark. The other tube was irradiated for up
to two hours and monitored. Figure 48 below illustrates the two experiments. The
hydrolysis efficiency seemed to be suppressed by the excess irradiation.
52
0
1
2
3
4
5
6
7
8
9
10
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
hours (light or dark)
% B
nOH
light tubedark tube
Figure 48. Crude NMR yield of Zn(II) complex / effect of excess light exposure.
Likewise, under-exposure to light was also examined (Figure 49). Three samples
were prepared and were irradiated for 5, 10, and 15 minutes. The NMR tubes were
monitored initially and daily out to 3 days in the dark. Decreasing the exposure to light
did not have any positive effect on hydrolysis. Hydrolysis was proportional to irradiation
time and did not fluctuate much over the dark time. GC analysis of the Zn(II) complex
extract confirmed that the hydrolysis was no greater than 15 % at 6 days in the dark.
53
0
1
2
3
4
5
6
7
8
9
10
0 0.5 1 1.5 2 2.5 3
days dark
% B
nOH 5 min light
10 min light15 min light
Figure 49. Effect of light exposure on hydrolysis over time.
Evaluation of ligand (18)-Cu(II) complex by gas chromatography
The Cu(II) complex showed more promising results. The 1.2 mM complex (12.5
mg ligand scale, 1.15 equivalents of metal) was irradiated for 30 minutes and was
monitored by GC daily for six days. The hydrolysis leveled off after two days dark,
reaching approximately 50 % completion. A degassed reaction was also evaluated and
the results are shown in Figure 50. Anaerobic conditions seemed to favor an increase in
hydrolysis and the highest amount of hydrolysis approached 70 %. A GC experiment
with the Cu(II) complex showed no significant increase in hydrolysis with excess light
exposure.
54
0
10
20
30
40
50
60
70
80
0 1 2 3 4 5 6 7 8
days dark
% B
nOH
by
GC
X354 aerobicX357 anaerobic
Figure 50. Cu(II) complex hydrolysis monitored by GC.
Dark control experiments
An important pair of experiments showed that no hydrolysis occurred without
irradiation. The un-irradiated Zn(II) complex was monitored by 1HNMR, indicating no
hydrolysis at 4 and 8 days dark. The un-irradiated Cu(II) complex was monitored by gas
chromatography, indicating trace 3-5 % hydrolysis in the dark at 3 and 7 days. These
results indicate that the observed hydrolysis is a dependent upon irradiation.
55
Preparative scale experiments with Zn(II) and Cu(II) complexes
The initial pH was approximately 5.5. The complexes were degassed by bubbling
Ar through a needle for 1.5 hours, then irradiated at 350 nm (Rayonet lamp) while
stirring. The pH remained 5.5 and the color became more intense after irradiation.
Figure 51 illustrates the color observed for the Cu(II) complexes after irradiation. The
complexes were stirred in the dark for 6 days at which point each complex was extracted
multiple times with diethyl ether to recover benzyl alcohol from the hydrolysis. The
extracts were dried over anhydrous MgSO4 and concentrated on a rotary evaporator (no
heat bath). The aqueous solutions were stirred with 2.5 equivalents of EDTA disodium
salt overnight to displace the ligand from the metal. The solution was extracted with
CH2Cl2, dried, and concentrated. The material was analyzed by 1HNMR.
Figure 51. From left to right: benzyl, 4-methoxy benzyl, menthyl, phenethyl, ethyl valerate. (Cu(II) complexes after irradiation)
Figure 52 and Table 9 show results for the final optimized conditions, where the
complex (1.2 mM in 39:1 H2O:MeOH, or 97.5 % : 2.5 % by volume) was degassed for
1.5 hours, irradiated for 7 hours, and stirred in the dark for 6 days. The Zn(II) complex
56
yielded 31 % benzyl alcohol. Analysis of the ligand material indicated much
photodegradation, while some trans and cis ligand were detected. Benzaldehyde (3 %)
was detected in both the ether and CH2Cl2 extracts.
The same conditions with the Cu(II) complex gave 52 % benzyl alcohol by
isolated yield. Analysis of the remaining ligand material indicated that all but a trace of
the material had been photoisomerized and all but 2 % of the cis ligand had been
hydrolyzed. The methyl ester byproduct was reduced almost proportionally to the
amount that the MeOH was reduced. It is interesting to note that the methyl ester was
only detected with the Cu(II) complex and benzaldehyde was detected only with the
Zn(II) complex. The photoisomerization appears to occur more rapidly with the Zn(II)
complex, while the hydrolysis appears to be more rapid in the case of the Cu(II) complex.
The cis acid (byproduct of hydrolysis) was observed in the case of Cu(II), but not with
Zn(II).
N
NN
OOR
CuN
NN
O ORCu
350 nm hv
N
NN
O OHCu + ROH
dark
7 h 6 d
Figure 52. General scheme for optimized photochemistry and hydrolysis.
57
Table 9. Prep scale isolated yield results (0.239 mmol ligand, 1.15 eq. Cu(II))
HO
HO
HO
58
methoxybenzaldehyde. A low total recovery (44 %) was achieved. The ethyl valerate
analogue had mediocre performance, as only 42 % of the known ethyl 5-hydroxyvalerate
was recovered (FAB-MS calculated for C7H14O3Li+: 153.1103. Found: 153.1106). Only
5 % EtOH was isolated, indicating that the hydrolysis takes place mainly at the ester near
the alkene. The experiment using 5 equivalents of Cu(II) resulted in twice the amount of
hydrolysis of the ethyl ester and only 44 % hydrolysis of the valeric ester. Here, a
significant amount of cis ligand was recovered, indicating a slow hydrolysis.
In the case of the menthyl analog, only 5 % L-(-) menthol was isolated. The
hydrolysis is very slow and the photoisomerization was incomplete, as 51 % cis ligand
and 17 % trans ligand were isolated. The experiment using 5 equivalents of Cu(II)
resulted in approximately the same amount of poor hydrolysis and a significant amount
of recovered ligand. There appears to be an issue with incomplete complexation, even
with excess metal. Some amount of cis acid and methyl ester was recovered as well with
the following exceptions: the Zn(II) experiments gave no methyl ester ligand but
benzaldehyde generation was unique, and the 5 equivalent Cu(II) experiment gave no
methyl ester. A dark control experiment with Cu(II) indicated that the activity is truly
photoactivated, as only a trace of benzyl alcohol was identified.
UV-Vis binding titrations
In the case of the prep scale experiments using 1.15 equivalents of Cu(II), no
more than 73 % of the material was accounted for. To evaluate the possibility of a
possible ML2 complex, several binding titrations were performed. These experiments
exploited the absorption band around 368 nm that is unique to the Cu(II)-ligand complex.
59
In the sample cuvette, 1.5 mL of a 24 µm CuSO4 solution in MeOH was titrated with the
ligand in MeOH. From a plot of the ligand/metal ratio against the change in absorbance,
a value for the ligand/metal ratio could be extracted. This was achieved by finding the
intersection of the two trend lines. Figure 53 below shows the results for the benzyl ester
(18). Figure 54 shows the data for the analogues. The methylated ligand (15) was
included to investigate the effect of the ester moiety. All of the data are consistent with a
significant amount of ML2. The ligand to metal ratio for the ester analogs ranged from
1.5 to 2.2. The amide complexes gave the ratios 2.1 and 2.2.
Figure 53. UV-Vis binding titration curve for the benzyl ester-Cu(II) complex.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50
ligand/Cu ratio
delta
Abs
NN
N
R
N
N
N
R
Cu
proposed
Mole ratio ligand/Cu(II) = 1.8
60
lig
lig
lig
OMe
lig
O
O
lig1.7
1.5
1.8
Cu(II) 1.8Zn(II) 2.2
Cu(II) 2.2Zn(II) 2.1
NNN
1.6
Benzyl amide Cu(II) 2.2Zn(II) 2.1
Figure 54. UV-Vis binding titration results (ligand/metal ratio).
Burst hydrolysis
The slow hydrolysis data from the isolated yields and the binding titration data
suggest that fast hydrolysis is dependent upon the concentration of ML (Figure 55). A
slow equilibration of ML with ML2 is likely the rate determining step over the 6 days
(Figure 56).
esterhydrolysis
H2O
fastML
slow
slowM(L)2
Figure 55. Proposed hydrolysis scheme.
There appears to be a burst in hydrolysis over the initial irradiation time. This
likely corresponds to the hydrolysis of the ML complex present. Subsequent
61
equilibration from ML to ML2 and back corresponds to the observed slow hydrolysis. An
experiment was devised to compare the initial burst hydrolysis with a gradient of Cu(II).
A complex of benzyl ester ligand (18) and Cu(II) (1:1 ratio, 1.2 mM in 9:1 H2O:MeOH,
25 mL) was stirred and irradiated for 30 minutes. A 5.00 mL aliquot was withdrawn,
combined with 100 µL 0.006M 1-octanol in Et2O, and extracted with 3 x 5 mL Et2O.
The extract was evaporated to approximately 0.2 mL with a stream of air. Analysis by
GC using a single-point calibration gave the extent of hydrolysis. This was repeated for
three other solutions, using 2, 5, and 10 equivalents of Cu(II). Dark controls showed
minimal activity. 5 equivalents of Cu(II) provided the largest burst of hydrolysis, around
12 %. 0.5 eq of Cu(II) shut down the burst, most likely due to a tight 2:1 ligand:metal
complex formation.
0
2
4
6
8
10
12
14
0.5 1 2 5 10
eq. Cu(II)
% h
ydro
lysi
s im
med
iate
ly a
fter 3
0 m
in li
ght
30 min lightdark control
Figure 56. Burst hydrolysis as a function of Cu(II).
Effect of pyridine additive
The data suggests that another ligand binding group may be needed to inhibit ML2
complexation and increase the concentration of the ML complex for a faster hydrolysis.
62
This was evaluated with the existing ligand and pyridine as a binding additive. One
equivalent would be expected to give a square planar complex, while three equivalents
would likely give an octahedral complex (Figure 57). The experiments were monitored
by GC over the course of 4 days (1.2 mM, 25 mL, Figure 58). The pH of the complex
with 3 eq pyridine was found to be 5.87, as compared to 5.40 without the additive. 1 eq
pyridine gave a pH of 5.66. At 30 minutes of irradiation, 3 eq of pyridine gave a pH of
5.74, as compared to 4.47 without the additive. The pyridine additive gave an increase in
the initial burst of hydrolysis after 30 minutes of light (350 nm Rayonet). The hydrolysis
reached completion much earlier than in the experiment without the additive. In addition
to a faster hydrolysis, the pyridine additive gave an increase in the extent of hydrolysis,
reaching nearly 70 %. The pyridine additive reduced the total dark hydrolysis time from
six days to one day, which supports the hypothesis about fast ML complex hydrolysis.
The increase in pH with the additive may also influence the hydrolysis. An experiment
was carried out using 1 equivalent of 2,6-ditert-butyl-pyridine, which provided the same
pH (5.68), but no binding capability. The pH effect alone did not speed up the hydrolysis
when compared to the GC experiment without an additive. This indicates that the next
generation of ligand would need to be functionalized with an additional binding group.
NN
NN
N
N
Cu
O
ORN
NN
Cu
O
OR
N
Figure 57. Proposed effect of pyridine additive (1 equivalent and 3 equivalents).
63
0
10
20
30
40
50
60
70
80
0 1 2 3 4
days dark
% h
ydro
lysi
s
1 eq pyr light3 eq pyr light1 eq pyr dark3 eq pyr darkno additive1 eq tBu pyr light1 eq tBu pyr dark
Figure 58. Effect of pyridine additive on ester hydrolysis.
A prep scale experiment was carried out to validate the GC results. 100 mg of
ligand (18) and 3 eq of pyridine in MeOH were slowly added to a stirring solution of 1.15
eq CuSO4 in H2O (1.2 mM). The solution was degassed for 2 hours and irradiated at 350
nm (Rayonet lamp) for 7 hours. One half of the solution was extracted with diethyl ether
at 14 hours of dark time, indicating 77 % hydrolysis. The same result was obtained for
the portion stirring for 3 days in the dark. Only 4-8 % of cis acid material was recovered
from the EDTA treatment.
64
Evaluation of an amide
The benzyl amide ligand was prepared by Horner-Emmons olefination. The
Horner-Emmons reagent (27) was assembled in 97 % yield by DCC coupling of diethyl
phosphonoacetic acid with benzylamine (Figure 59). The anionic Horner-Emmons
reagent was reacted with aldehyde (16) to give alkene (28) in 52 % yield (Figure 60).
PO
OO
PO
OO
O
OH
O
NH
CH2Cl2
DCC, DMAP
BnNH2
Figure 59. Preparation of the benzyl amide Horner-Emmons reagent (27).
NNN
O
NNN
O NHBn
PO
(EtO)2
NaH, DMF
O
NHBn
(16) (28)
(27)
Figure 60. Synthesis of the benzyl amide ligand.
The UV-Visible spectra for the benzyl amide ligand (28), Zn(II) complex, and
Cu(II) complex are shown below in Figures 61-63. The spectra closely match those of
the benzyl ester previously discussed. Tables 10a-c detail the absorbance and molar
absorptivity data from the spectroscopic measurements.
65
-0.1
0.1
0.3
0.5
0.7
0.9
1.1
1.3
1.5
250 270 290 310 330 350 370 390 410
wavelength (nm)
abso
rban
ce B, 4.5 x 10-5 MC 2.25 x 10-5 MD, 1.12 x 10-5 M
Figure 61. UV-Vis spectrum of benzyl amide ligand (28) in MeOH.
-0.1
0.1
0.3
0.5
0.7
0.9
250 270 290 310 330 350 370 390 410
wavelength (nm)
abso
rban
ce B, 4.5 x 10-5 MC 2.25 x 10-5 MD, 1.12 x 10-5 M
Figure 62. UV-Vis spectrum of the benzyl amide-Zn(II) complex in H2O.
66
-0.1
0.1
0.3
0.5
0.7
0.9
1.1
1.3
1.5
250 270 290 310 330 350 370 390 410
wavelength (nm)
abso
rban
ce B, 4.5 x 10-5 MC 2.25 x 10-5 MD, 1.12 x 10-5 M
Figure 63. UV-Vis spectrum of the benzyl amide Cu(II) complex in H2O.
Tables 10a-c. UV-Vis data for benzyl amide ligand (28) and complexes.
a) Ligand Concentration (M) Abs350 nm Є (L mol-1 cm-1)
350 nm Abs366 nm Є (L mol-1 cm-1)
366 nm 4.50 x 10-5 0.178 4000 0 0 2.25 x 10-5 0.0774 3400 0 0 1.12 x 10-5 0.0389 3500 0 0
b) Zn(II) complex Concentration (M) Abs350 nm Є (L mol-1 cm-1)
350 nm Abs366 nm Є (L mol-1 cm-1)
366 nm 4.50 x 10-5 0.403 9000 0.445 9900 2.25 x 10-5 0.198 8800 0.221 9800 1.12 x 10-5 0.0776 6900 0.086 7700
c) Cu(II) complex Concentration (M) Abs350 nm Є (L mol-1 cm-1)
350 nm Abs366 nm Є (L mol-1 cm-1)
366 nm 4.50 x 10-5 0.417 9300 0.418 9300 2.25 x 10-5 0.192 8600 0.194 8600 1.12 x 10-5 0.0780 7000 0.0800 7100
67
The photoisomerization of the alkene was studied in the same way as the ester
ligand (18). The ligand was complexed with 1.0 equivalents of ZnSO4 in 9.6 mM 9:1
DMSO-d6:D2O. The solvent system was necessary for a concentration that corresponded
to a reasonable number of NMR scans. The solution was irradiated at 350 nm (Rayonet
lamp) in intervals up to 40 minutes and the benzyl CH2 peak and alkene doublets were
monitored for disappearance of trans and the appearance of cis complex (Figure 64). The
peaks were broadened as seen with benzyl ester (18) due to the DMSO solvent
environment and fast exchange at the metal center. The conformational change appears
to be complete around 30 minutes, giving rise to a broad AB quartet. The diastereotopic
CH2 suggests that the Zn(II) complex is chiral, just as was observed with the ligand (18)-
Zn(II) complex.
t=0
t=5 min
t=8 min
t=13 min
t=20
min
ppm (t1 4.25 4.50 . 7 5t=40 min F i g u r e 6 4 . P h o t o i s o m e r i z a t i o n
o f l i g a n d ( 2 8 ) - Z n ( I I ) c o m p l e x .
68
An initial experiment was performed with the benzyl amide (28) and each of the
two metals, Zn(II) and Cu(II). The complexes were prepared at 0.96 mM in 9:1
H2O:MeOH. The amide complex was generally less soluble in the solvent system than
the complexed ester at standard 1HNMR concentrations (approx. 10 mM). They were
irradiated for 30 minutes and then stirred in the dark for 5 days. The solutions were
analyzed by gas chromatography at 4 and 5 days of dark time (aliquots were extracted
multiple times with diethyl ether and the ether was concentrated). Benzylamine was not
detected in the ether extracts. If any benzylamine was liberated, it is possible that it
remained coordinated to the metal. It is also possible that the amide bond, stronger than
an ester linkage (due to resonance stability), did not hydrolyze at all.
