peter j. stang baran group meeting 07/09/16 · ruben martinez peter j. stang baran group meeting...

Peter J. StangRuben MartinezBaran Group Meeting

07/09/16

Peter J. StangDistinguished Professor of ChemistryDepartment of Chemistry, University of Utah

"I am very humbled, honored and pleased. To date, I have had approximately 100 postdoctoral and Ph.D. students as well as some undergraduate researchers whom I mentored, and this recognizes their work too." - Peter J. Stang

Professor Stang was named by President Obama as a recipient of the National Medal of Science, the highest honor bestowed by the U.S. Government on a scientist or engineer.

Professor Stang was cited by the White House "for his creative contributions to the development of organic supramolecular chemistry and for his outstanding and unique record of public service.

• David P. Gardner Presidential Chair, University of Utah (2014)• Priestley Medal (2013)• National Medal of Science (2011)• Paul G. Gassman Distinguished Service Award (2010)• F. A. Cotton Medal for Excellence in Chemical Research (2010)• Fred Basolo Medal for Outstanding Research in Inorganic Chemistry (2009)• ACS Award for Creative Research and Applications of Iodine Chem. (2007)• Foreign Member, Hungarian Academy of Sciences (2007)• Linus Pauling Medal (2006)• Foreign Member, Chinese Academy of Sciences (2006)• George A. Olah Award in Hydrocarbon Chemistry (2003)• Member, National Academy of Sciences (2000)

• B. S., 1963 DePaul University• Ph.D., 1966, University of California, Berkeley• NIH Postdoctoral Fellow, 1967–68, Princeton

• Associate Editor, JACS (1982–1999)• Editor-in-Chief, JACS (2002–present)

• Editor-in-Chief, J. Org. Chem. (2000–2001)• Born 1941 in Nuremberg, Germany• Raised in Hungary until 1956• Family fled to U.S. due to Soviet invasion of Hungary and settled in Chicago• Married wife in 1969• Two daughters in medical field

"This is the only country in the world that I know of that takes the best of anyone in the world and gives them the opportunity to succeed." -Peter J. Stang

Short list of awards and honors

• Author of more than 450 scientific publications, several books and over two-dozen widely cited reviews.• Early research involved unsaturated reactive intermediates like vinyl cations and unsaturated carbenes.• Major contributions to polyvalent iodine chemistry, alkynyl iodonium salts.• Current research interests are in supramolecular chemisty

"This award also indicates that it is possible to do cutting-edge world-class research at the University of Utah."

National Medal of Science


07/09/16

Hypervalent Iodine

Preparation and Characterization of a Macrocyclic Tetraaryltetraiodonium CompoundJ. Am. Chem. Soc. 1993, 115 , 9808.

I ICF3CO3H

DCM, -78 °C to rt(F3CCO2)2I I(O2CCF3)2

A

SiMe3

SiMe3

+

2 equiv.

I I

SiMe3 SiMe3

2TfO

A

77%

86%

2 TMSOTf

I I

SiMe3 SiMe3

2TfO

I(O2CCF3)2

I(O2CCF3)2

I I

I I

4TfO

DCM, -78 °C10–15%

2 TMSOTfA+

For an excellent overview of hypervalent iodine chemistry see: Lo, Hypervalent Iodine GM 2013.

DCM, -78 °C to rt

Stang's Reagent Preparation: Tetrahedron Lett., 1990, 31, 4821.

PhI(OAc)2

1) TMSOTf2) TMSCN

85%NaOH

Ph IO Ph I

CN

OTf

Stang's ReagentThe primary use of Stang's reagent is in the conversion of alkenyl and alkynyl stannanes to the corresponding iodonium salts.

85%N

N

MeO

O

SnBu3

Me

87%N

N

MeO

O

IPhOTf

Me

Formation of Iodonium Salts

Tetrahedron 1999, 40, 1903.

SnBu3

Me

IPhOTf

Me

Stang'sreagent

Stang'sreagent

Tetrahedron Lett., 1993, 34, 6853.Cycloaddition with Alkynyliodonium SaltsJ. Org. Chem. 1997, 62, 5959.

Me

Me2N

O

IPhOTf+

Me O

NMe2

IPhOTf

MeCN, rt73%

OTfR

TfOPhI

OTfR

MeO+

H

OMe

PdCl2(PPh3)2,CuI, K2CO3,

Organometallic Chemistry with Iodonium SaltsTetrahedron 1999, 55, 12377.

Me

Me Me

IPhOTfPPh3 Me

Me Me

PPh3OTfMe

Me Me

PPh3OTf

98%

Conjugate Addition to Alkynyliodonium SaltsJ. Org. Chem. 1992, 57, 4305.

