research article mimicking peroxidase activity by a...

Research ArticleMimicking Peroxidase Activity by a Manganese(II)Complex Involving a New Asymmetric TetradentateLigand Containing Both Amino and Imino Groups

Yolanda Peacuterez-Otero M Isabel Fernaacutendez-Garciacutea Esther Goacutemez-FoacuterneasGustavo Gonzaacutelez-Riopedre and Marcelino Maneiro

Departamento de Quımica Inorganica Facultad de Ciencias Universidade de Santiago de Compostela 27002 Lugo Spain

Correspondence should be addressed to Marcelino Maneiro marcelinomaneirousces

Received 30 September 2015 Accepted 8 December 2015

Academic Editor Henryk Kozlowski

Copyright copy 2015 Yolanda Perez-Otero et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

The asymmetric ligand (E)-4-bromo-2-(((2-((5-bromo-2-hydroxybenzyl)(methyl)amino)ethyl)imino)methyl)phenol has beenprepared by a novel seven-step route All organic compounds isolated in each step have been characterised by elemental analysisinfrared and 1H NMR spectroscopy and mass spectrometry Interaction of this ligand with manganese has been investigatedemploying an electrochemical methodThis method leads to the formation of a neutral manganese(II) complex 7 in high yield andpurity The complex has been thoroughly characterised by elemental analysis infrared spectroscopy mass spectrometry magneticsusceptibility measurements and cyclic voltammetry Complex 7 behaves as peroxidase mimic in the presence of the water-solubletrap ABTS probably due to its ease to coordinate the substrate molecule

Dedicated to Professor Manuel R Bermejo on the occasion of his 70th birthday

1 Introduction

Oxidative stress causes uncontrolled oxidation of organicmolecules with secondary alteration of their structure andbiological functions leading to the progressive deteriorationand the collapse of organs and systems in the living organisms[1ndash3] The superoxide dismutase catalase and peroxidaseenzymes are part of the defense mechanisms against thereactive oxygen species generated by oxidative stress [4ndash7]

Vast interest has been developed to devise small moleculemodels the properties of which can be compared with dif-ferent metalloproteins [8ndash11] Biomimetic modeling of metalcomplexes has denoted a better catalytic behaviour when thecomplex is able to easily coordinate the substrate moleculeand this is favoured when the catalyst has either a vacancyin the coordination sphere or a labile ligand [12ndash15] Toachieve this a careful design of the ligand is necessary In this

connection unsymmetrical ligands are also required to imi-tate many of the active sites of the metalloproteins [16ndash18]

Tetradentate ONNO Schiff bases are well-known sys-tems for coordination of metal ions and their synthe-sis is easily accomplished by condensation of salicylalde-hyde and diamines [19 20] However this condensationfavours symmetrization processes and symmetric ligandsare systematically obtained even using a mixture of differentsalicylaldehydes in solution [21] Consequently alternativesynthetic routes should be explored to achieve unequivocallyunsymmetrical ligands

We report here on the synthesis of a new type of unsym-metrical ONNO tetradentate imino-amino bishydroxy ligandfollowing a novel seven-step synthetic route The ability ofthe new ligand to coordinate a redox-active metal ion asmanganese is checked by an electrochemical synthesis pro-cedure Finally catalytic studies to determine the peroxidase

Hindawi Publishing CorporationJournal of ChemistryVolume 2015 Article ID 963152 8 pageshttpdxdoiorg1011552015963152

2 Journal of Chemistry

activity have been carried out using the obtained manganesecompound

2 Materials and Methods

21 Materials All the starting materials (Aldrich) and sol-vents (Probus) used for the synthesis were of commerciallyavailable reagent grade and were used without further purifi-cation

22 Physical Measurements Elemental analyses were per-formed on a Carlo Erba Model 1108 CHNS-O elementalanalyser The IR spectra were recorded on KBr pellets ona Bio-Rad FTS 135 spectrophotometer in the range 4000ndash400 cmminus1 1H spectra were recorded on a Bruker AC-300 spectrometer using DMSO-d

6(296K) as solvent and

SiMe4as an internal reference FAB mass spectra were

recorded on a Kratos MS50TC spectrometer connected toa DS90 data system using meta-nitrobenzyl alcohol as amatrix Electrospray ionization mass spectra of the com-pounds were obtained on a Hewlett-Packard model LC-MSD 1100 instrument (positive-ion mode 98 2 CH

3OH

HCOOH as themobile phase 30ndash100V) Room-temperaturemagnetic susceptibilities were measured using a digitalmeasurement system MSB-MKI calibrated using mercurytetrakis(isothiocyanato)cobaltate(II) Hg[Co(NCS)

4] as a

susceptibility standard Magnetic data for 7 at differentapplied field strengths was obtained with a Quantum DesignPPMS susceptometer Conductivities of 10minus3M solutions inDMF were measured on a Crison microCM 2200 conduc-tivimeter