A preparative scale reaction confirmed the negative results (Figure 65). 0.239
mmol of ligand was complexed with 5 equivalents of Cu(II), irradiated for 7 hours at 350
nm (Rayonet lamp) and stirred in the dark for 6 days. The aqueous solution (adjusted
with saturated aqueous sodium bicarbonate to pH=10) was extracted multiple times with
both diethyl ether and dichloromethane, yielding no benzylamine. The aqueous complex
was stirred with 8 equivalents of EDTA disodium salt overnight at which point multiple
extractions with dichloromethane yielded no benzylamine, only ligand material. 66 % of
the ligand material was accounted for, while a total of 29 % was the trans ligand and 37
% was the cis ligand. Under these conditions, incomplete photoisomerization and no
hydrolysis were observed. As shown previously in Figure 54, the benzyl amide ligand
(28) titrated into Cu(II) and Zn(II) gave similar mole ratios of ligand to metal (2.2 and 2.1,
respectively).
69
NN
N
O NHBn
5 eq. CuSO4H2O
7 hr 350 nm hv6 days dark
NN
N
O NHBn
NN
N+
29 % 37 %
O
NHBn
1) Et2O extract
2) XS EDTA CH2Cl2 extract
Figure 65. Scheme for the prep scale benzyl amide-Cu(II) complex photolysis.
One last attempt was made with the benzyl amide, this time using 3 equivalents of
pyridine. A preparative scale experiment (100 mg ligand, 1.15 eq Cu(II)) was degassed
1.5 hr, irradiated for 7 hr, and stirred in the dark for 7 days. Using the basic workup
described above, no benzylamine was recovered. A total of 55 % of the substrate
material was recovered (36 % cis, 24 % trans). This data shows that the current ligand
with or without the pyridine additive does not undergo photoactivated amide hydrolysis.
Conclusion
A new type of metalloesterase has been built that selectively releases alcohols in
the presence of metal and light in aqueous solution. Several prototypes were assembled,
the final being a tridentate ligand. Release of the alcohol is not a photo-hydrolysis, but is
dependent upon isomerization of a trans alkene to the cis isomer. Hydrolysis was more
efficient when the ligand to metal ratio was 1:1. Binding titrations showed that the ratio
was closer to 2:1, leading to a slow hydrolysis over several days. Binding additives (to
exclude 2:1 complexation) allowed for a more efficient hydrolysis within 14 hours.
Recovered alcohol yields up to 86 % were observed with the ligand-Cu(II) system.
70
REFERENCES
1. Taylor, C. M.; Watton, S.P.; Flurie, A.; Ricketts, J.I. “Speciation of Ternary Cobalt(II) Phenanthroline-Silica Surface Complexes as a Function of pH and Ligand Steric Bulk,” Inorg. Chem. 2003, 42, 7381-7386.
2. Dong, L.C., “The synthesis, characterization and investigation of
phenanthrolinylporphyrins,” Ph.D. Dissertation, Princeton University: 1991.
3. Gordon, A.J., Ford, R.A., The Chemist’s Companion: A Handbook of Practical Data, Techniques, and References. Wiley: New York, 1972.
4. Zhang, T., Anslyn, E.V., “Molecular recognition and indicator-displacement
assays for phosphoesters,” Tetrahedron. 2004, 60, 11117-11124.
5. Hicks, R. G., Koivisto, B. D., Lemaire, M. T., “Synthesis of Multitopic Verdazyl Radical Ligands. Paramagnetic Supramolecular Synthons,” Org. Lett. 2004, 6, 1887-90.
6. Schubert, U. S.; Eschbaumer, C.; Heller, M. “Stille-Type Cross Coupling-An
Efficient Way to Various Symmetrically and Unsymmetrically Substituted Methyl-Bipyridines: Toward New ATRP Catalysts,” Org. Lett. 2000, 2, 3373-3376.
7. Angeloff, A.; Daran, J-C.; Bernadou, J.; Meunier, B., “The Ligand 1,10-
Phenanthroline-2,9-dicarbaldehyde Dioxime can Act Both as a Tridentate and as a Tetradentate Ligand 2 Synthesis, Characterization and Crystal Structures of its Transition Metal Complexes,” Eur. J. Inorg. Chem. 2000, 1985-1996.
8. Chandler, C. J., Deady, L.W., Reiss, J.A., “Synthesis of some 2,9-disubstituted-
1,10-phenanthrolines,” J. Het. Chem. 1980, 18, 599-601.
71
EXPERIMENTAL
General
All reagents and solvents were purchased from commercial sources or prepared as
described in the following pages. Melting points were determined with a Mel-Temp II
instrument and are reported uncorrected. Thin layer chromatography was performed on
silica gel or basic alumina (250 µm thick aluminum or plastic-backed plates doped with
fluorescein). The chromatograms were visualized with UV light (254 nm or 365 nm).
Column chromatography was carried out with silica gel (60 Ǻ) or basic alumina (150
mesh, Brockmann I, 58 Ǻ). 1H and 13C-NMR spectra were performed on a Bruker
Avance 300 MHz or 500 MHz NMR spectrometer (as indicated). Photochemical
reactions were conducted with either a 450 W medium pressure Hg vapor lamp with a
uranium oxide doped glass filter (366nm) or in a Rayonet reactor equipped with sixteen
Hg vapor lamps (350 nm). Long wavelength visible light experiments were carried out
using a slide projector fitted with a filter for light <600 nm. UV-Visible spectra were
obtained on a HP 8453 scanning spectrometer. IR spectra were obtained using a Mattson
Genesis II FTIR spectrometer. Elemental analyses were performed by Atlantic Microlab,
Norcross, GA. HRMS analysis was performed at Old Dominion University, Norfolk, VA.
The samples were dissolved in 1:1:1 THF:MeOH:MeCN with NaCl and were analyzed
by positive ion electrospray on a Bruker 12T Apex-Qe FTICR-MS with an Apollo II
source. X-Ray crystallographic analysis was performed in-house (see Appendix A).
72
Mono-substituted 1,10-phenanthroline ligands
NN
NN
2-methyl-1,10-phenanthroline (1). 1.70 g (9.43 mmol) 1,10-phenanthroline and 2.7 g
DABCO (24.1 mmol) were added to 120 mL anhydrous benzene and the reaction mixture
was chilled over salt and ice to achieve a temperature of 5-10 °C. 22.5 mL of
methyllithium (1.6 M in diethyl ether) was added dropwise, resulting in a dark solution.
The reaction was warmed to room temperature at which time 24 mL of saturated aqueous
ammonium chloride was added, resulting in a biphasic system. The aqueous layer was
collected and extracted with 3 x 50 mL diethyl ether. The organic extracts were washed
with 3 x 100 mL brine and concentrated under vacuum. The crude product was dissolved
in 400 mL CH2Cl2. 300 mL water, 300 mL household bleach, and 0.36 g Aliquat 336
phase transfer catalyst were added to the organics. The solution was stirred vigorously
overnight. The product was purified by column chromatography (silica gel, 60 % ethyl
acetate, 38 % hexanes, and 2% triethylamine), yielding 1.26 g (68.8 %). 1H-NMR (300
MHz, CDCl3) δ 9.21 (dd, 1H, J=1.6 Hz, J=4.3 Hz), 8.22 (dd, 1H, J=1.7 Hz, J=8.1 Hz),
8.12 (d, 1H, J=8.2 Hz), 7.73 (d, 2H, J=3.9 Hz), 7.60 (dd, 1H, J=4.4 Hz, J=8.1 Hz), 7.51 (d,
1H, J=8.2 Hz), 2.96 (s, 3H) ppm.1
73
NN
NN
CHO
1,10-phenanthroline-2-carboxaldehyde (2). 1.68 g 2-methyl-1,10-phenanthroline (8.65
mmol), 6.9 g SeO2 (62.3 mmol), and 200 mL 1,4-dioxane were refluxed for 45 minutes.
The reaction solution was filtered while hot and was concentrated under vacuum. The
yellow solid was dissolved in 200 mL CH2Cl2 and 200 mL water. The organics were
washed with 200 mL water and 100 mL brine. The aqueous layer was extracted with 3 x
100 mL CH2Cl2. The organics were dried over anhydrous Na2SO4 and concentrated
under vacuum, yielding 1.36 g product (75.6 %). 1H-NMR (300 MHz, CDCl3) δ 10.58 (s,
1H), 9.31 (dd, 1H, J=1.7 Hz, J=4.4 Hz), 8.45 (d, 1H, J=8.2 Hz), 8.33 (m, 2H), 7.93 (dd,
2H, J=8.9 Hz, J=22.5 Hz), 7.74 (dd, 1H, J=4.4 Hz, J=8.1 Hz) ppm.2
NN
CHO
NN
OOMe
1,10-phen ligand methyl ester (3). 1.36 g 1,10-phenanthroline-2-carbaldehyde (6.53
mmol), 2.40 g Ph3P=CHCO2Me (7.18 mmol), and 250 mL anhydrous benzene were
refluxed for 16 hours. The reaction mixture was concentrated under vacuum and the
74
product was purified by column chromatography (silica gel, 10 % acetone in CHCl3);
1.66g (96.5 %). 1H-NMR (300 MHz, CDCl3) δ 9.25 (dd, 1H, J=1.7Hz, J=4.4 Hz), 8.26
(m, 3H), 7.92 (d, 1H, J=8.3 Hz), 7.81 (d, 2H, J=1.7 Hz), 7.66 (m, 1H), 7.03 (d, 1H,
J=16.1 Hz), 3.86 (s, 3H) ppm. 13C-NMR (125 MHz, CDCl3) δ 166.7, 153.2, 150.3, 145.9,
145.8, 144.8, 136.5, 135.9, 128.8, 128.4, 127.2, 126.0, 123.1, 123.0, 121.2, 51.7 ppm.
λmax (MeOH) 291, 358 nm. MP=108-110 °C. HRMS calculated for C16H12N2O2Na+:
287.079099. Found: 287.079348.
NN
CHO
NN
OOBn
1,10-phen ligand benzyl ester (4). 0.50 g 1,10-phenanthroline-2-carbaldehyde (2.4
mmol), 1.08 g Ph3P=CHCO2CH2Ph (2.6 mmol), and 100 mL dry benzene were refluxed
under argon for 15 hours. The crude mixture was concentrated under vacuum and
chromatographed on silica gel (7% acetone in CHCl3), yielding 0.82 g tan solid (99.3 %).
1H-NMR (300 MHz, CDCl3) δ 9.23 (dd, 1H, J=1.6 Hz, J=4.3 Hz), 8.26 (m, 3H), 7.89 (d,
1H, J=8.3 Hz), 7.79 (d, 2H, J=1.5 Hz), 7.64 (dd, 1H, J=4.3 Hz, J=8.0 Hz), 7.41 (m, 5H),
7.05 (d, 1H, J=16.1 Hz), 5.30 (s, 2H) ppm. 13C-NMR (125 MHz, CDCl3) δ 166.1, 153.3,
150.4, 146.0, 145.9, 145.1, 136.6, 136.0, 135.7, 128.9, 128.5, 128.4, 128.1, 127.3, 126.0,
75
123.3, 123.1, 121.2, 66.4 ppm. λmax (MeOH) 292, 358 nm. MP=114-116 °C. HRMS
calculated for C22H16N2O2Na+: 363.110399. Found: 363.110620.
General procedure for yield determination by gas chromatography. Yields of benzyl
alcohol (boiling point 203-205 °C) were measured using an Agilent 6890 Series gas
chromatograph with an FID detector. The column used was an Agilent HP-5 (5 %
phenyl)-polymethylsiloxane column (30 m, 250 µm, He carrier gas). The method
parameters are as follows: 50 °C for 1 minute and a ramp of 5 °C/minute to 200 °C for 14
minutes (RBnOH=6.7 min, R1-octanol=7.7 min). A calibration curve was established using 1-
octanol (boiling point 196 °C) as an internal standard. The standard injections were
comprised of benzyl alcohol and 1-octanol in the following ratios (1:4, 1:2, 1:1, 2:1, and
4:1). Approximately 5 µL of the ethyl acetate extraction layer was injected for analysis.
The peak area ratio of the analyte and standard was obtained via electronic integration,
allowing for the calculation of percent yield benzyl alcohol.
Pyridine ligands
NHO OH
NOTsHO
2,6-pyridinedimethanol monotosylate (5). 2.00 g of commercially-available 2,6-
pyridinedimethanol (14.4 mmol), 5.68 g of Ag2O (24.5 mmol), 0.48 g KI (2.90 mmol),
and 100 mL CH2Cl2 were chilled to -20 °C under an Ar blanket. 3.00 g of p-
toluenesulfonyl chloride (15.7 mmol) was added and the solution warmed to room
temperature for 3 hours. The dark brown suspension was then filtered through a silica gel
76
plug and rinsed with 300 mL ethyl acetate, which was concentrated under vacuum. The
product was purified by chromatography (silica, CH2Cl2, then ethyl acetate), yielding
2.58 g pink viscous oil (75 %). 1H-NMR (300 MHz, CDCl3) δ 7.83 (d, 2H, J=8.4 Hz),
7.69 (t, 1H, J=7.8 Hz), 7.34 (t, 3H, J=7.8 Hz), 7.17 (d, 1H, J=7.8 Hz), 5.14 (s, 2H), 4.70
(s, 2H), 2.45 (s, 3H) ppm.3
NOTsHO
NN
OH
O
O
Pyridine-2-methanol-bis-methoxyethyl-6-methylamine (6). 0.50 g 2,6-
pyridinedimethanol monotosylate (1.70 mmol), 0.262 mL bis(2-methoxyethyl)amine
(1.79 mmol), 20 mL dry acetone, and 0.247 g anhydrous K2CO3 (1.79 mmol, charged last)
were refluxed for 4 hours. The reaction solution was concentrated under vacuum and re-
dissolved in CHCl3. The insoluble salts were filtered off and the organics were washed
with 4 x 15 mL H2O. The organic layer was concentrated, yielding 0.36 g product (83.6
%). 1H-NMR (300 MHz, CDCl3) δ 7.64 (t, 1H, J=7.6Hz), 7.41 (d, 1H, J=7.7Hz), 7.07 (d,
1H, J=7.6Hz), 4.73 (s, 2H), 3.91 (s, 2H), 3.50 (t, 4H, J=5.9Hz), 3.32 (s, 6H), 2.82 (t, 4H,
J=5.9Hz) ppm. 13C-NMR (125 MHz, CDCl3) δ 158.9, 158.2, 136.9, 121.2, 118.4, 71.0,
63.9, 60.8, 58.6, 54.0. HRMS calculated for C13H22N2O3Na+: 277.152264. Found:
277.152242.
77
NN
NN
OH
O
O
O
OO
Pyridine-2-carboxaldehyde-bis-methoxyethyl-6-methylamine (7). 20 mL dry CH2Cl2
was chilled to -78 °C over dry ice, at which time 0.203 mL oxalyl chloride (2.36 mmol)
and 0.279 mL anhydrous DMSO (3.93 mmol) were added slowly and allowed to stir for 5
minutes. 0.50 g (1.97 mmol) of amine (6) in 5 mL CH2Cl2 was added slowly and the
reaction was stirred 30 minutes. 1.1 mL triethylamine (7.86 mmol) was added and the
reaction was warmed to room temperature, where 50 mL H2O was added. The phases
were separated and the H2O layer was extracted with 2 x 20 mL CH2Cl2. The organics
were washed with 3 x20 mL H2O, dried over MgSO4, and concentrated under vacuum,
yielding 0.36 g brown oil (72.6 %)4. 1H-NMR (300 MHz, CDCl3) δ 10.06 (s, 1H), 7.83 (s,
3H), 4.00 (s, 2H), 3.51 (t, 4H, J=5.8Hz), 3.31 (s, 6H), 2.85 (t, 4H, J=5.8Hz) ppm. 13C-
NMR (75 MHz, CDCl3) 193.2, 161.1, 151.6, 136.9, 126.9, 119.6, 70.7, 60.5, 58.3, 53.9.
HRMS calculated for C13H20N2O3Na+: 275.136614. Found: 275.137230.
NN N
N
OBn
O
O
O
O
OO
Pyr-methoxy benzyl ester ligand (8). 186 mg of NaH (60 % dispersion in mineral oil,
4.65 mmol) dissolved in 20 mL dry THF was added slowly to a solution of 1.08 g benzyl
diethylphosphonoacetate (3.77 mmol) in 20 mL THF. After stirring 10 minutes, 1.00 g
(4.00 mmol) of aldehyde (7) was added slowly, at which point the reaction was stirred for
78
1 hour. 80 mL of saturated aqueous NH4Cl solution was added. The THF was removed
under vacuum and the remaining water layer was extracted with 3 x 100 mL CHCl3. The
extract was washed with 3 x 100 mL H2O, dried over MgSO4, and concentrated under
vacuum. The product was purified by chromatography (basic Al2O3, 7:3 hexanes:ethyl
acetate + 2 % triethylamine), yielding 0.78 g yellow oil (53.8 %). 1H-NMR (300 MHz,
CDCl3) δ 7.68 (m, 2H), 7.51 (d, 1H, J=7.7Hz), 7.39 (m, 5H), 7.28 (s, 1H), 6.97 (d, 1H,
J=15.7Hz), 5.26 (s, 2H), 3.90 (s, 2H), 3.49 (t, 4H, J=5.9Hz), 3.31 (s, 6H), 2.82 (t, 4H,
J=5.9Hz) ppm. 13C-NMR (125 MHz, CDCl3) δ 166.6, 160.8, 151.8, 144.1, 136.9, 135.9,
128.5, 128.2, 123.7, 122.3, 121.6, 71.1, 66.4, 61.1, 58.7, 54.2 ppm. λmax (MeOH) 254,
295 nm. Analysis calculated for C22H28N2O4: C 68.73, H 7.34, N 7.29. Found: C 68.47,
H 7.30, N 7.21.