DCM

DMF/H2O, Et3N72%

Soft nucleophiles add in a conjugate fashion to alkynyliodonium salts to generate alkylidenecarbenes. Once formed, the alkylidenecarbene can follow three reaction pathways: 1,2-shift, 1,5-insertion, and alkene addition.

N

O

Bu3Sn SnBu3H

SnBu3

3 3 N

O

Bu3Sn SnBu3H3 3

SO2Tol

1) Stang's Reagent2) TolSO2Na

Alkynyliodonium Salts in Organic Synthesis.Application to the preparation of the tricyclic core of (±)-Halichlorine JOC 2004, 69, 7928.

NBu3Sn3

O SO2Tol

SnBu33

58%–65%scalable up to 14gN

H

OO

Cl OH

Me

halichlorine

N

EtO2C

H

Me

OHtricyclie halichlorine core


07/09/16Transition Metal Based Cationic Molecular BoxesJ. Am. Chem . Soc. 1994, 116 , 4981.

P

PM

Cl

Cl

M = Pt or Pd

AgOTfDCM, rt

P

PM

OTf

OTf

4,4'-bipyridine

DCM, rt

N NM MN N

N NM MN NPPPh2

PPPh2 Ph2P

P

PPh2P

Ph2 Ph2

Ph2Ph2

8 OTf

8

M = Pt or Pd

N NMN

N

PPPh2

Ph2

2

2 OTf

MN

NM

Ph2PP

PPh2P

Ph2

Ph2

TfO

TfO

2 OTf

Attempts to isolate or observe (NMR) precursors were unsuccessful.

DCM, rtN N

2 equiv.

+

Ph2

Ph2

Ph2

Ph2

self-assemblesin a matter ofminutes

P

PM

OTf

OTf

Ph2

Ph2

P

PM

N

N

Ph2

Ph2

N

N

2

2 OTf

M = Pt or Pdexclusive monomer formation

Coordination Chemistry

Fujita builds on Verkade's first exampleJ. Am. Chem. Soc. 1990, 112 , 5645.

Supramolecular Chemistry and Self AssemblyMetal–Organic Frameworks (MOFs): Infinite networks of metal centers or inorganic clusters bridged by simple organic linkers through metal–ligand coordination bonds

Supramolecular Coordination Complexes (SCCs): Discrete systems in which carefully selected metal centers undergo self-assembly with ligands containing multiple binding sites oriented with specific angularity to generate a finite supramolecular complex. Since coordination bonds are the impetus for formation, this process is called "coordination-driven self-assembly".

Chem. Rev. 2013, 113 , 734.Verkade's pioneering workJ. Am. Chem. Soc. 1983, 105 , 2494.


07/09/16Self-Assembly of Cationic, Tetranuclear, Pt(II) and Pd(II) SquaresJ. Am. Chem . Soc. 1995, 117 , 6273.

P

PM

OTf

OTf

Ph2

Ph2

Et3P

Et3PM

OTf

OTfvs.Is a cyclic bis(phosphine)

complex necessary to holdthe desired cis geometry required for self-assembly?

N NM MN N

N NM MN NPEt3

Et3P

Et3PEt3P PEt3

PEt3

PEt3PEt3

8 OTf

8

M = Pt (90%)M = Pd (89%)

Et3P

Et3PM

OTf

OTf

N

NMeNO2, rt

+

These novel metal-based molecular squares represent new materials with as yet unexplored unique properties. Uses envisioned include inclusion phenomena, catalyses, host–guest interactions with electron-rich and anionic guests,noncovalent interactions, and ultimately perhaps nano-scale molecular devices.

Directed Self-Assembly of Chiral, Optically Active Molecular SquaresAngew. Chem., Int. Ed. 1996, 35, 732.

M

L2P

PL2

OTf

OTf•H2O N

N

acetone, 25 °C

The design of chiral macromolecular assemblies requires an alternative approach to that used for the preparation of achiral square shaped species. Whereas the spatial orientation of the donor atoms (e.g. N) of the bidentate ligand may remain 180° relative to each other, the ligand should possess C2h symmetry as opposed to the D2d or D2h symmetrical diaza ligands used in molecular squares.

M = PdM = Pt L = Ph

M

L2P

PL2

OTf

OTf•H2O

NN

acetone, 25 °C

N

N N

N

N

NN

N

M

M

M

M

L2PPL2

PL2L2P

L2PPL2

L2P PL2

2

2

2

2

8 OTf

M = PdM = Pt L = Ph

+

M = Pd, 86%, [α]D = +441 (CH3COCH3)M = Pt, 84%, [α]D = +237 (CH3COCH3)L = Ph

Directed Self-Assembly of Chiral Molecular Squares cont.