Cyclic voltammetry was performed using an EGampG PARmodel 273 potentiostat controlled by EGampG PAR model270 software A Metrohm model 61204000 graphite disccoupled to a Metrohm model 628-10 rotating electrolytedevice was used as a working electrode A saturated calomelelectrode was used as a reference and a platinum wire asan auxiliary electrode All measurements were made withca 10minus3mol dmminus3 solutions of the complexes in dimethylfor-mamide using 02mol dmminus3 NBu

4PF6as a supporting elec-

trode Cyclic voltammetry measurements were performedwith a static graphite electrode

23 Preparation of the Organic Ligand The asymmetricalligand (E)-4-bromo-2-(((2-((5-bromo-2-hydroxybenzyl)(meth-yl)amino)ethyl)imino)methyl)phenol (H2L1) has been suc-cessfully obtained by means of a seven-step synthetic route(see Scheme 1)

Phthalimido-acetal (1) Potassium phthalimide (5 g265mmol) bromoacetal (41mL 265mmol) and hexad-ecyltributylphosphonium bromide (138 g 265mmol) wereheated together in toluene (200mL) for 24 h at 111∘C underN2atmosphereThe product was then filtered and the filtrate

was concentrated on a rotary evaporator to give yellow oilColumn chromatography using hexane ether (1 1) allowedobtaining the desired compound Yield 70 Elementalanalysis calculated for C

14H17NO4(26329) C 638 H 64

N 53 found C 646 H 65 N 53 1H NMR (300MHzCDCl

3) 120575 78ndash76 (m 4H) 479 (t 1H) 375 (d 2H) 362ndash

342 (m 4H) 106 (t 6H) ES-MS 119898119911 264 IR ](C-O-C)2800 ](C=O) 1721 cmminus1

Phthalimidoacetaldehyde (2) The foregoing compound (3 g)and hydrochloric acid (15mL) were heated at 100∘C for 30minutes with stirring The product crystallised on coolingIt was collected and purified from diethyl ether Yield 80Elemental analysis calculated for C

10H7NO3(18917) C 634

H 37 N 74 found C 624 H 34 N 75 1H NMR (300MHzCDCl

3) 120575 962 (s 1H) 785ndash765 (m 4H) 445 (s 2H) ES-MS

119898119911 190 IR ](C=O) 1721 cmminus1

4-Bromo-2-((methylamino)methyl)phenol (3) To an ethano-lic solution (100mL) of 4-bromo-salicylaldehyde (5mL467mmol) methylamine (806mL 934mmol) was addedThemixture was heated under reflux in a round-bottom flaskfitted with a Dean-Stark trap to remove the water producedduring the reaction After heating for 3 h the solution isleft at room temperature and then sodium borohydride(090 g 233mmol) was added The solution was stirred for2 h before adding a second fraction of sodium borohydride(090 g 233mmol) After stirring for 2 h the solution wascooled in an ice bath and acidified to pH 2 The solventwas evaporated and the residue was extracted with distilledwaterdiethyl ether (3 times 20mL) The combined aqueousphases were adjusted to pH 11 by addition of aqueouspotassium hydroxide and extracted with dichloromethane(3 times 30mL) The combined organic phases were dried withanhydrous sodium sulphate and the solvent was evaporatedThe solid was dried in vacuo Yield 35 Elemental analysiscalculated for C

8H10BrNO (26329) C 444 H 46 N 65

found C 442 H 44 N 65 1H NMR (300MHz CDCl3) 120575

719ndash663 (m 3H) 48ndash42 (a 1H) 386 (s 2H) 240 (s 3H)ES-MS119898119911 264 IR ](O-H) 3014 ](N-H) 2736 cmminus1

2-((6-Bromo-3-methyl-34-dihydro-2H-benzo[e][13]oxazin-2-yl)methyl)isoindoline-13-dione (4) A 100mL Schlenkflask was charged under N

2with a solution of 072 g

(333mmol) of salicylamine 3 in THF Under N2stream

phthalimidoacetaldehyde 2 was added (095 g 503mmol)The flask saturated with N

2 is left to stir for 20 h at

room temperature Then a white product was collectedby filtration washed with diethyl ether and dried in airYield 65 Elemental analysis calculated for C

18H15BrN2O3

(38722) C 559 H 39 N 72 found C 550 H 42 N 74 1HNMR (300MHz CDCl

3) 120575 790-771 (m 4H) 726ndash664 (m

3H) 514 (t 1H) 408ndash395 (m 4H) 251 (s 3H) IR ](C=O)1719 cmminus1

2-(2-((5-Bromo-2-hydroxybenzyl)(methyl)amino)ethyl) isoin-doline-13-dione (5) Benzoxazine 4 (2 g 517mmol) wasstirred in amixture of dichloromethane (25mL) and acetoni-trile (20mL) Sodium cyanoborohydride (043 g 646mmol125 eq) was added and the mixture was acidified withhydrochloric acid to pH of ca 2 After 6 h the mix-ture was acidified with hydrochloric acid to pH ca 1After 1 h of stirring the solvent was removed The residue