NOTsHO
NN
N
N
OH
6-methanol-tris-(2-pyridylmethyl)amine (9). 3.00 g 2,6-pyridinedimethanol
monotosylate (10.2 mmol), 1.415 mL di(2-picolyl)amine (7.86 mmol), 100 mL dry
acetone, and 1.14 g anhydrous K2CO3 (8.25 mmol, added last), were refluxed for 3.5
hours. The acetone was removed under vacuum and the material was re-dissolved in 50
mL CHCl3 and 200 mL H2O. The organics were washed with 7 x 100 mL H2O, dried
over MgSO4, and concentrated under vacuum, yielding 2.78 g yellowish/brown oil (85.0
%). 1H-NMR (300 MHz, CDCl3) δ 8.53 (d, 2H, J=4.8 Hz), 7.65 (m, 5H), 7.43 (d, 1H,
J=7.6 Hz), 7.13 (m, 3H), 4.73 (s, 2H), 3.89 (s, 6H) ppm.5
79
NN
N
N
NN
N
N
OH O
6-carboxaldehyde-tris-(2-pyridylmethyl)amine (10). 0.894 mL oxalyl chloride (10.4
mmol) in 100 mL dry CH2Cl2 was chilled to -78 °C, at which point 1.25 mL anhydrous
DMSO (17.3 mmol) was added slowly. 2.78 g (8.68 mmol) of alcohol (9) dissolved in 30
mL CH2Cl2 was added slowly and the reaction was stirred for 1 hour. 4.8 mL
triethylamine (3.47 mmol) was added slowly and the reaction was warmed to room
temperature. 100 mL H2O was added and the water layer was extracted with 3 x 25 mL
CHCl3. The organics were washed with 3 x 100 mL H2O, dried over MgSO4, and
concentrated, yielding 1.78 g brown oil (64.5 %)4. 1H-NMR (300 MHz, CDCl3) δ 10.06
(s, 1H), 8.55 (dq, 2H, J=4.8 Hz, J=0.8 Hz), 7.83 (s, 3H), 7.64 (m, 2H), 7.56 (d, 2H,
J=7.76 Hz), 7.16 (m, 2H), 3.96 (m, 5H), 3.70 (s, 1H) ppm.6
NN
N
N
NN
N
N
OBn
OO
Tris-(2-pyridylmethyl)amine ligand benzyl ester (11). 3.00 g benzyl
diethylphosphonoacetate (10.5 mmol) dissolved in 20 mL dry THF was slowly added to
0.460 g of NaH (11.5 mmol) in 20 mL THF. 3.50 g (11.0 mmol) of aldehyde (10) in 60
80
mL THF was added slowly and stirred 3.5 h at room temperature. 100 mL of saturated
aqueous NH4Cl was added and the solvent was removed under vacuum. 50 mL CHCl3
was added and the water layer was extracted with 3 x 30 mL CHCl3. The organics were
washed with 4 x 50 mL H2O, dried over MgSO4, and concentrated under vacuum.
Residual benzyl diethylphosphonoacetate was removed by stirring the neat crude product
in 100 mL H2O overnight and decanting. Two additional triturations were performed for
1 hour. The oil was taken up in CH2Cl2 and dried over MgSO4. The product was
purified by chromatography (basic Al2O3, 4:6 acetone:hexanes + 2 % triethylamine),
yielding 4.71 g yellow oil (50.5 % yield). 1H-NMR (300 MHz, CDCl3) δ 8.52 (d, 2H,
J=4.4 Hz), 7.62 (m, 7H), 7.39 (m, 5H), 7.25 (d, 1H, J=6.36 Hz), 7.13 (m, 2H), 6.97 (d,
1H, J=15.7Hz), 5.26 (s, 2H), 3.90 (s, 2H) ppm. 13C-NMR (125 MHz, CDCl3) δ 166.6,
159.7, 159.1, 152.0, 149.1, 143.8, 137.0, 136.4, 135.9, 128.5, 128.2, 123.6, 122.9, 122.5,
122.0, 121.8, 66.4, 60.1, 59.8 ppm. λmax (MeOH) 256, 295 nm. HRMS calculated for
C28H26N4O2Na+: 473.194797. Found:473.194444.
Symmetrical di-substituted 1,10-phenanthroline ligand
NN
NN
CHO
OHC
1,10-phenanthroline-2,9-dicarboxaldehyde (12). 20.0 g neocuproine hydrate (0.096
mol), 74.8 g SeO2 (0.67 mol), and 1400 mL 1,4 dioxane were refluxed for 1 hour. The
solution was filtered while hot and was concentrated under vacuum. The solid was
81
ground with a mortar and pestle and recrystallized from hot acetone and hexanes,
yielding 14.14 g pink powder (62.3 %). 1H NMR (300 MHz, DMSO-d6) δ 10.36 (d, 2H),
8.78 (d, 2H, J=8.23 Hz), 8.30 (d, 2H, J=8.26 Hz), 8.28 (s, 2H) ppm.11
NN
CHO
OHC NN
OEtO
OEt
O
1,10-phenanthroline ligand diethyl ester (13). 2.00 g (8.47 mmol) 1,10-
phenanthroline-2,9-dicarboxaldehyde was dissolved in 150 mL anhydrous DMF with
heat. 3.80 g (16.9 mmol) triethyl phosphonoacetate in 10 mL dry THF was added slowly
to a solution of 0.72 g NaH (60 % dispersion, 17.8 mmol) was dissolved in 20 mL
anhydrous THF. The anion was added slowly to the solution of substrate and the mixture
was stirred at room temperature for 4 hours. 100 mL saturated aqueous NH4Cl was
added to the opaque pale solution. The reaction mixture was diluted to 900 mL with H2O
and was chilled. A tan precipitate was filtered off. The aqueous solution was extracted
with CH2Cl2 and the organic solution was washed with H2O. The organic extract and
precipitate were combined and purified by a small basic alumina plug (eluent: 9:1
CH2Cl2:acetone). The diolefinated product was obtained by crystallization from hot
CH2Cl2 and hexanes, yielding 1.42 g (44.5 %). 1H-NMR (300 MHz, CDCl3) δ 8.29 (d,
2H, J=8.31 Hz), 8.15 (d, 2H, J=16.1 Hz), 7.90 (d, 2H, J=8.31 Hz), 7.82 (s, 2H), 7.11 (d,
2H, J=16.0 Hz), 4.34 (q, 4H, J=7.13 Hz), 1.39 (t, 6H, J=7.12 Hz) ppm. 13C-NMR (125
82
MHz, CDCl3) δ 166.5, 153.6, 146.0, 144.2, 136.9, 129.0, 127.0, 124.0, 122.1, 60.7, 14.2
ppm. MP=162-164 °C. HRMS calculated for C22H20N2O4Na+: 399.131528. Found:
399.132647.
Pyridine-phenanthroline hybrid ligands
N BrN NH2
2-bromo-6-methyl pyridine (14). 100 g 6-amino-2-picoline (2-amino-6-methyl pyridine,
0.92 mol) was added in portions to a stirring solution of 500 mL HBr (48 %, 4.42 mol).
The reaction mixture was cooled to -20 °C at which point 133 mL Br2 (2.59 mol) was
added dropwise and the solution was stirred for 1 hour. A solution of 170 g NaNO2 (2.46
mol) in 250 mL H2O was added slowly and the solution was warmed to -10 °C. The
reaction was cooled to -20 °C. A solution of 667 g NaOH (16.7 mol) in 1 L H2O was
added slowly while keeping the reaction temperature less than -10 °C. The reaction
mixture was then warmed to room temperature and extracted with ethyl acetate, followed
by a wash with brine. After drying over anhydrous sodium sulfate, the solution was
concentrated and the product was obtained by vacuum fractional distillation (lit. B.P.
198-201 °C), yielding 100.30 g (63.4 % yield) pale yellow oil. 1H NMR (300
MHz,CDCl3) δ 7.43 (t, 1H, J=7.7 Hz), 7.28 (d, 1H, J=7.3 Hz), 7.10 (d, 1H, J=7.5 Hz),
2.54 (s, 3H) ppm.7
83
NN
NNN
2-(2’-pyridyl-6-methyl)-1,10-phenanthroline (15). 4.6 mL 2-bromo-6-methyl pyridine
(40.2 mmol) in 75 mL dry THF was chilled over dry ice and acetone to -78 °C at which
point 26.0 mL n-BuLi (1.6 M in hexanes, 41.6 mmol) was added dropwise. After stirring
15 minutes, the red lithiate was cannulated into a 0 °C solution of 5.00 g 1,10-
phenanthroline (27.7 mmol) in 75 mL dry THF. The dark solution was allowed to stir for
3 hours at which point 400 mL bleach, 100 mL NaHCO3 solution, and 150 mL THF were
added. The biphasic solution was stirred vigorously overnight. The dark organic
solution was washed with 2 x 100 mL H2O, 200 mL brine, dried over MgSO4, and was
concentrated under vacuum. The product was purified by column chromatography (basic
alumina, 3 acetone : 7 hexanes). Evaporation of solvent gave 4.04 g light yellow crystals
(53.6 %). 1H-NMR (300 MHz, CDCl3) δ 9.25 (dd, 1H, J=1.8Hz, J=4.4Hz), 8.87 (d, 1H,
J=8.4Hz), 8.79 (d, 1H, J=7.8Hz), 8.36 (d, 1H, J=8.4Hz), 8.27 (dd, 1H, J=1.7Hz, J=8.1Hz),
7.81 (m, 3H), 7.65 (dd, 1H, J=4.4Hz, J=8.1Hz), 7.23 (d, 1H, J=7.6Hz), 2.69 (s, 3H) ppm.
13C-NMR (75 MHz, CDCl3) δ 157.3, 156.2, 155.1, 149.9, 146.0, 145.3, 136.7, 136.4,
135.7, 128.6, 128.3, 126.2, 126.1, 123.3, 122.4, 120.5, 119.4, 24.3 ppm. MP=164-166 °C.
Analysis calculated for C18H13N3: C 79.68, H 4.83, N 15.49. Found: C 79.87, H 4.95, N
15.30.
NNN
NNN
CHO
84
2-(2’-pyridyl-6-carboxaldehyde)-1,10-phenanthroline (16). 9.44 g (34.8 mmol) of
compound (15) was dissolved in 350 mL DMSO. 17.66 g I2 (69.6 mmol) was then added,
changing the solution from clear yellow to dark brown and the solution was allowed to
stir 5 minutes. 8.6 mL t-BuI (2-iodo-2-methylpropane, 72.0 mmol) was added followed
by a slow addition of 7.24 mL trifluoracetic acid (97.44 mmol). The solution was heated
to reflux for 66 hours. After cooling down, a solution of 63 g sodium thiosulfate
heptahydrate (0.28 mol) in 200 mL H2O was added slowly. The black precipitate was
filtered off and 400 mL saturated aqueous NaHCO3 was introduced carefully bringing the
pH to 9. The brown precipitate of product was filtered and re-dissolved in hot CHCl3.
The filtrate was extracted with CHCl3. The CHCl3 layers were combined, washed with 4
x 200 mL H2O, dried over MgSO4, and concentrated. 7.62 g light brown solid was
obtained (77 %). The aldehyde moves on silica gel with 20 % MeOH in acetone and 2 %
triethylamine. 1H-NMR (300 MHz, CDCl3) δ 10.25 (s, 1H), 9.28 (m, 2H), 8.98 (d, 1H,
J=8.40 Hz), 8.45 (d, 1H, J=8.41 Hz), 8.31 (dd, 1H, J=8.08 Hz, J=1.55 Hz), 8.09 (m, 2H),
7.89 (m, 2H), 7.69 (dd, 1H, J=4.3 Hz) ppm.8 13C-NMR (125 MHz, CDCl3) δ 193.6,
156.6, 154.9, 152.2, 150.4, 146.2, 145.7, 138.0, 137.2, 136.3, 129.1, 127.2, 126.8, 126.5,
123.1, 121.9, 120.8 ppm. MP=209-211 °C. HRMS calculated for C18H11N3ONa+:
308.079433. Found: 308.079996.
(EtO)2P CO2BnO
BrOBn
O
Benzyl diethylphosphonoacetate (17). 12.0 mL benzyl-2 bromoacetate (75.7 mmol)
and 100 mL triethyl phosphite (58.3 mmol) were combined in a 1 L round bottom flask
and the headspace was purged with Ar. The flask was stoppered and the mixture was
85
heated to 110 °C overnight. The product was purified by vacuum fractional distillation,
yielding 22.8 g product. 1H NMR (300 MHz, CDCl3) δ ppm 7.37 (m, 5H), 5.18 (s, 2H),
4.13 (m, 4H), 3.03 (s, 1H), 3.00 (s, 1H), 1.30 (m, 6H) ppm.9
NNN
CHO
NNN
O OBn
Pyr-phen benzyl ester ligand (18). 2.00 g (7.01 mmol) of aldehyde (16) was dissolved
in 100 mL dry DMF. 1.90 g (6.64 mmol) benzyl diethylphosphonoacetate (17) was
dissolved in 20 mL dry DMF and was added dropwise into 0.32 g NaH (60 % in mineral
oil, 7.97 mmol) in 10 mL DMF. The anionic solution was stirred for 10 minutes and was
slowly dripped into the solution of aldehyde and the reaction was allowed to stir for 3
hours at room temperature. 100 mL saturated aqueous NH4Cl was added slowly at which
point the reaction was extracted with CH2Cl2. The organic solution was washed with
H2O and brine, dried over MgSO4, and concentrated under vacuum. The product was
chromatographed on silica gel (8:2 acetone:hexanes + 2 % TEA). The white powdery
product (1.70 g, 61 % yield) was obtained by recrystallization from hot CH2Cl2 and
hexanes. 1H-NMR (300 MHz, CDCl3) δ 9.25 (m, 1H), 9.03 (d, 1H, J=7.91 Hz), 8.95 (d,
1H, J=8.41 Hz), 8.40 (d, 1H, J=8.43 Hz), 8.29 (dd, 1H, J=8.05 Hz, 1.45 Hz), 7.89 (m,
4H), 7.69 (dd, 1H, J=8.08 Hz, 4.38Hz), 7.43 (m, 6H), 7.23 (d, 1H, J=15.5 Hz), 5.32 (s,
2H) ppm. 13C-NMR (125 MHz, CDCl3) δ 166.6, 156.1, 155.6, 151.7, 150.3, 146.2, 145.5,
86
143.9, 137.7, 136.9, 136.1, 135.9, 128.9, 128.5, 128.2, 126.8, 126.5, 124.8, 123.3, 122.9,
121.9, 120.9, 66.5 ppm. λmax (MeOH) 326, 366 nm. MP=143-144 °C. HRMS
calculated for C27H19N3O2Na+: 440.136948. Found: 440.137390.
NNN
CHO
NNN
O OEt
Pyr-phen ethyl ester ligand (19). 5.0 g (17.5 mmol) of aldehyde (16) was dissolved in
150 mL anhydrous DMF and 100 mL dry THF. 0.73 g (18.2 mmol) NaH (60 %
dispersion in mineral oil) was dissolved in 50 mL dry THF and was added slowly to a
solution of 3.19 mL triethyl phosphonoacetate (15.9 mmol) dissolved in 50 mL dry THF.
The anionic solution was added dropwise to the stirring solution of aldehyde and the
reaction was allowed to stir for 3 hours at room temperature. 200 mL saturated aqueous
NH4Cl solution was added, bringing the pH to 9.5. 200 mL H2O and 200 mL CH2Cl2
were added and the solution was phase separated. The aqueous layer was extracted with
3 x 200 mL CH2Cl2. The organics were washed with 3 x 200 mL H2O and 2 x 200 mL
brine. The material was then dried over anhydrous MgSO4 and concentrated under
vacuum. The crude material was chromatographed on silica gel (8:2 acetone:hexanes, 2
% triethylamine), followed by crystallization of the product-containing fractions, yielding
3.54 g tan solid (57 %). 1H-NMR (300 MHz, CDCl3) δ 9.25 (d, 1H, J=4.23 Hz), 9.03 (d,
1H, J=9.24 Hz), 8.93 (d, 1H, J=8.39 Hz), 8.37 (d, 1H, J=8.41 Hz), 8.27 (d, 1H, J=8.02
87
Hz), 7.94 (t, 1H, J=7.7 Hz), 7.81 (m, 3H), 7.66 (dd, 1H, J=7.98 Hz, J=4.36 Hz), 7.48 (d,
1H, J=7.58 Hz), 7.16 (d, 1H, J=15.6 Hz), 4.33 (q, 2H, J=7.11 Hz), 1.38 (t, 3H, J=7.13 Hz)
ppm. MP=163-166 °C. 13C-NMR (125 MHz, CDCl3) δ 166.7, 156.0, 155.5, 151.8, 150.3,
146.1, 145.4, 143.2, 137.6, 136.8, 136.1, 128.8, 126.8, 126.4, 124.6, 123.2, 122.8, 122.2,
120.8, 60.6, 14.2 ppm. HRMS calculated for C22H17N3O2Na+: 378.121298. Found:
378.122124.