Angew. Chem., Int. Ed. 1996, 35, 732.

self-assembly

Molecular Architecture via Coordination: Self-Assembly of Nanoscale HexagonsJ. Am. Chem. Soc. 1997, 119 , 4777.A rational design strategy and formation of molecular hexagons requires the following:1) Shape defining and directing corner units C with ca. 120° bond angles.2) Appropriate linkers L3) Proper self-assembly of the corners, C, with linkers, L

solvent6 C 6 L+

L

L

L

LL

LC

CC

C

CC

N N

O

N N

O

Pt PtPh3P

PPh3TfO

PPh3

Ph3P OTf 41 2

PtPt

PPh3

PPh3

OTf

PPh3

PPh3

TfO

1 + 2rt DCM, 30 min

3 + 4rt DCM, 15 min

3


07/09/16Molecular Architecture: Coordination as the Motif in the Rational Design and Assembly of Discrete Supramolecular Species—Self-Assembly of Metallycyclic Polygons Polyhedra.Chem. Eur. J. 1998, 4, 19.

Any convex polygon or canonical polyhedron can beconstructed with just two simple types of building blocks:1) Linear units (L) containing reactive sites with a 180° orientation relative to each other.2) Various angular units (A) possessing binding sites with the desirable (required) angular orientations.

Descriptor

Xyzdesignator (A or L)

denticity of unit

number of units required to form a specific polygon

N NN N

N N

n= 0,1,2n

CN C N

O

N NN N

N

N

N

N

Molecular Architecture cont: Building a library of linear and angular binding units

O

M MR3P

PR3TfO

PR3

R3P OTf MM

PR3

PR3

OTf

PR3

PR3

TfO

M = Pd, PtR = Et, Ph

M = Pd, PtR = Et, Ph

MM

PR3

PR3

OTf

PR3

PR3

TfO

Self-assembly of Nanoscale Cuboctahedra by Coordination ChemistryNature 1999, 398, 796.

The cuboctahedron is an archimedean semiregular polyhedron that combines square and triangular faces.

"In architectural terms the development of the coordination motif is only in the Romanesque period, with the Gothic, Baroque, Rococo and modern periods yet to come."

Pt

Pt Pt

OTfPPh3Ph3P

TfO

Ph3P

PPh3OTfPPh3

Ph3P

I

I

H

HH +

1) Pd(PPh3)4, CuI, Et3N, THF2) Pt(Ph3)4, PhMe3) AgOTf, DCM


07/09/16

Ph3P

PPh3

OTfPPh3

Ph3P

TfO

Ph3P PPh3OTf

PtPt

Pt

OO

+

=

=

Self-assembly of Nanoscale Cuboctahedra cont.Nature 1999, 398, 796.

HO

N

N

N

=20

=Pt

Pt

PR3R3P

R3P PR3OTf

OTf

n30

R = Et, n = 1, 99%, D = ca. 5.5 nmR = Ph, n = 2, 99%, D = ca. 4.5 nm

Self Assembly of Nanoscopic Dodecahedra from 50 Predesigned ComponentsJ. Am. Chem. Soc. 1999, 121 , 10434.

Insights into the Mechanism of Coordination-Directed Self-AssemblyJ. Am. Chem. Soc. 2000, 122 , 7428.

HO

N

N

N

Pt

Pt

PEt3Et3P

Et3P PEt3OTf

OTf

30

DCM

20

=

=

acetone

Self-correctionsyn config.

anti config

Growth of intermediates

OR

N

N

N

X

PtPtPEt3

Et3P OTf

Et3P

PEt3TfO

Rational Design of Chiral Nanoscale AdamantanoidsOrg. Lett. 2000, 2, 1255.

X = C(CH3)2 [109°]X = C=O [120°]

∗∗O

MeR =CD2Cl2

+


07/09/16

Self-assembly of Hexagonal Cavity-Cored Tris[2]pseudorotaxanesJ. Am. Chem. Soc. 2007, 129 , 14187.

O

O O

O

O

OO

O

O

N N

O

Pt PtEt3P

PEt3TfO

PEt3

Et3P OTf

Pt PtTfO

PEt3

PEt3 OTf

PEt3

Et3P

NH2or= = =

1

2

3 4

Responsive Supramolecular Polymer MetallogelJ. Am. Chem. Soc. 2014, 136 , 4460.

Pt PtTfO

PEt3

PEt3 OTf

PEt3

Et3P

OOO

O

O OO

O

O

N N3

2

=

=

O

NH2 N

NN

O

NH2N

N N

10PF6 PF6

=

4

I

peter j. stang baran group meeting 07/09/16 · ruben martinez peter j. stang baran group meeting...

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