General procedure for prep scale photolysis with benzyl ester ligand. To a stirring
aqueous solution of CuSO4·5H2O (69 mg, 0.275 mmol) in 180 mL H2O was added a
methanolic solution of compound (18) (100 mg, 0.239 mmol in 20 mL). The solution
was degassed by bubbling Ar through a needle for 1.5 hours. The clear green solution
was stirred and irradiated with >350 nm high intensity light for a given time. The
solution was stirred in the dark for several days at which point it was extracted 5-10 times
with 50 mL diethyl ether. The extracts were combined, washed with 50 mL brine, and
dried over anhydrous MgSO4. The ether layer was partially concentrated under vacuum
at 25-30 °C at which point it was dried again, using anhydrous diethyl ether to rinse the
flask. The material was concentrated under vacuum partially and was allowed to
evaporate to dryness with a gentle stream of air, giving a mass of isolated benzyl alcohol.
0.22 g (2.5 equivalents) of EDTA disodium salt was added to the aqueous solution and it
was stirred overnight. The pH was adjusted from 5.5 to 9 with an aqueous saturated
NaHCO3 solution, resulting in an opaque blue solution. The solution was extracted with
7 x 50 mL CH2Cl2 which was then washed with brine, dried over anhydrous MgSO4, and
88
concentrated under vacuum, yielding a measured mass of free ligand material. The
material was analyzed by 1HNMR and in some cases separated by preparative TLC
(silica gel, 9:1 acetone:MeOH, +2 % TEA).
NNN
O OEt
NNN
O OLi
Pyr-phen Li carboxylate (20). 3.22 g of compound (19) (9.06 mmol) and 0.38 g LiOH
monohydrate (9.06 mmol) were dissolved in 50 mL THF and 30 mL H2O and the
solution was stirred at room temperature for 4 days. The solution was concentrated under
vacuum, yielding 3.00 g tan solid (99 %). 1H-NMR (300 MHz, DMSO-d6) δ 9.18 (dd,
1H, J=4.27 Hz, J=1.55 Hz), 8.86 (d, 1H, J=8.39 Hz), 8.72 (d, 1H, J=7.73 Hz), 8.64 (d, 1H,
J=8.41 Hz), 8.52 (d, 1H, J=8.03 Hz), 8.03 (m, 3H), 7.81 (dd, 1H, J=4.26 Hz, 3.76 Hz),
7.65 (d, 1H, J=7.50 Hz), 7.30 (d, 1H, J=15.69 Hz), 6.98 (d, 1H, J=15.69 Hz) ppm. 13C-
NMR (125 MHz, DMSO-d6) δ 169.7, 155.3, 155.2, 150.3, 145.7, 145.2, 138.2, 137.6,
136.6, 135.2, 135.1, 129.0, 128.8, 127.3, 126.7, 123.7, 123.2, 120.5, 120.2 ppm.
MP>210 °C. HRMS calculated for C20H12LiN3O2Na+: 356.098177. Found: 356.098596.
89
NNN
O O
NNN
O OLi
Pyr-phen phenethyl ligand (21). A solution of 0.50 g (1.5 mmol) of compound (20),
194 µL (2-bromoethyl)benzene (1.42 mmol), 0.24 g CsF (1.5 mmol), and 20 mL
anhydrous DMF was heated to 60 °C for 24 hours. 100 mL saturated aqueous NaHCO3
and 50 mL CH2Cl2 were added. The aqueous layer was extracted with CH2Cl2 and the
organics were washed with 2 x100 mL NaHCO3 solution and 3 x 100 mL brine. After
drying over MgSO4, the solution was concentrated under vacuum, yielding 0.50 g of a
white solid (82 % yield). 1H-NMR (300 MHz, CDCl3) δ 9.26 (d, 1H, J=4.30 Hz), 9.03 (d,
1H, J=7.95 Hz), 8.96 (d, 1H, J=8.36 Hz), 8.41 (d, 1H, J=8.40 Hz), 8.29 (d, 1H, J=8.04
Hz), 7.94 (t, 1H, J=15.50 Hz), 7.86 (q, 2H, J=21.44 Hz, J=8.73 Hz), 7.79 (d, 1H, J=15.57
Hz), 7.67 (q, 1H, J=7.98 Hz, J=4.40 Hz), 7.49 (d, 1H, J=7.54 Hz), 7.30 (m, 5H), 7.16 (d,
1H, J=15.6 Hz), 4.49 (t, 2H, J=7.13 Hz), 3.07 (t, 2H, 7.08 Hz). 13C-NMR (125 MHz,
CDCl3) δ 166.7, 156.2, 155.7, 151.9, 150.4, 146.3, 145.6, 143.6, 137.8, 137.7, 136.9,
136.2, 129.0, 129.0, 128.9, 128.5, 126.9, 126.6, 126.5, 124.8, 123.3, 122.9, 122.1, 120.9,
65.1, 35.2. MP=207-209 °C. HRMS calculated for C28H21N3O2Na+: 454.152598. Found:
454.152200.
90
NNN
O O
NNN
O OLi
OMe
Pyr-phen 4-methoxy benzyl ester ligand (22). A solution of 1.00 g (3.0 mmol) of
compound (20), 40 mL anhydrous DMF, 0.46 g CsF (3.0 mmol), and 386 µL 4-methoxy
benzyl chloride was heated to 60 °C for 18 hours. 100 mL saturated aqueous NaHCO3
and 100 mL CH2Cl2 was added. The aqueous layer was extracted with 2 x 50 mL CH2Cl2
and the organics were washed with 2 x100 mL NaHCO3 solution, 2 x 100 mL H2O, and 2
x 100 mL brine. After drying over MgSO4, the solution was concentrated under vacuum
and recrystallized from hot CHCl3 and hexanes, yielding 0.40 g light tan solid (30 %
yield). Alternatively, an 80 % yield was achieved by chromatographing the concentrated
reaction solution (4:1 acetone:hexanes, silica gel + 2 % TEA). 1H-NMR (300 MHz,
CDCl3) δ 10.13 (d, 1H, J=7.98 Hz), 9.82 (dd, 1H, J=5.51 Hz, J=1.31 Hz), 9.19 (d, 1H,
J=8.59 Hz), 8.94 (dd, 1H, J=8.24 Hz, J=1.24 Hz), 8.51 (d, 1H, J=8.59 Hz), 8.16 (m, 3H),
8.01 (d, 1H, J=8.92 Hz), 7.81 (d, 1H, J=15.62 Hz), 7.54 (d, 1H, J=7.34 Hz), 7.41 (d, 2H,
J=8.59 Hz), 7.16 (d, 1H, J=15.60 Hz), 6.95 (d, 2H, J=8.64 Hz), 5.25 (s, 2H), 3.84 (s, 3H).
13C-NMR (125 MHz, CDCl3) δ 166.6, 159.7, 157.6, 154.0, 151.5, 144.8, 144.5, 143.6,
139.0, 138.6, 137.1, 130.2, 130.0, 129.8, 129.6, 128.0, 125.8, 125.7, 124.3, 123.8, 123.6,
122.1, 114.0, 66.4, 55.3. MP=151-154 °C. HRMS calculated for C28H21N3O3Na+:
470.147513. Found: 470.147399.
91
Br
O
OH Br
O
OEt
Ethyl 5-bromovalerate (23). A solution of 5.00 g 5-bromovaleric acid (27.6 mmol), 5
drops concentrated H2SO4, and 100 mL EtOH was refluxed for 4 hours. The EtOH was
removed under vacuum and the material was redissolved in 100 mL CH2Cl2. 100 mL
saturated aqueous NaHCO3 solution was added. The aqueous layer was extracted with 2
x 50 mL CH2Cl2 and the organics were washed with 2 x 100 mL bicarbonate solution.
The material was dried over MgSO4 and concentrated to 4.96 g light yellow oil (86 %).
1H-NMR (300 MHz, CDCl3) δ 4.14 (q, 2H, J=7.14 Hz), 3.42 (t, 2H, J=6.62 Hz), 2.34 (t,
2H), 1.85 (m, 4H), 1.26 (t, 3H, J=7.13 Hz)10.
NNN
O O
NNN
O OLi
O
O
Pyr-phen ethyl valerate ligand (24). A solution of 1.00 g (3.0 mmol) of compound (20),
0.58 g ethyl 5-bromovalerate (2.77 mmol), 0.46 g CsF (3.0 mmol), and 40 mL anhydrous
DMF was heated to 60 °C for 20 hours. 100 mL saturated aqueous NaHCO3 and 50 mL
CH2Cl2 were added. The aqueous layer was extracted with CH2Cl2 and the organics were
washed with 2 x100 mL NaHCO3 solution, 3 x 100 mL H2O, and 2 x 100 mL brine.
After drying over MgSO4, the solution was concentrated under vacuum, yielding 1.06 g
tan solid (84 %). 1H-NMR (300 MHz, CDCl3) δ 9.25 (dd, 1H, J=4.29 Hz, J=1.51 Hz),
9.03 (d, 1H, J=7.92 Hz), 8.96 (d, 1H, J=8.42 Hz), 8.40 (d, 1H, J=8.40 Hz), 8.28 (dd, 1H,
92
J=8.06 Hz, J=1.54 Hz), 7.87 (m, 4H), 7.66 (dd, 1H, J=8.07 Hz, J=4.34 Hz), 7.49 (d, 1H,
J=7.58 Hz), 7.17 (d, 1H, J=15.60 Hz), 4.29 (t, 2H, J=5.74 Hz), 4.16 (q, 2H, J=7.13 Hz),
2.41 (m, 2H), 1.81 (m, 4H), 1.27 (t, 3H). MP=103-105 °C. 13C-NMR (125 MHz, CDCl3)
δ 173.3, 166.9, 156.2, 155.8, 151.9, 150.5, 146.4, 145.7, 143.6, 137.8, 137.0, 136.2, 129.1,
129.0, 126.9, 126.6, 124.8, 123.4, 123.0, 122.2, 121.0, 64.2, 60.4, 33.9, 28.2, 21.6, 14.3
ppm. HRMS calculated for C27H25N3O4Na+: 478.173727. Found: 478.173429.
PO
OO
PO
OO
O
OH
O
O
L-(-) menthyl diethylphosphonoacetate (25). A solution of 2.00 g
diethylphosphonoacetic acid (10.2 mmol), 1.27 g L-(-) menthol (8.15 mmol), 0.25 g
DMAP (2.04 mmol), and 100 mL dry CH2Cl2 was chilled under Ar to 0 °C. 1.89 g DCC
was then added and the solution was stirred overnight. The white precipitate
(dicyclohexylurea) was vacuum-filtered off (twice) and the organic solution was washed
with 5 x 75 mL saturated sodium bicarbonate solution. The solution was dried over
anhydrous MgSO4 and was concentrated to an opaque oil (1.24 g, 46 %). 1H-NMR (300
MHz, CDCl3) δ 4.73 (td, 1H, J=10.90 Hz, J=4.39 Hz), 4.17 (quint, 4H, J=7.13 Hz), 2.95
(d, 2H, J=21.68 Hz), 1.98 (m, 2H), 1.67 (m, 2H), 1.46 (m, 1H), 1.35 (t, 6H, J=7.07 Hz),
1.26 (m, 1H), 1.03 (m, 2H, J=48.75 Hz), 0.90 (dd, 6H, J=7.05 Hz, J=2.42 Hz), 0.83 (m,
1H), 0.76 (d, 3H, J=6.94 Hz). 13C-NMR (125 MHz, CDCl3) δ 165.2, 75.5, 62.4, 62.3,
46.7, 40.5, 35.0, 34.0, 33.9, 31.2, 25.6, 23.0, 21.8, 20.7, 16.2, 16.1, 16.0. HRMS
calculated for C16H31O5PNa+: 357.180132. Found: 357.180063.
93
NNN
CHO
NNN
O O
Pyr-phen L-(-) menthyl ester ligand (26). 0.98 g (3.43 mmol) of aldehyde (16) was
dissolved in 50 mL anhydrous DMF. 1.10 g (3.29 mmol) of compound (25) was
dissolved in 12 mL DMF and was added dropwise to a suspension of 0.15 g NaH (60 %
in mineral oil, 3.78 mmol) in 13 mL DMF. The anionic solution was stirred for 10
minutes at which point it was added dropwise to the stirring solution of aldehyde. The
reaction stirred at room temperature for 3 hours at which point 50 mL saturated aqueous
NaHCO3 solution, 200 mL H2O, and 100 mL CH2Cl2 were added. The aqueous layer
was extracted with 2 x 50 mL CH2Cl2 and then the organics were washed with 2 x 100
mL H2O and 2 x 100 mL brine solution. The organic solution was dried over MgSO4 and
concentrated under vacuum. The product was chromatographed on silica gel (1:1
acetone:hexanes + 2 % TEA) and recrystallized from hot acetone and water, yielding
0.68 g tan solid (44 % yield). 1H-NMR (300 MHz, CDCl3) δ 9.26 (dd, 1H, J=4.37 Hz,
J=1.70 Hz), 9.02 (dd, 1H, J=8.00 Hz, J=0.75 Hz), 8.97 (d, 1H, J=8.40 Hz), 8.41 (d, 1H,
J=8.43 Hz), 8.29 (dd, 1H, J=8.05 Hz, J=1.71 Hz), 7.91 (m, 3H), 7.79 (d, 1H, J=15.50 Hz),
7.67 (dd, 1H, J=8.05 Hz, J=4.38 Hz), 7.50 (d, 1H, J=7.63 Hz), 7.16 (d, 1H, J=15.60 Hz),
4.89 (td, 1H, J=10.86 Hz, J=4.37 Hz), 2.11 (m, 1H), 2.05 (m, 1H), 1.74 (m, 2H), 1.51 (m,
2H), 1.13 (m, 2H), 0.94 (d, 7H, J=8.04 Hz), 0.82 (d, 3H, J=6.94 Hz). 13C-NMR (125
MHz, CDCl3) δ 166.5, 156.2, 155.8, 152.1, 150.5, 146.4, 145.7, 143.2, 137.8, 137.0,
136.2, 129.1, 129.0, 126.9, 126.6, 124.8, 123.3, 123.0, 122.8, 121.0, 74.5, 47.3, 41.0, 34.3,
94
31.5, 26.3, 23.5, 22.1, 20.8, 16.3. MP=138-140 °C. HRMS calculated for
C30H31N3O2Na+: 488.230848. Found: 488.229555.
UV-vis binding titration procedure. To a solution of 24 µM CuSO4 in MeOH was
added a solution of 96 µM ligand in MeOH. 30 µL aliquots were added stepwise and a
UV-vis spectrum was taken for each addition. Once the ligand to metal ratio had
exceeded 2, the aliquot volume was increased to 60 µL. Titrations were continued out to
a metal to ligand ratio greater than or equal to 3. Absorbance at 368 nm was noted for
each concentration and was corrected for change in volume by using Beer’s Law. Delta
absorbance was calculated by adjusting the 368 nm absorbance of the various aliquots
relative to the initial metal solution’s value of zero. Two trend lines were created from
the generated curve of wavelength vs. delta absorbance. The X-axis value for the
intersection of the two trend lines gave the ligand to metal stoichiometry.
PO
OO
PO
OO
O
OHO
NH
Diethylphosphonoacetic benzyl amide (27). A solution of 100 mL anhydrous CH2Cl2,
5.0 g diethyl phosphonoacetic acid (25.5 mmol), 0.62 g DMAP (5.1 mmol), and 3.1 mL
benzylamine (28 mmol) was chilled over ice water to 0° C for 30 minutes. 5.78 g DCC
(28 mmol) was added quickly and the reaction stirred overnight. The reaction became
cloudy after two hours and was very white the next morning. The white solid was
removed by vacuum filtration (twice) and the organic solution was washed with 3 x 50
95
mL saturated aqueous NaHCO3 solution and 2 x 100 mL brine. The organic solution was
dried over MgSO4 and concentrated under vacuum, yielding 7.08 g low-melting white
solid (97 % yield). MP=58-61 °C. 1H-NMR (300 MHz, CDCl3) δ 7.30 (m, 5H), 7.07 (s,
1H), 4.47 (d, 1H, 5.82), 4.10 (m, 4H), 2.88 (d, 2H, J=20.48 Hz), 1.31 (t, 6H, J=7.08 Hz).
13C-NMR (125 MHz, CDCl3) δ 163.8, 137.9, 128.2, 127.3, 127.0, 62.4, 62.3, 55.4, 43.4,
35.4, 34.6, 34.3, 25.2, 24.4, 16.0. HRMS calculated for C13H20NO4PNa+: 308.102216.
Found: 308.102578.
N
96
on silica gel (9:1 acetone:hexanes + 2 % TEA) and was recrystallized from hot
chloroform and hexanes, yielding 1.46 g cream-colored solid (52 % yield). 1H-NMR
(300 MHz, CDCl3) δ 9.24 (dd, 1H, J=4.25 Hz, J=1.57 Hz), 8.96 (d, 1H, J=7.95 Hz), 8.87
(d, 1H, J=8.39 Hz), 8.35 (d, 1H, J=8.41 Hz), 8.28 (dd, 1H, J=7.98 Hz, J=1.59 Hz), 7.89
(m, 3H), 7.77 (d, 1H, J=15.12 Hz), 7.67 (dd, 1H, J=7.97 Hz, J=4.31 Hz), 7.30 (m, 6H),
7.23 (d, 1H, buried under solvent), 6.20 (t, 1H, J=4.76 Hz), 4.64 (d, 2H, J=5.75 Hz). 13C-
NMR (125 MHz, CDCl3) δ 165.6, 156.1, 155.9, 152.2, 150.5, 146.4, 145.7, 140.1, 138.1,
137.8, 136.9, 136.2, 129.1, 128.9, 128.8, 128.0, 127.6, 126.9, 126.5, 125.0, 124.5, 123.1,
123.0, 120.9, 44.0. MP=223-224 °C. HRMS calculated for C27H20N4ONa+: 439.152932.
Found: 439.152156.
97
REFERENCES
1. Taylor, C. M.; Watton, S.P.; Flurie, A.; Ricketts, J.I. “Speciation of Ternary Cobalt(II) Phenanthroline-Silica Surface Complexes as a Function of pH and Ligand Steric Bulk,” Inorg. Chem. 2003, 42, 7381-7386.
2. Dong, L.C., “The synthesis, characterization and investigation of
phenanthrolinylporphyrins,” Ph.D. Dissertation, Princeton University: 1991.
3. Zhang, T., Anslyn, E.V., “Molecular recognition and indicator-displacement assays for phosphoesters,” Tetrahedron. 2004, 60, 11117-11124.
4. Hicks, R. G., Koivisto, B. D., Lemaire, M. T., “Synthesis of Multitopic Verdazyl
Radical Ligands. Paramagnetic Supramolecular Synthons,” Org. Lett. 2004, 6, 1887-90.
5. Lucchese, B., Humphreys, K. J., Lee, D.-H., Incarvito, C. D., Sommer, R. D.,
Rheingold, A. L., Karlin, K. D., “Mono-, Bi- and Trinuclear Cu(II)-Cl Containing Products Based on the Tris(2-pyridylmethyl)amine Chelate Derived from Copper(I) Complex Dechlorination Reactions of Chloroform,” Inorg. Chem. 2004, 43, 5987-5998.
6. He, Z., Chaimungkalanont, P.J., Craig, D.C., Colbran, S.B., “Copper(II)
complexes of 6-hydroxymethyl-substituted tris(2-pyridylmethyl)amine ligands,” Dalton Trans. 2000, 9, 1419-1429.
7. Schubert, U. S.; Eschbaumer, C.; Heller, M. “Stille-Type Cross Coupling-An
Efficient Way to Various Symmetrically and Unsymmetrically Substituted Methyl-Bipyridines: Toward New ATRP Catalysts,” Org. Lett. 2000, 2, 3373-3376.
8. Angeloff, A.; Daran, J-C.; Bernadou, J.; Meunier, B., “The Ligand 1,10-
Phenanthroline-2,9-dicarbaldehyde Dioxime can Act Both as a Tridentate and as a Tetradentate Ligand 2 Synthesis, Characterization and Crystal Structures of its Transition Metal Complexes,” Eur. J. Inorg. Chem. 2000, 1985-1996.
9. O'Leary, B. M., Szabo, T., Svenstrup, N., Schalley, C. A., Lutzen, A., Schafer, M.,
Rebek, J., Jr., “’Flexiball’ Toolkit: A Modular Approach to Self-Assembling Capsules,” J. Am. Chem. Soc. 2001, 123, 11519-11533.
10. Saito, T., Hayamizu, K., Yanagisawa, M., Yamamoto, O., “ethyl 5-
bromovalerate,” SDBSWeb : http://www.aist.go.jp/RIODB/SDBS/. National Institute of Advanced Industrial Science and Technology. July 2006.
11. Chandler, C. J., Deady, L.W., Reiss, J.A., “Synthesis of some 2,9-disubstituted-
1,10-phenanthrolines,” J. Het. Chem. 1980, 18, 599-601.
98
APPENDIX A
X-ray crystallographic data
99
Compound (4)
Ligand (4) thermal ellipsoid structure.
Single crystals of C22H16N2O2 are, at 293(2)oK, monoclinic, space group P2(1)/c -
C 52h (No. 14) with a = 10.311(7) Å, b = = 22.708(15) Å, c = 8.068(5) Å, ß = 112.741(9)°,
V = 1742(2) Å3, and Z = 4 formula units {dcalcd = 1.298 gcm-3; µa(MoKα ) = 0.0847mm-1}.
A pale yellow crystal of approximate dimensions 0.38 x 0.34 x 0.16 mm was used for the
X-ray crystallographic analysis. A full hemisphere of diffracted intensities (omega scan
width of 0.30°) was measured using graphite-monochromated MoKα radiation on a Bruker
100
SMART APEX CCD Single Crystal Diffraction System. X-rays were provided by a fine-
focus sealed x-ray tube operated at 50kV and 30mA.
Lattice constants were determined with the Bruker SMART software package
(SMART version 5.628 and SAINT version 6.36a., Bruker AXS Inc., Madison, Wisconsin,
USA.) using peak centers for 5208 reflections with 7.69°<2Θ<59.84°. A total of 17247
integrated intensities were produced using the Bruker program SAINT, of which 4757 were
independent and gave Rint = 0.050. Analysis of the data showed negligible decay during
data collection.
The structure was solved using "Direct Methods" techniques with the Bruker AXS
SHELXTL(vers 6.12) software package. All stages of weighted full-matrix least-squares
refinement were conducted using Fo2 data and converged to give R1 (unweighted, based on
F) = 0.0519 for 3164 independent reflections having 2Θ(MoKα ) < 58.7o and F2>2σ(F2);
{R1 (unweighted, based on F) = 0.0766 and wR2 (weighted, based on F2) = 0.1474 for all
4757 reflections}. The goodness-of-fit was 1.041. The largest peak in the final difference
Fourier map was 0.31 e-/Å3 and the largest hole was -0.16 e-/Å3.
The structural model incorporated anisotropic thermal parameters for all non-
hydrogen atoms and isotropic thermal parameters for all hydrogen atoms. The hydrogen
atoms were included in the structural model as fixed atoms (using idealized sp2- or sp3-
hybridized geometry and C-H bond lengths of 0.93-0.97 Å) "riding" on their respective
carbon atoms. The isotropic thermal parameter of each hydrogen atom was fixed at a value
1.2 times the equivalent isotropic thermal parameter of the carbon atom to which it is
covalently bonded.
101
All calculations were performed using the SHELXTL (Version 6.12) interactive
software package.
Crystal data and structure refinement for C22H16N2O2
Empirical formula C22 H16 N2 O2 Formula weight 340.37 Temperature 293(2) K Wavelength 0.71073 Å Crystal system Monoclinic Space group P2(1)/c - C 5
2h (No. 14)
Unit cell dimensions a = 10.311(7) Å b = 22.708(15) Å, β = 112.741(9)° c = 8.068(5) Å Volume 1742(2) Å3 Z 4 Density (calculated) 1.298 g/cm3 Absorption coefficient 0.084 mm-1 F(000) 712 Crystal size 0.38 x 0.34 x 0.16 mm3 Theta range for data collection 3.85 to 29.35° Index ranges -14≤h≤13, -31≤k≤31, -11≤l≤11 Reflections collected 17247 Independent reflections 4757 [R(int) = 0.0500] Completeness to theta = 29.35° 99.3 % Absorption correction None Refinement method Full-matrix least-squares on F2 Data / parameters 4757 / 235 Goodness-of-fit on F2 1.041 Final R indices [I>2σ(I)] R1 = 0.0519, wR2 = 0.1345 R indices (all data) R1 = 0.0766, wR2 = 0.1474 Largest diff. peak and hole 0.307 and -0.165 e-/Å3
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Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103) for C22H16N2O2. U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. ________________________________________________________________________ x y z U(eq) ________________________________________________________________________ O(1) 6035(1) 2150(1) -1385(1) 62(1) O(2) 8072(1) 1687(1) -820(1) 53(1) N(1) 6715(1) 888(1) 4113(1) 42(1) N(2) 8676(1) 56(1) 5968(2) 55(1) C(1) 6908(1) 1804(1) -518(2) 44(1) C(2) 6860(1) 1462(1) 1014(2) 45(1) C(3) 5928(1) 1591(1) 1710(2) 43(1) C(4) 5772(1) 1294(1) 3234(2) 42(1) C(5) 6570(1) 610(1) 5516(2) 43(1) C(6) 7603(1) 171(1) 6498(2) 47(1) C(7) 9597(2) -346(1) 6867(2) 66(1) C(8) 9529(2) -661(1) 8324(2) 78(1) C(9) 8461(2) -544(1) 8860(2) 73(1) C(10) 7461(2) -120(1) 7967(2) 56(1) C(11) 6304(2) 21(1) 8454(2) 66(1) C(12) 5344(2) 424(1) 7553(2) 63(1) C(13) 5446(1) 734(1) 6059(2) 50(1) C(14) 4479(1) 1163(1) 5098(2) 58(1) C(15) 4635(1) 1447(1) 3701(2) 55(1) C(16) 8247(1) 2021(1) -2258(2) 54(1) C(17) 9715(1) 1929(1) -2151(2) 46(1) C(18) 10023(1) 1487(1) -3115(2) 51(1) C(19) 11387(2) 1407(1) -2993(2) 58(1) C(20) 12439(2) 1769(1) -1937(2) 61(1) C(21) 12148(2) 2207(1) -967(2) 67(1) C(22) 10792(2) 2287(1) -1074(2) 62(1) ________________________________________________________________________
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Bond lengths [Å] and angles [°] for C22H16N2O2 ________________________________________________________________________O(1)-C(1) 1.1957(15) O(2)-C(1) 1.3403(15) O(2)-C(16) 1.4553(16) N(1)-C(4) 1.3292(16) N(1)-C(5) 1.3533(16) N(2)-C(7) 1.3149(18) N(2)-C(6) 1.3571(17) C(1)-C(2) 1.4763(18) C(2)-C(3) 1.3206(17) C(3)-C(4) 1.4650(17) C(4)-C(15) 1.4062(18) C(5)-C(13) 1.4171(18) C(5)-C(6) 1.4504(19) C(6)-C(10) 1.4132(18) C(7)-C(8) 1.401(2)
C(8)-C(9) 1.356(2) C(9)-C(10) 1.392(2) C(10)-C(11) 1.428(2) C(11)-C(12) 1.338(2) C(12)-C(13) 1.4343(19) C(13)-C(14) 1.395(2) C(14)-C(15) 1.362(2) C(16)-C(17) 1.497(2) C(17)-C(22) 1.3792(19) C(17)-C(18) 1.3796(18) C(18)-C(19) 1.385(2) C(19)-C(20) 1.366(2) C(20)-C(21) 1.368(2) C(21)-C(22) 1.378(2)
C(1)-O(2)-C(16) 115.93(9) C(4)-N(1)-C(5) 118.36(10) C(7)-N(2)-C(6) 117.59(12) O(1)-C(1)-O(2) 123.22(11) O(1)-C(1)-C(2) 125.09(11) O(2)-C(1)-C(2) 111.69(10) C(3)-C(2)-C(1) 120.26(11) C(2)-C(3)-C(4) 126.07(11) N(1)-C(4)-C(15) 122.83(11) N(1)-C(4)-C(3) 118.19(10) C(15)-C(4)-C(3) 118.99(11) N(1)-C(5)-C(13) 122.31(12) N(1)-C(5)-C(6) 118.82(11) C(13)-C(5)-C(6) 118.87(11) N(2)-C(6)-C(10) 122.40(12) N(2)-C(6)-C(5) 118.46(11) C(10)-C(6)-C(5) 119.14(12) N(2)-C(7)-C(8) 123.90(15)
C(9)-C(8)-C(7) 118.54(15) C(8)-C(9)-C(10) 120.10(14) C(9)-C(10)-C(6) 117.46(14) C(9)-C(10)-C(11) 122.87(13) C(6)-C(10)-C(11) 119.66(13) C(12)-C(11)-C(10) 121.64(13) C(11)-C(12)-C(13) 120.87(13) C(14)-C(13)-C(5) 117.44(12) C(14)-C(13)-C(12) 122.74(12) C(5)-C(13)-C(12) 119.82(13) C(15)-C(14)-C(13) 120.21(12) C(14)-C(15)-C(4) 118.85(13) O(2)-C(16)-C(17) 108.35(10) C(22)-C(17)-C(18) 118.58(12) C(22)-C(17)-C(16) 120.28(12) C(18)-C(17)-C(16) 121.13(12) C(17)-C(18)-C(19) 120.34(12) C(20)-C(19)-C(18) 120.29(13)
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C(19)-C(20)-C(21) 119.87(14) C(20)-C(21)-C(22) 120.06(13) C(21)-C(22)-C(17) 120.84(13)
Compound (13)
Thermal ellipsoid structure of (13).
Single crystals of C22H20N2O4 – H2O are, at 193(2)K, triclinic, space group P1 - C1
i
(No. 2) with a = 8.835(3) Å, b = 13.659(5) Å, c = 17.406(6) Å, α = 75.824(6)°, β =
76.028(6)°, γ = 84.624(6)°, V = 1975.0(12) Å3, and Z = 4 formula units {dcalcd = 1.326gcm-
3; µa(MoKα ) = 0.095mm-1}. A colorless crystal of approximate dimensions 0.19 x 0.16 x
0.04 mm3 was used for the X-ray crystallographic analysis. A full hemisphere of
diffracted intensities (omega scan width of 0.30°) was measured using graphite-
105
monochromated MoK α radiation on a Bruker SMART APEX CCD Single Crystal
Diffraction System. X-rays were provided by a fine-focus sealed x-ray tube operated at
50kV and 30mA.
Lattice constants were determined with the Bruker SMART software package
(SMART version 5.628 and SAINT version 6.36a., Bruker AXS Inc., Madison, Wisconsin,
USA.) using peak centers for 1146 reflections with 7.608° <2Θ< 41.548°. A total of 14486
integrated intensities were produced using the Bruker program SAINT, of which 6921 were
independent and gave Rint = 0.0674. Analysis of the data showed negligible decay during
data collection. Data were processed with Bruker area detector scaling and absorption
correction software using the multi-scan technique (SADABS).
The structure was solved using "Direct Methods" techniques with the Bruker AXS
SHELXTL (vers 6.12) software package. All stages of weighted full-matrix least-squares
refinement were conducted using Fo2 data and converged to give R1 (unweighted, based on
F) = 0.0825 for 4051 independent reflections having 2Θ(MoKα ) < 50.0o and F2>2σ(F2);
{R1 (unweighted, based on F) = 0.1439 and wR2 (weighted, based on F2) = 0.1914 for all
6921 reflections}. The goodness-of-fit was 1.047. The largest peak in the final difference
Fourier map was 0.308 e-/Å3 and the largest hole was -0.259 e-/Å3.
The structural model incorporated anisotropic thermal parameters for all
nonhydrogen atoms and isotropic thermal parameters for all hydrogen atoms. Hydrogen
atoms on the waters of crystallization were initially located from a difference Fourier
map. In subsequent refinement cycles, hydrogen atoms on O1 were refined using a DFIX
distance restraint with a target distance of 0.85 Å; hydrogen atoms on water oxygen O2
were refined independently. The remaining hydrogen atoms were included in the
106
structural model as fixed atoms (using idealized sp2- or sp3-hybridized geometry and C-H
bond lengths of 0.95 – 0.99 Å) "riding" on their respective carbon atoms. The isotropic
thermal parameter of each hydrogen atom was fixed at a value 1.2 (non-methyl) or
1.5(methyl) times the equivalent isotropic thermal parameter of the carbon atom to which it
is covalently bonded.
All calculations were performed using the SHELXTL (Version 6.12) interactive
software package (Bruker (2001)).
Crystal data and structure refinement for C22H20N2O4 – H2O Identification code a10k Empirical formula C22 H22 N2 O5 Formula weight 394.42 Temperature 193(2) K Wavelength 0.71073 Å Crystal system Triclinic Space group P1 - C1
i (No. 2)
Unit cell dimensions a = 8.835(3) Å, α = 75.824(6)° b = 13.659(5) Å, β = 76.028(6)° c = 17.406(6) Å, γ = 84.624(6)° Volume 1975.0(12) Å3 Z 4 Density (calculated) 1.326 g/cm3 Absorption coefficient 0.095 mm-1 F(000) 832 Crystal size 0.19 x 0.16 x 0.04 mm3 Theta range for data collection 3.80 to 25.00° Index ranges -10≤h≤10, -16≤k≤16, -20≤l≤20 Reflections collected 14486 Independent reflections 6921 [R(int) = 0.0674] Completeness to theta = 25.00° 99.4 %
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Absorption correction Multi-scan (SADABS) Max. and min. transmission 0.9962 and 0.9822 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 6921 / 2 / 539 Goodness-of-fit on F2 1.047 Final R indices [I>2sigma(I)] R1 = 0.0825, wR2 = 0.1651 R indices (all data) R1 = 0.1439, wR2 = 0.1914 Largest diff. peak and hole 0.308 and -0.259 e-/Å3 Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103) for C22H20N2O4 – H2O. U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. ________________________________________________________________________ x y z U(eq) ________________________________________________________________________ O(1A) 7662(4) 8749(2) -820(2) 49(1) O(2A) 9443(3) 9777(2) -1690(2) 37(1) O(3A) 691(4) 4046(2) 813(2) 51(1) O(4A) -703(3) 2888(2) 611(2) 44(1) N(1A) 4467(4) 4968(2) -1901(2) 29(1) N(2A) 6571(4) 6479(2) -2432(2) 27(1) C(1A) 5321(4) 5125(3) -2674(2) 29(1) C(2A) 6394(4) 5945(3) -2963(2) 28(1) C(3A) 7554(4) 7238(3) -2697(2) 25(1) C(4A) 8412(5) 7502(3) -3505(2) 31(1) C(5A) 8266(5) 6953(3) -4035(2) 35(1) C(6A) 7261(4) 6142(3) -3780(2) 29(1) C(7A) 7097(5) 5531(3) -4307(2) 39(1) C(8A) 6104(5) 4753(3) -4030(3) 41(1) C(9A) 5206(5) 4523(3) -3218(2) 33(1) C(10A) 4169(5) 3725(3) -2900(3) 39(1) C(11A) 3324(5) 3566(3) -2132(3) 40(1) C(12A) 3475(4) 4212(3) -1641(2) 30(1) C(13A) 7648(4) 7772(3) -2076(2) 30(1) C(14A) 8520(5) 8554(3) -2178(2) 31(1)
108
C(15A) 8475(5) 9009(3) -1496(2) 34(1) C(16A) 9483(6) 10247(3) -1034(3) 47(1) C(17A) 10606(6) 11093(4) -1375(3) 56(1) C(18A) 2539(5) 4125(3) -806(3) 36(1) C(19A) 1397(5) 3499(3) -425(3) 41(1) C(20A) 469(5) 3526(3) 391(3) 34(1) C(21A) -1798(5) 2882(3) 1382(2) 41(1) C(22A) -2889(5) 2043(3) 1512(3) 52(1) O(1) 5310(5) 5934(4) -617(2) 80(1) O(1B) -1007(3) -9412(2) -5646(2) 38(1) O(2B) -2481(3) -10761(2) -5402(2) 42(1) O(3B) 1971(3) -4265(2) -4259(2) 45(1) O(4B) 2358(3) -3351(2) -3425(2) 35(1) N(1B) -1714(4) -6835(2) -2503(2) 31(1) N(2B) -2758(4) -8382(2) -2951(2) 27(1) C(1B) -2790(4) -7437(3) -1947(2) 28(1) C(2B) -3353(4) -8263(3) -2185(2) 28(1) C(3B) -3258(4) -9137(3) -3172(2) 29(1) C(4B) -4378(5) -9810(3) -2643(2) 36(1) C(5B) -4977(5) -9687(3) -1873(2) 36(1) C(6B) -4478(4) -8899(3) -1613(2) 29(1) C(7B) -5073(5) -8714(3) -819(2) 39(1) C(8B) -4553(5) -7948(3) -603(2) 36(1) C(9B) -3388(5) -7300(3) -1150(2) 33(1) C(10B) -2787(5) -6516(3) -939(2) 39(1) C(11B) -1704(5) -5900(3) -1497(2) 38(1) C(12B) -1192(4) -6080(3) -2284(2) 29(1) C(13B) -2539(5) -9228(3) -4012(2) 31(1) C(14B) -2779(5) -9940(3) -4357(2) 37(1) C(15B) -1972(5) -9986(3) -5197(2) 31(1) C(16B) -1783(5) -10919(3) -6210(2) 48(1) C(17B) -2587(6) -11794(3) -6292(3) 52(1) C(18B) -71(5) -5446(3) -2925(2) 30(1) C(19B) 643(4) -4671(3) -2864(2) 30(1) C(20B) 1710(5) -4098(3) -3588(2) 33(1) C(21B) 3388(5) -2731(3) -4116(2) 38(1)
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C(22B) 4045(5) -1954(3) -3827(3) 48(1) O(2) -582(4) -6869(3) -4301(2) 57(1)
Bond lengths [Å] and angles [°] for C22H20N2O4 – H2O ________________________________________________________________________ O(1A)-C(15A) 1.208(4) O(2A)-C(15A) 1.342(4) O(2A)-C(16A) 1.448(4) O(3A)-C(20A) 1.197(4) O(4A)-C(20A) 1.339(4) O(4A)-C(21A) 1.451(5) N(1A)-C(12A) 1.337(5) N(1A)-C(1A) 1.351(5) N(2A)-C(3A) 1.335(4) N(2A)-C(2A) 1.353(4) C(1A)-C(9A) 1.423(5) C(1A)-C(2A) 1.449(5) C(2A)-C(6A) 1.417(5) C(3A)-C(4A) 1.403(5) C(3A)-C(13A) 1.466(5) C(4A)-C(5A) 1.358(5) C(5A)-C(6A) 1.403(5) C(6A)-C(7A) 1.421(5) C(7A)-C(8A) 1.361(6) C(8A)-C(9A) 1.419(6) C(9A)-C(10A) 1.406(5) C(10A)-C(11A) 1.341(6) C(11A)-C(12A) 1.406(5) C(12A)-C(18A) 1.470(6) C(13A)-C(14A) 1.328(5) C(14A)-C(15A) 1.460(5) C(16A)-C(17A) 1.506(6) C(18A)-C(19A) 1.323(5) C(19A)-C(20A) 1.465(6)
C(21A)-C(22A) 1.506(6) O(1)-H(1O1) 0.85(2) O(1)-H(1O2) 0.83(2) O(1B)-C(15B) 1.206(4) O(2B)-C(15B) 1.343(4) O(2B)-C(16B) 1.452(4) O(3B)-C(20B) 1.207(4) O(4B)-C(20B) 1.334(4) O(4B)-C(21B) 1.452(4) N(1B)-C(12B) 1.335(4) N(1B)-C(1B) 1.353(4) N(2B)-C(3B) 1.330(4) N(2B)-C(2B) 1.353(4) C(1B)-C(9B) 1.412(5) C(1B)-C(2B) 1.458(5) C(2B)-C(6B) 1.412(5) C(3B)-C(4B) 1.410(5) C(3B)-C(13B) 1.477(5) C(4B)-C(5B) 1.362(5) C(5B)-C(6B) 1.408(5) C(6B)-C(7B) 1.429(5) C(7B)-C(8B) 1.346(5) C(8B)-C(9B) 1.426(5) C(9B)-C(10B) 1.398(5) C(10B)-C(11B) 1.367(5) C(11B)-C(12B) 1.410(5) C(12B)-C(18B) 1.459(5) C(13B)-C(14B) 1.317(5) C(14B)-C(15B) 1.477(5)
110
C(16B)-C(17B) 1.498(6) C(18B)-C(19B) 1.320(5) C(19B)-C(20B) 1.473(5)
C(21B)-C(22B) 1.495(5) O(2)-H(2O1) 0.93(5) O(2)-H(2O2) 0.80(5)
C(15A)-O(2A)-C(16A) 115.8(3) C(20A)-O(4A)-C(21A) 117.3(3)
C(15B)-O(2B)-C(16B) 117.0(3) C(20B)-O(4B)-C(21B) 115.4(3)
C(12A)-N(1A)-C(1A) 118.1(3) C(3A)-N(2A)-C(2A) 118.8(3)
C(12B)-N(1B)-C(1B) 118.4(3) C(3B)-N(2B)-C(2B) 118.2(3)
N(1A)-C(1A)-C(9A) 122.9(3) N(1A)-C(1A)-C(2A) 118.5(3) C(9A)-C(1A)-C(2A) 118.6(3) N(2A)-C(2A)-C(6A) 122.0(3) N(2A)-C(2A)-C(1A) 118.6(3) C(6A)-C(2A)-C(1A) 119.3(3) N(2A)-C(3A)-C(4A) 122.5(3) N(2A)-C(3A)-C(13A) 114.3(3) C(4A)-C(3A)-C(13A) 123.2(3) C(5A)-C(4A)-C(3A) 119.0(4) C(4A)-C(5A)-C(6A) 120.4(4) C(5A)-C(6A)-C(2A) 117.2(3) C(5A)-C(6A)-C(7A) 122.5(4) C(2A)-C(6A)-C(7A) 120.3(4) C(8A)-C(7A)-C(6A) 120.2(4) C(7A)-C(8A)-C(9A) 121.9(4) C(10A)-C(9A)-C(8A) 124.1(4) C(10A)-C(9A)-C(1A) 116.2(4) C(8A)-C(9A)-C(1A) 119.7(4) C(11A)-C(10A)-C(9A) 121.1(4) C(10A)-C(11A)-C(12A) 119.2(4) N(1A)-C(12A)-C(11A) 122.5(4) N(1A)-C(12A)-C(18A) 114.6(3) C(11A)-C(12A)-C(18A) 122.9(4) C(14A)-C(13A)-C(3A) 126.6(3)
C(13A)-C(14A)-C(15A) 120.0(4) O(1A)-C(15A)-O(2A) 121.6(4) O(1A)-C(15A)-C(14A) 125.4(4) O(2A)-C(15A)-C(14A) 113.0(3) N(1B)-C(1B)-C(9B) 122.9(3) N(1B)-C(1B)-C(2B) 118.3(3) C(9B)-C(1B)-C(2B) 118.8(3) N(2B)-C(2B)-C(6B) 123.2(3) N(2B)-C(2B)-C(1B) 117.7(3) C(6B)-C(2B)-C(1B) 119.1(3) N(2B)-C(3B)-C(4B) 122.6(3) N(2B)-C(3B)-C(13B) 115.1(3) C(4B)-C(3B)-C(13B) 122.2(3) C(5B)-C(4B)-C(3B) 119.0(4) C(4B)-C(5B)-C(6B) 120.2(4) C(5B)-C(6B)-C(2B) 116.7(3) C(5B)-C(6B)-C(7B) 123.3(4) C(2B)-C(6B)-C(7B) 119.9(4) C(8B)-C(7B)-C(6B) 120.8(4) C(7B)-C(8B)-C(9B) 121.6(4) C(10B)-C(9B)-C(1B) 117.0(4) C(10B)-C(9B)-C(8B) 123.2(4) C(1B)-C(9B)-C(8B) 119.8(4) C(11B)-C(10B)-C(9B) 120.6(4) C(10B)-C(11B)-C(12B) 118.6(4)
111
N(1B)-C(12B)-C(11B) 122.6(4) N(1B)-C(12B)-C(18B) 115.0(3) C(11B)-C(12B)-C(18B) 122.4(3) C(14B)-C(13B)-C(3B) 126.6(4)
C(13B)-C(14B)-C(15B) 122.7(4) O(1B)-C(15B)-O(2B) 124.0(4) O(1B)-C(15B)-C(14B) 125.9(3) O(2B)-C(15B)-C(14B) 110.1(3)
O(2A)-C(16A)-C(17A) 107.7(3) O(4A)-C(21A)-C(22A) 106.2(3)
O(2B)-C(16B)-C(17B) 106.2(3) O(4B)-C(21B)-C(22B) 108.6(3)
C(19A)-C(18A)-C(12A) 127.0(4) C(18A)-C(19A)-C(20A) 122.3(4) O(3A)-C(20A)-O(4A) 123.4(4) O(3A)-C(20A)-C(19A) 125.9(4) O(4A)-C(20A)-C(19A) 110.8(3)
C(19B)-C(18B)-C(12B) 127.1(4) C(18B)-C(19B)-C(20B) 119.4(4) O(3B)-C(20B)-O(4B) 122.9(4) O(3B)-C(20B)-C(19B) 124.9(4) O(4B)-C(20B)-C(19B) 112.2(3)
H(1O1)-O(1)-H(1O2) 102(6) H(2O1)-O(2)-H(2O2) 103(5)
112
Compound (15)
Top: Thermal ellipsoid structure of (15). Bottom: photograph of large crystals of (15).
113
Packing structure of crystals of (15).
114
Single crystals of C18H13N3 are, at 193(2)K, monoclinic, space group P21/c - C 52h
(No. 14) with a = 21.015(2) Å, b = 13.302(1) Å, c = 14.826(1) Å, β = 97.728(1)°, V =
4106.7(6) Å3, and Z = 12 formula units {dcalcd = 1.316gcm-3; µa(MoKα ) = 0.080mm-1}. A
colorless crystal of approximate dimensions 0.50 x 0.32 x 0.18 mm3 was used for the X-
ray crystallographic analysis. A full hemisphere of diffracted intensities (omega scan width
of 0.30°) was measured using graphite-monochromated MoKα radiation on a Bruker
SMART APEX CCD Single Crystal Diffraction System. X-rays were provided by a fine-
focus sealed x-ray tube operated at 50kV and 30mA.
Lattice constants were determined with the Bruker SMART software package
(SMART version 5.628 and SAINT version 6.36a., Bruker AXS Inc., Madison, Wisconsin,
USA.) using peak centers for 9397 reflections with 7.592° <2Θ< 59.900°. A total of 34417
integrated intensities were produced using the Bruker program SAINT, of which 9376 were
independent and gave Rint = 0.0603. Analysis of the data showed negligible decay during
data collection. Data were processed with Bruker area detector scaling and absorption
correction software using the multi-scan technique (SADABS).
The structure was solved using "Direct Methods" techniques with the Bruker AXS
SHELXTL (vers 6.12) software package. All stages of weighted full-matrix least-squares
refinement were conducted using Fo2 data and converged to give R1 (unweighted, based on
F) = 0.0579 for 7320 independent reflections having 2Θ(MoKα ) < 55.0o and F2>2σ(F2);
{R1 (unweighted, based on F) = 0.0712 and wR2 (weighted, based on F2) = 0.1665 for all
9376 reflections}. The goodness-of-fit was 1.025. The largest peak in the final difference
Fourier map was 0.444 e-/Å3 and the largest hole was -0.227 e-/Å3.
115
The structural model incorporated anisotropic thermal parameters for all
nonhydrogen atoms and isotropic thermal parameters for all hydrogen atoms. All hydrogen
atoms were included in the structural model as fixed atoms (using idealized sp2- or sp3-
hybridized geometry and C-H bond lengths of 0.95 – 0.98 Å) "riding" on their respective
carbon atoms. The isotropic thermal parameter of each hydrogen atom was fixed at a value
1.2 (non-methyl) or 1.5(methyl) times the equivalent isotropic thermal parameter of the
carbon atom to which it is covalently bonded.
All calculations were performed using the SHELXTL (Version 6.12) interactive
software package (Bruker (2001)).
Crystal data and structure refinement for C18H13N3 Identification code a07j Empirical formula C18 H13 N3 Formula weight 271.31 Temperature 193(2) K Wavelength 0.71073 Å Crystal system Monoclinic Space group P2(1)/c -C 5
2h (No. 14)
Unit cell dimensions a = 21.0152(17) Å b = 13.3016(11) Å, β = 97.728(1)° c = 14.8257(12) Å Volume 4106.7(6) Å3 Z 12 Density (calculated) 1.316 g/cm3 Absorption coefficient 0.080 mm-1 F(000) 1704 Crystal size 0.50 x 0.32 x 0.18 mm3 Theta range for data collection 3.80 to 27.50° Index ranges -27≤h≤27, -17≤k≤17, -19≤l≤19
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Reflections collected 34417 Independent reflections 9376 [R(int) = 0.0603] Completeness to theta = 27.50° 99.3 % Absorption correction Multi-scan (SADABS) Refinement method Full-matrix least-squares on F2 Data / parameters 9376 / 571 Goodness-of-fit on F2 1.025 Final R indices [I>2sigma(I)] R1 = 0.0579, wR2 = 0.1534 R indices (all data) R1 = 0.0712, wR2 = 0.1665 Largest diff. peak and hole 0.444 and -0.227 e-/Å3 Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103) for C18H13N3. U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. ________________________________________________________________________ x y z U(eq) ________________________________________________________________________
Molecule A N(1A) -825(1) 7292(1) 5316(1) 36(1) N(2A) 142(1) 6134(1) 3783(1) 29(1) N(3A) 1071(1) 5954(1) 2632(1) 36(1) C(1A) -318(1) 7161(1) 4864(1) 31(1) C(2A) 180(1) 7854(1) 4891(1) 35(1) C(3A) 147(1) 8719(1) 5404(1) 42(1) C(4A) -371(1) 8850(1) 5874(1) 43(1) C(5A) -846(1) 8121(1) 5823(1) 40(1) C(6A) -1409(1) 8221(1) 6343(1) 56(1) C(7A) -313(1) 6218(1) 4323(1) 30(1) C(8A) 171(1) 5275(1) 3301(1) 29(1) C(9A) -265(1) 4471(1) 3352(1) 31(1) C(10A) -744(1) 4598(1) 3917(1) 37(1) C(11A) -771(1) 5462(1) 4406(1) 36(1) C(12A) 665(1) 5171(1) 2707(1) 30(1) C(13A) 700(1) 4263(1) 2219(1) 32(1) C(14A) 259(1) 3463(1) 2319(1) 37(1)
117
C(15A) -205(1) 3563(1) 2856(1) 36(1) C(16A) 1504(1) 5842(1) 2064(1) 39(1) C(17A) 1568(1) 4978(1) 1542(1) 41(1) C(18A) 1167(1) 4187(1) 1627(1) 39(1)
Molecule B N(1B) 4060(1) 4475(1) 3855(1) 39(1) N(2B) 3419(1) 6392(1) 2284(1) 30(1) N(3B) 2515(1) 7441(1) 1155(1) 37(1) C(1B) 3628(1) 4958(1) 3255(1) 33(1) C(2B) 2999(1) 4641(1) 3049(1) 39(1) C(3B) 2805(1) 3788(1) 3472(1) 46(1) C(4B) 3243(1) 3284(1) 4085(1) 47(1) C(5B) 3867(1) 3651(1) 4264(1) 44(1) C(6B) 4363(1) 3151(2) 4945(1) 65(1) C(7B) 3860(1) 5869(1) 2816(1) 32(1) C(8B) 3605(1) 7230(1) 1876(1) 31(1) C(9B) 4250(1) 7573(1) 2001(1) 37(1) C(10B) 4701(1) 6994(1) 2558(1) 42(1) C(11B) 4512(1) 6144(1) 2965(1) 39(1) C(12B) 3126(1) 7794(1) 1287(1) 34(1) C(13B) 3314(1) 8677(1) 863(1) 42(1) C(14B) 3972(1) 8997(1) 1017(1) 50(1) C(15B) 4419(1) 8473(1) 1562(1) 47(1) C(16B) 2093(1) 7951(1) 593(1) 47(1) C(17B) 2230(1) 8829(1) 137(1) 54(1) C(18B) 2843(1) 9194(1) 280(1) 53(1)
Molecule C N(1C) 3577(1) 2249(1) 2002(1) 36(1) N(2C) 3007(1) 4271(1) 496(1) 31(1) N(3C) 2129(1) 5426(1) -586(1) 39(1) C(1C) 3166(1) 2806(1) 1435(1) 32(1) C(2C) 2523(1) 2543(1) 1205(1) 39(1) C(3C) 2300(1) 1689(1) 1583(1) 48(1) C(4C) 2717(1) 1120(1) 2175(1) 47(1) C(5C) 3353(1) 1421(1) 2369(1) 41(1) C(6C) 3826(1) 817(2) 3006(1) 58(1)
118
C(7C) 3424(1) 3731(1) 1049(1) 31(1) C(8C) 3217(1) 5112(1) 113(1) 29(1) C(9C) 3867(1) 5420(1) 262(1) 31(1) C(10C) 4293(1) 4836(1) 856(1) 35(1) C(11C) 4076(1) 4002(1) 1257(1) 36(1) C(12C) 2755(1) 5708(1) -478(1) 31(1) C(13C) 2972(1) 6568(1) -910(1) 34(1) C(14C) 3639(1) 6840(1) -749(1) 36(1) C(15C) 4064(1) 6299(1) -186(1) 36(1) C(16C) 1718(1) 5989(1) -1116(1) 47(1) C(17C) 1884(1) 6853(1) -1572(1) 48(1) C(18C) 2517(1) 7134(1) -1471(1) 43(1)
Bond lengths [Å] and angles [°] for C18H13N3 ________________________________________________________________________N(1A)-C(5A) 1.3388(19) N(1A)-C(1A) 1.3453(18) N(2A)-C(7A) 1.3300(17) N(2A)-C(8A) 1.3532(17) N(3A)-C(16A) 1.3280(18) N(3A)-C(12A) 1.3602(18) C(1A)-C(2A) 1.391(2) C(1A)-C(7A) 1.4885(19) C(2A)-C(3A) 1.385(2) C(3A)-C(4A) 1.380(2) C(4A)-C(5A) 1.386(2) C(5A)-C(6A) 1.502(2) C(7A)-C(11A) 1.4090(19) C(8A)-C(9A) 1.4161(18) C(8A)-C(12A) 1.4567(19) C(9A)-C(10A) 1.405(2) C(9A)-C(15A) 1.428(2) C(10A)-C(11A) 1.363(2)
C(12A)-C(13A) 1.4155(19) C(13A)-C(18A) 1.406(2) C(13A)-C(14A) 1.432(2) C(14A)-C(15A) 1.346(2) C(16A)-C(17A) 1.402(2) C(17A)-C(18A) 1.365(2) N(1B)-C(5B) 1.342(2) N(1B)-C(1B) 1.3451(19) N(2B)-C(7B) 1.3294(18) N(2B)-C(8B) 1.3502(18) N(3B)-C(16B) 1.320(2) N(3B)-C(12B) 1.3566(19) C(1B)-C(2B) 1.382(2) C(1B)-C(7B) 1.488(2) C(2B)-C(3B) 1.384(2) C(3B)-C(4B) 1.378(2) C(4B)-C(5B) 1.392(3) C(5B)-C(6B) 1.505(2)
119
C(7B)-C(11B) 1.408(2) C(8B)-C(9B) 1.418(2) C(8B)-C(12B) 1.450(2) C(9B)-C(10B) 1.402(2) C(9B)-C(15B) 1.429(2) C(10B)-C(11B) 1.365(2)
C(12B)-C(13B) 1.413(2) C(13B)-C(18B) 1.404(3) C(13B)-C(14B) 1.435(3) C(14B)-C(15B) 1.349(3) C(16B)-C(17B) 1.399(2) C(17B)-C(18B) 1.365(3)
N(1C)-C(5C) 1.3415(19) N(1C)-C(1C) 1.3437(19) N(2C)-C(7C) 1.3267(18) N(2C)-C(8C) 1.3556(17) N(3C)-C(16C) 1.321(2) N(3C)-C(12C) 1.3567(18) C(1C)-C(2C) 1.392(2) C(1C)-C(7C) 1.4905(19) C(2C)-C(3C) 1.378(2) C(3C)-C(4C) 1.380(2) C(4C)-C(5C) 1.388(2) C(5C)-C(6C) 1.507(2)
C(7C)-C(11C) 1.411(2) C(8C)-C(9C) 1.4157(19) C(8C)-C(12C) 1.4516(19) C(9C)-C(10C) 1.403(2) C(9C)-C(15C) 1.4328(19) C(10C)-C(11C) 1.365(2) C(12C)-C(13C) 1.4154(19) C(13C)-C(18C) 1.399(2) C(13C)-C(14C) 1.437(2) C(14C)-C(15C) 1.346(2) C(16C)-C(17C) 1.400(2) C(17C)-C(18C) 1.371(2)
C(5A)-N(1A)-C(1A) 118.42(13) C(7A)-N(2A)-C(8A) 118.44(12) C(16A)-N(3A)-C(12A) 117.12(13) N(1A)-C(1A)-C(2A) 122.81(13) N(1A)-C(1A)-C(7A) 116.21(12) C(2A)-C(1A)-C(7A) 120.98(12) C(3A)-C(2A)-C(1A) 118.26(14) C(4A)-C(3A)-C(2A) 118.91(15) C(3A)-C(4A)-C(5A) 119.70(14) N(1A)-C(5A)-C(4A) 121.87(14) N(1A)-C(5A)-C(6A) 116.67(15) C(4A)-C(5A)-C(6A) 121.46(15) N(2A)-C(7A)-C(11A) 123.07(13) N(2A)-C(7A)-C(1A) 116.94(12) C(11A)-C(7A)-C(1A) 119.99(12) N(2A)-C(8A)-C(9A) 122.28(12)
N(2A)-C(8A)-C(12A) 119.06(12) C(9A)-C(8A)-C(12A) 118.66(12) C(10A)-C(9A)-C(8A) 117.47(13) C(10A)-C(9A)-C(15A) 121.92(13) C(8A)-C(9A)-C(15A) 120.61(13) C(11A)-C(10A)-C(9A) 120.13(13) C(10A)-C(11A)-C(7A) 118.59(13) N(3A)-C(12A)-C(13A) 122.44(13) N(3A)-C(12A)-C(8A) 118.91(12) C(13A)-C(12A)-C(8A) 118.64(12) C(18A)-C(13A)-C(12A) 117.91(13) C(18A)-C(13A)-C(14A) 121.84(13) C(12A)-C(13A)-C(14A) 120.24(13) C(15A)-C(14A)-C(13A) 121.19(13) C(14A)-C(15A)-C(9A) 120.62(13) N(3A)-C(16A)-C(17A) 124.58(14)
120
C(18A)-C(17A)-C(16A) 118.31(14) C(17A)-C(18A)-C(13A) 119.62(13) C(5B)-N(1B)-C(1B) 118.15(14) C(7B)-N(2B)-C(8B) 118.52(12) C(16B)-N(3B)-C(12B) 117.14(14) N(1B)-C(1B)-C(2B) 122.67(14) N(1B)-C(1B)-C(7B) 116.56(13) C(2B)-C(1B)-C(7B) 120.77(13) C(1B)-C(2B)-C(3B) 118.83(15) C(4B)-C(3B)-C(2B) 119.07(16) C(3B)-C(4B)-C(5B) 118.94(15) N(1B)-C(5B)-C(4B) 122.33(15) N(1B)-C(5B)-C(6B) 116.14(16) C(4B)-C(5B)-C(6B) 121.51(16) N(2B)-C(7B)-C(11B) 122.88(14) N(2B)-C(7B)-C(1B) 116.29(12) C(11B)-C(7B)-C(1B) 120.82(13) N(2B)-C(8B)-C(9B) 122.42(14)
N(2B)-C(8B)-C(12B) 118.53(12) C(9B)-C(8B)-C(12B) 119.05(13) C(10B)-C(9B)-C(8B) 117.32(14) C(10B)-C(9B)-C(15B) 122.55(15) C(8B)-C(9B)-C(15B) 120.13(15) C(11B)-C(10B)-C(9B) 120.10(14) C(10B)-C(11B)-C(7B) 118.74(15) N(3B)-C(12B)-C(13B) 122.66(15) N(3B)-C(12B)-C(8B) 118.35(13) C(13B)-C(12B)-C(8B) 118.99(14) C(18B)-C(13B)-C(12B) 117.66(16) C(18B)-C(13B)-C(14B) 122.48(15) C(12B)-C(13B)-C(14B) 119.83(16) C(15B)-C(14B)-C(13B) 121.34(15) C(14B)-C(15B)-C(9B) 120.66(16) N(3B)-C(16B)-C(17B) 124.67(17) C(18B)-C(17B)-C(16B) 118.25(17) C(17B)-C(18B)-C(13B) 119.60(16)
C(5C)-N(1C)-C(1C) 118.32(13) C(7C)-N(2C)-C(8C) 118.73(12) C(16C)-N(3C)-C(12C) 117.32(13) N(1C)-C(1C)-C(2C) 122.44(13) N(1C)-C(1C)-C(7C) 117.32(13) C(2C)-C(1C)-C(7C) 120.23(13) C(3C)-C(2C)-C(1C) 118.67(15) C(2C)-C(3C)-C(4C) 119.24(16) C(3C)-C(4C)-C(5C) 119.07(15) N(1C)-C(5C)-C(4C) 122.25(15) N(1C)-C(5C)-C(6C) 117.02(15) C(4C)-C(5C)-C(6C) 120.73(15) N(2C)-C(7C)-C(11C) 122.56(13) N(2C)-C(7C)-C(1C) 116.12(12) C(11C)-C(7C)-C(1C) 121.32(13) N(2C)-C(8C)-C(9C) 122.33(13) N(2C)-C(8C)-C(12C) 118.41(12)
C(9C)-C(8C)-C(12C) 119.27(12) C(10C)-C(9C)-C(8C) 117.35(13) C(10C)-C(9C)-C(15C) 122.92(13) C(8C)-C(9C)-C(15C) 119.73(13) C(11C)-C(10C)-C(9C) 120.06(13) C(10C)-C(11C)-C(7C) 118.93(14) N(3C)-C(12C)-C(13C) 122.43(13) N(3C)-C(12C)-C(8C) 118.55(12) C(13C)-C(12C)-C(8C) 119.02(13) C(18C)-C(13C)-C(12C) 117.93(13) C(18C)-C(13C)-C(14C) 122.43(13) C(12C)-C(13C)-C(14C) 119.64(14) C(15C)-C(14C)-C(13C) 121.27(13) C(14C)-C(15C)-C(9C) 121.05(13) N(3C)-C(16C)-C(17C) 124.62(15) C(18C)-C(17C)-C(16C) 118.12(15) C(17C)-C(18C)-C(13C) 119.57(14)
121
________________________________________________________________________ Anisotropic displacement parameters (Å2x 103) for C18H13N3. The anisotropic displacement factor exponent takes the form: -2π2[ h2a*2U11 + ... + 2 h k a* b* U12 ] ________________________________________________________________________ U11 U22 U33 U23 U13 U12
Molecule A N(1A) 37(1) 35(1) 36(1) 3(1) 7(1) 6(1) N(2A) 29(1) 29(1) 31(1) 1(1) 2(1) -1(1) N(3A) 31(1) 38(1) 40(1) -2(1) 7(1) -5(1) C(1A) 32(1) 32(1) 29(1) 4(1) 1(1) 4(1) C(2A) 31(1) 38(1) 36(1) 0(1) 0(1) 1(1) C(3A) 40(1) 38(1) 45(1) -4(1) -5(1) -2(1) C(4A) 49(1) 39(1) 39(1) -7(1) -1(1) 7(1) C(5A) 45(1) 38(1) 36(1) 4(1) 5(1) 12(1) C(6A) 63(1) 50(1) 60(1) -1(1) 26(1) 14(1) C(7A) 28(1) 30(1) 30(1) 4(1) 1(1) 3(1) C(8A) 27(1) 29(1) 29(1) 3(1) -1(1) -1(1) C(9A) 30(1) 29(1) 33(1) 3(1) -2(1) -3(1) C(10A) 33(1) 33(1) 46(1) 6(1) 6(1) -6(1) C(11A) 30(1) 38(1) 41(1) 5(1) 8(1) 0(1) C(12A) 29(1) 31(1) 30(1) 0(1) 0(1) 0(1) C(13A) 32(1) 34(1) 30(1) -1(1) -2(1) 5(1) C(14A) 44(1) 28(1) 34(1) -4(1) -3(1) 2(1) C(15A) 39(1) 29(1) 38(1) 0(1) -3(1) -6(1) C(16A) 31(1) 45(1) 42(1) -1(1) 8(1) -4(1) C(17A) 30(1) 55(1) 37(1) -3(1) 6(1) 4(1) C(18A) 37(1) 42(1) 35(1) -7(1) -1(1) 8(1)
Molecule B N(1B) 38(1) 44(1) 36(1) 1(1) 6(1) 10(1) N(2B) 29(1) 31(1) 32(1) -3(1) 7(1) 0(1) N(3B) 33(1) 41(1) 40(1) 2(1) 10(1) 5(1) C(1B) 35(1) 33(1) 30(1) -5(1) 5(1) 4(1) C(2B) 37(1) 38(1) 40(1) 2(1) -2(1) -2(1)
122
C(3B) 47(1) 44(1) 46(1) -1(1) 5(1) -10(1) C(4B) 59(1) 40(1) 43(1) 6(1) 15(1) 0(1) C(5B) 50(1) 46(1) 38(1) 6(1) 12(1) 12(1) C(6B) 57(1) 75(1) 62(1) 28(1) 11(1) 17(1) C(7B) 30(1) 33(1) 34(1) -8(1) 6(1) 2(1) C(8B) 32(1) 30(1) 33(1) -6(1) 11(1) -2(1) C(9B) 34(1) 36(1) 41(1) -11(1) 12(1) -7(1) C(10B) 30(1) 44(1) 52(1) -15(1) 7(1) -6(1) C(11B) 30(1) 39(1) 45(1) -9(1) 0(1) 3(1) C(12B) 37(1) 33(1) 35(1) -3(1) 13(1) 1(1) C(13B) 51(1) 36(1) 42(1) 1(1) 17(1) 0(1) C(14B) 61(1) 39(1) 55(1) 3(1) 22(1) -13(1) C(15B) 45(1) 44(1) 53(1) -6(1) 16(1) -14(1) C(16B) 40(1) 53(1) 47(1) 4(1) 9(1) 12(1) C(17B) 59(1) 54(1) 51(1) 13(1) 12(1) 21(1) C(18B) 68(1) 42(1) 51(1) 12(1) 20(1) 7(1)
Molecule C N(1C) 35(1) 38(1) 37(1) 7(1) 9(1) 4(1) N(2C) 30(1) 30(1) 32(1) 1(1) 6(1) 0(1) N(3C) 32(1) 36(1) 48(1) 8(1) 2(1) -4(1) C(1C) 33(1) 33(1) 32(1) -1(1) 8(1) 3(1) C(2C) 33(1) 40(1) 42(1) 4(1) 3(1) 0(1) C(3C) 40(1) 48(1) 56(1) 6(1) 6(1) -9(1) C(4C) 49(1) 40(1) 54(1) 11(1) 13(1) -6(1) C(5C) 42(1) 41(1) 41(1) 8(1) 13(1) 6(1) C(6C) 54(1) 58(1) 61(1) 27(1) 11(1) 6(1) C(7C) 31(1) 32(1) 30(1) -2(1) 6(1) 1(1) C(8C) 30(1) 29(1) 29(1) -2(1) 8(1) -2(1) C(9C) 30(1) 31(1) 32(1) -6(1) 7(1) -1(1) C(10C) 28(1) 37(1) 40(1) -5(1) 4(1) -3(1) C(11C) 31(1) 36(1) 38(1) 1(1) 0(1) 3(1) C(12C) 32(1) 30(1) 33(1) -1(1) 8(1) -2(1) C(13C) 37(1) 33(1) 34(1) 0(1) 10(1) -2(1) C(14C) 39(1) 33(1) 39(1) 4(1) 13(1) -7(1) C(15C) 32(1) 38(1) 40(1) -4(1) 10(1) -7(1) C(16C) 33(1) 46(1) 59(1) 11(1) -2(1) -4(1)
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C(17C) 40(1) 46(1) 55(1) 16(1) -2(1) 1(1) C(18C) 46(1) 39(1) 44(1) 11(1) 8(1) -3(1)
Table 5. Hydrogen coordinates ( x 104) and isotropic displacement parameters (Å2x 103) for C18H13N3 ________________________________________________________________________ x y z U(eq) ________________________________________________________________________
Molecule A H(2A) 533 7739 4567 42 H(3A) 475 9213 5431 51 H(4A) -402 9437 6230 52 H(6AA) -1293 8659 6871 84 H(6AB) -1528 7555 6551 84 H(6AC) -1774 8512 5947 84 H(10A) -1051 4081 3959 45 H(11A) -1091 5552 4794 43 H(14A) 294 2850 2000 44 H(15A) -496 3025 2905 43 H(16A) 1789 6385 2007 47 H(17A) 1883 4945 1139 49 H(18A) 1204 3588 1288 46
Molecule B H(2B) 2706 5001 2624 47 H(3B) 2375 3553 3340 55 H(4B) 3120 2695 4381 56 H(6BA) 4769 3518 4977 97 H(6BB) 4426 2456 4756 97 H(6BC) 4216 3153 5545 97 H(10B) 5139 7194 2653 50 H(11B) 4816 5746 3342 47 H(14B) 4095 9591 729 60 H(15B) 4851 8703 1655 56
124
H(16B) 1665 7703 490 56 H(17B) 1906 9163 -262 65 H(18B) 2950 9794 -14 63
Molecule C H(2C) 2245 2945 795 46 H(3C) 1863 1493 1439 58 H(4C) 2571 531 2447 56 H(6CA) 3609 226 3218 86 H(6CB) 3995 1233 3529 86 H(6CC) 4180 598 2685 86 H(10C) 4733 5020 978 42 H(11C) 4360 3611 1670 43 H(14C) 3783 7413 -1046 44 H(15C) 4501 6502 -85 43 H(16C) 1279 5796 -1193 56 H(17C) 1566 7233 -1942 57 H(18C) 2647 7708 -1781 51
Table 6. Torsion angles [°] for C18H13N3 ________________________________________________________________ C(5A)-N(1A)-C(1A)-C(2A) -0.9(2) C(5A)-N(1A)-C(1A)-C(7A) 178.98(12) N(1A)-C(1A)-C(2A)-C(3A) -0.4(2) C(7A)-C(1A)-C(2A)-C(3A) 179.77(13) C(1A)-C(2A)-C(3A)-C(4A) 0.9(2) C(2A)-C(3A)-C(4A)-C(5A) -0.2(2) C(1A)-N(1A)-C(5A)-C(4A) 1.7(2) C(1A)-N(1A)-C(5A)-C(6A) -177.91(14) C(3A)-C(4A)-C(5A)-N(1A) -1.1(2) C(3A)-C(4A)-C(5A)-C(6A) 178.40(15) C(8A)-N(2A)-C(7A)-C(11A) -0.9(2) C(8A)-N(2A)-C(7A)-C(1A) 178.23(11) N(1A)-C(1A)-C(7A)-N(2A) 171.88(12) C(2A)-C(1A)-C(7A)-N(2A) -8.24(19)
125
N(1A)-C(1A)-C(7A)-C(11A) -8.92(19) C(2A)-C(1A)-C(7A)-C(11A) 170.96(13) C(7A)-N(2A)-C(8A)-C(9A) 0.04(19) C(7A)-N(2A)-C(8A)-C(12A) -179.98(11) N(2A)-C(8A)-C(9A)-C(10A) 1.1(2) C(12A)-C(8A)-C(9A)-C(10A) -178.87(12) N(2A)-C(8A)-C(9A)-C(15A) -177.91(12) C(12A)-C(8A)-C(9A)-C(15A) 2.1(2) C(8A)-C(9A)-C(10A)-C(11A) -1.4(2) C(15A)-C(9A)-C(10A)-C(11A) 177.63(14) C(9A)-C(10A)-C(11A)-C(7A) 0.6(2) N(2A)-C(7A)-C(11A)-C(10A) 0.7(2) C(1A)-C(7A)-C(11A)-C(10A) -178.49(13) C(16A)-N(3A)-C(12A)-C(13A) 1.0(2) C(16A)-N(3A)-C(12A)-C(8A) -178.08(13) N(2A)-C(8A)-C(12A)-N(3A) -2.12(19) C(9A)-C(8A)-C(12A)-N(3A) 177.86(13) N(2A)-C(8A)-C(12A)-C(13A) 178.81(12) C(9A)-C(8A)-C(12A)-C(13A) -1.21(19) N(3A)-C(12A)-C(13A)-C(18A) -1.0(2) C(8A)-C(12A)-C(13A)-C(18A) 178.06(12) N(3A)-C(12A)-C(13A)-C(14A) -179.70(13) C(8A)-C(12A)-C(13A)-C(14A) -0.7(2) C(18A)-C(13A)-C(14A)-C(15A) -176.93(14) C(12A)-C(13A)-C(14A)-C(15A) 1.7(2) C(13A)-C(14A)-C(15A)-C(9A) -0.9(2) C(10A)-C(9A)-C(15A)-C(14A) 179.93(14) C(8A)-C(9A)-C(15A)-C(14A) -1.1(2) C(12A)-N(3A)-C(16A)-C(17A) 0.0(2) N(3A)-C(16A)-C(17A)-C(18A) -0.9(2) C(16A)-C(17A)-C(18A)-C(13A) 0.9(2) C(12A)-C(13A)-C(18A)-C(17A) 0.0(2) C(14A)-C(13A)-C(18A)-C(17A) 178.72(14) C(5B)-N(1B)-C(1B)-C(2B) 0.2(2) C(5B)-N(1B)-C(1B)-C(7B) -179.98(12) N(1B)-C(1B)-C(2B)-C(3B) -0.4(2)
126
C(7B)-C(1B)-C(2B)-C(3B) 179.79(13) C(1B)-C(2B)-C(3B)-C(4B) 0.1(2) C(2B)-C(3B)-C(4B)-C(5B) 0.3(2) C(1B)-N(1B)-C(5B)-C(4B) 0.3(2) C(1B)-N(1B)-C(5B)-C(6B) -178.69(14) C(3B)-C(4B)-C(5B)-N(1B) -0.5(2) C(3B)-C(4B)-C(5B)-C(6B) 178.39(16) C(8B)-N(2B)-C(7B)-C(11B) -0.6(2) C(8B)-N(2B)-C(7B)-C(1B) 179.40(11) N(1B)-C(1B)-C(7B)-N(2B) -174.37(12) C(2B)-C(1B)-C(7B)-N(2B) 5.47(19) N(1B)-C(1B)-C(7B)-C(11B) 5.65(19) C(2B)-C(1B)-C(7B)-C(11B) -174.50(14) C(7B)-N(2B)-C(8B)-C(9B) -0.49(19) C(7B)-N(2B)-C(8B)-C(12B) 179.17(12) N(2B)-C(8B)-C(9B)-C(10B) 1.2(2) C(12B)-C(8B)-C(9B)-C(10B) -178.47(12) N(2B)-C(8B)-C(9B)-C(15B) -179.20(13) C(12B)-C(8B)-C(9B)-C(15B) 1.1(2) C(8B)-C(9B)-C(10B)-C(11B) -0.8(2) C(15B)-C(9B)-C(10B)-C(11B) 179.62(14) C(9B)-C(10B)-C(11B)-C(7B) -0.2(2) N(2B)-C(7B)-C(11B)-C(10B) 1.0(2) C(1B)-C(7B)-C(11B)-C(10B) -179.02(13) C(16B)-N(3B)-C(12B)-C(13B) 1.2(2) C(16B)-N(3B)-C(12B)-C(8B) -177.91(13) N(2B)-C(8B)-C(12B)-N(3B) -1.43(19) C(9B)-C(8B)-C(12B)-N(3B) 178.25(12) N(2B)-C(8B)-C(12B)-C(13B) 179.46(12) C(9B)-C(8B)-C(12B)-C(13B) -0.86(19) N(3B)-C(12B)-C(13B)-C(18B) -0.5(2) C(8B)-C(12B)-C(13B)-C(18B) 178.58(14) N(3B)-C(12B)-C(13B)-C(14B) -178.74(14) C(8B)-C(12B)-C(13B)-C(14B) 0.3(2) C(18B)-C(13B)-C(14B)-C(15B) -178.23(16) C(12B)-C(13B)-C(14B)-C(15B) -0.1(3)
127
C(13B)-C(14B)-C(15B)-C(9B) 0.3(3) C(10B)-C(9B)-C(15B)-C(14B) 178.71(15) C(8B)-C(9B)-C(15B)-C(14B) -0.9(2) C(12B)-N(3B)-C(16B)-C(17B) -0.9(2) N(3B)-C(16B)-C(17B)-C(18B) -0.1(3) C(16B)-C(17B)-C(18B)-C(13B) 0.8(3) C(12B)-C(13B)-C(18B)-C(17B) -0.5(2) C(14B)-C(13B)-C(18B)-C(17B) 177.66(16) C(5C)-N(1C)-C(1C)-C(2C) -1.2(2) C(5C)-N(1C)-C(1C)-C(7C) 179.03(12) N(1C)-C(1C)-C(2C)-C(3C) 1.0(2) C(7C)-C(1C)-C(2C)-C(3C) -179.24(14) C(1C)-C(2C)-C(3C)-C(4C) -0.1(2) C(2C)-C(3C)-C(4C)-C(5C) -0.5(3) C(1C)-N(1C)-C(5C)-C(4C) 0.5(2) C(1C)-N(1C)-C(5C)-C(6C) -179.60(14) C(3C)-C(4C)-C(5C)-N(1C) 0.3(3) C(3C)-C(4C)-C(5C)-C(6C) -179.56(16) C(8C)-N(2C)-C(7C)-C(11C) 0.3(2) C(8C)-N(2C)-C(7C)-C(1C) -178.94(11) N(1C)-C(1C)-C(7C)-N(2C) -179.57(12) C(2C)-C(1C)-C(7C)-N(2C) 0.65(19) N(1C)-C(1C)-C(7C)-C(11C) 1.14(19) C(2C)-C(1C)-C(7C)-C(11C) -178.64(13) C(7C)-N(2C)-C(8C)-C(9C) 1.70(19) C(7C)-N(2C)-C(8C)-C(12C) -178.89(12) N(2C)-C(8C)-C(9C)-C(10C) -2.14(19) C(12C)-C(8C)-C(9C)-C(10C) 178.46(12) N(2C)-C(8C)-C(9C)-C(15C) 177.91(12) C(12C)-C(8C)-C(9C)-C(15C) -1.49(19) C(8C)-C(9C)-C(10C)-C(11C) 0.5(2) C(15C)-C(9C)-C(10C)-C(11C) -179.52(13) C(9C)-C(10C)-C(11C)-C(7C) 1.4(2) N(2C)-C(7C)-C(11C)-C(10C) -1.9(2) C(1C)-C(7C)-C(11C)-C(10C) 177.36(12) C(16C)-N(3C)-C(12C)-C(13C) -0.1(2)
128
C(16C)-N(3C)-C(12C)-C(8C) 179.02(14) N(2C)-C(8C)-C(12C)-N(3C) 3.15(19) C(9C)-C(8C)-C(12C)-N(3C) -177.43(12) N(2C)-C(8C)-C(12C)-C(13C) -177.69(12) C(9C)-C(8C)-C(12C)-C(13C) 1.74(19) N(3C)-C(12C)-C(13C)-C(18C) -0.5(2) C(8C)-C(12C)-C(13C)-C(18C) -179.63(13) N(3C)-C(12C)-C(13C)-C(14C) 178.50(13) C(8C)-C(12C)-C(13C)-C(14C) -0.6(2) C(18C)-C(13C)-C(14C)-C(15C) 178.18(14) C(12C)-C(13C)-C(14C)-C(15C) -0.8(2) C(13C)-C(14C)-C(15C)-C(9C) 1.1(2) C(10C)-C(9C)-C(15C)-C(14C) -179.85(14) C(8C)-C(9C)-C(15C)-C(14C) 0.1(2) C(12C)-N(3C)-C(16C)-C(17C) 0.1(3) N(3C)-C(16C)-C(17C)-C(18C) 0.5(3) C(16C)-C(17C)-C(18C)-C(13C) -1.2(3) C(12C)-C(13C)-C(18C)-C(17C) 1.1(2) C(14C)-C(13C)-C(18C)-C(17C) -177.83(15) ________________________________________________________________________
129
APPENDIX B
UV-visible spectra
130
358
291
237
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
200 250 300 350 400
wavelength (nm)
Abs
Compound (3), 3.0 x 10-5 M in MeOH
237
358
292
-0.05
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
220 270 320 370 420
wavelength (nm)
Abs
Compound (4), 1.7 x 10-5 M in MeOH
NN
OOMe
NN
OOBn
131
359
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
250 270 290 310 330 350 370 390
wavelength (nm)
Abs
Compound (4)-CuSO4 complex, 5.9 x 10-5 M in H2O
254295
-0.1
0
0.1
0.2
0.3
0.4
0.5
210 230 250 270 290 310 330 350 370 390
wavelength (nm)
Abs
Compound (8), 5.2 x 10-6 M in MeOH
NN
OBn
O
O
O
132
258
295
-0.05
0.05
0.15
0.25
0.35
0.45
0.55
0.65
220 240 260 280 300 320 340 360
wavelength (nm)
Abs
Compound (11), 2.7 x 10-5 M in MeOH
291
257
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
220 240 260 280 300 320 340
wavelength (nm)
Abs
Compound (11)-CuSO4 complex, 4.2 x 10-5 M in H2O
NN
N
N
OBn
O
133
258
294
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
220 240 260 280 300 320 340 360
wavelength (nm)
Abs
Compound (11)-CoSO4 complex, 4.1 x 10-5 M in H2O
295
258
0
0.1
0.2
0.3
0.4
0.5
0.6
220 240 260 280 300 320 340 360
wavelength (nm)
Abs
Compound (11)-NiSO4 complex, 5.3 x 10-5 M in H2O
134
292
256
0
0.1
0.2
0.3
0.4
0.5
0.6
200 250 300 350 400 450 500
wavelength (nm)
Abs
Compound (11)-Fe2(SO4)3 complex, 4.1 x 10-5 M in H2O
296
258
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
220 240 260 280 300 320 340 360
wavelength (nm)
Abs
Compound (11)-ZnSO4 complex, 4.4 x 10-5 M in H2O
135
310
271
0
0.1
0.2
0.3
0.4
0.5
0.6
200 250 300 350 400 450
wavelength (nm)
Abs
orba
nce
Compound (13) and CuSO4 complex, 2.8 x 10-5 M in H2O
N
N
CO2Et
EtO2C 2+Cu
136
SCHOLASTIC VITA
ERIC STEPHEN OSHIGE
BORN: August 12, 1981, Spartanburg, SC UNDERGRADUATE STUDY: University of South Carolina-Spartanburg B.S., Chemistry, 2003 GRADUATE STUDY: Wake Forest University Winston-Salem, North Carolina M.S. Candidate, Spring 2007 SCHOLASTIC AND PROFESSIONAL EXPERIENCE: Research Assistant, Wake Forest University, 2006-2007 Teaching Assistant, Wake Forest University, 2005 Laboratory Technician, Milliken Chemical, 2003-2004 Intern, Metal-Chem, Inc., 2002-2003 HONORS AND AWARDS: Travel award to the National Meeting of the American Chemical Society, Atlanta,
GA, March 2006. GlaxoSmithKline Fellowship, Wake Forest University, 2004-2005. Outstanding Senior Chemistry Major, University of South Carolina-Spartanburg
and the Western Carolinas Section of the ACS, 2003. Chancellor’s Scholarship, University of South Carolina-Spartanburg, 1999-2003. South Carolina Palmetto Fellows Scholarship, 1999-2003. PROFESSIONAL SOCIETIES: American Chemical Society, 2001-2006. PUBLICATIONS:
Oshige, E.S., and Jones, P.B. “Photoactivated artificial metalloesterases.” Submitted to J. Photochem. Photobiol. A: Chemistry, April 2007.
137
PRESENTATIONS:
Oshige, E.S. and Jones, P.B. “The synthesis and investigation of photoactivated artificial metalloproteases.” Graduate Student Research Day, Wake Forest University, March 24, 2006.
Oshige, E.S. and Jones, P.B. “The synthesis and investigation of photoactivated
artificial metalloproteases.” National Meeting of the American Chemical Society, Atlanta, GA, March 26 and 27, 2006.
Oshige, E.S. and Jones, P.B. “The synthesis and investigation of photoactivated artificial metalloproteases.” Central NC ACS Poster Session, Greensboro, NC, April 4, 2006. Oshige, E.S. and Jones, P.B. “Photorelease of Caged Alcohols from Metal Complexes.” Southeastern Meeting of the American Chemical Society, Augusta, GA, November 1, 2006.