Journal of Chemistry 3

was dried in vacuo and extracted with a 9 1 mixture ofdichloromethanemethanol (saturated with ammonia) Thesolvent was evaporated and the residue again vacuum-dried Recrystallization of the crude product from absolutemethanol afforded the desired product Yield 70 Elementalanalysis calculated for C

18H17BrNO

3(38924) C 555 H 44

N 72 found C 556 H 49 N 76 1H NMR (300MHzDMSO) 120575 789ndash780 (m 4H) 719 (d 2H) 649 (d 1H) 377(t 2H) 360 (s 2H) 270 (s 2H) 230 (s 3H) IR ](C=O)1709 cmminus1

2-(((2-Aminoethyl)(methyl)amino)methyl)-4-bromophenol(6) Under nitrogen a 100mL round-bottom flask wascharged with a solution of 031 g (079mmol) of 5 in 10mLof absolute tetrahydrofuran and 10mL of absolute ethanolHydrazine hydrate (99 026mL 5mmol) was added Afterstirring at room temperature for 24 h the reaction mixturewas acidified with concentrated hydrochloric acid to pHof ca 1 and stirred for another 10min The solvent wasevaporated and the residue was extracted with water (3 times20mL)The combined aqueous phases were adjusted to pH 11by addition of anhydrous potassium hydroxide and extractedwith dichloromethane (3 times 30mL) The combined organicphases were dried with anhydrous sodium sulphate and thesolvent was evaporated The solid residue was washed withdiethyl ether and then dried in vacuo Yield 45 Elementalanalysis calculated for C

10H15BrN2O (38924) C 463 H

58 N 108 found C 473 H 56 N 101 1H NMR (300MHzDMSO) 120575 721ndash662 (m 3H) 41ndash37 (a 2H) 359 (s 2H)284 (t 2H) 249 (t 2H) 223 (s 3H) ES-MS 119898119911 390 IR](O-H) 3473 ](N-H) 3280 cmminus1

(E)-4-Bromo-2-(((2-((5-bromo-2-hydroxybenzyl)(methyl)ami-no)ethyl)imino)methyl)phenol (H2L1) To a solution ofprimary amine 6 (0105 g 0405mmol) in chloroform4-bromo-salicylaldehyde (0081 g 0405mmol) was addedThemixture was heated under reflux in a round-bottom flaskfitted with a Dean-Stark trap to remove the water producedduring the reaction After heating for 3 h the solutionwas concentrated to yield a yellow solid The productwas collected by filtration washed with diethyl ether anddried in air Yield 85 Elemental analysis calculated forC17H18Br2N2O2(44214) C 461 H 41 N 63 found C 464

H 41 N 63 1H NMR (300MHz DMSO) 120575 812 (s 1H)734ndash660 (m 6H) 371 (t 2H) 365 (s 2H) 278 (t 2H)229 (s 3H) ES-MS119898119911 443 IR ](C=N) 1634 cmminus1 ](C-O)1270 cmminus1

24 Complex Preparation [MnL1(OH2)2]sdotH2O (7) wasobtained following an electrochemical procedure (seeFigure 1) The cell was a beaker (100 cm3) fitted with a rubberbung through which the electrochemical leads enteredthe cell [22] A manganese metal platelet was suspendedfrom a platinum wire and a platinum wire was used as acathode The ligandH2L1 (01 g) was dissolved in acetonitrile(70 cm3) and a small amount of tetramethylammoniumperchlorate was added as a supporting electrolyte Duringelectrolysis nitrogen was bubbled through the solution

G

O

M

P

T

Figure 1 Scheme of electrochemical cell T rubber stopper G inertgas entryexit P platinum cathode M manganese anode

to ensure the presence of an inert atmosphere with thecurrent being provided by a purpose built DC power supplyThe cells can be summarized as follows Pt(minus)MeCN +H2LnMn(+) During electrolysis hydrogen gas was evolvedat the cathode The solid was collected by filtration andwashed successively with acetonitrile and diethyl etherbefore drying in vacuo Yield 75 Elemental analysiscalculated for C

17H22MnBr

2N2O5(54911) C 372 H 40 N

51 found C 369 H 43 N 52 FAB 119898119911 4949 [MnL]+IR ](C=N) 1627 cmminus1 ](C-O) 1273 cmminus1 120583 = 594BM Conductivity (in DMF) Λ

119872= 9 120583S 119864ox = 0488V

119864red = 0150V 11986412 = 0319V

25 Peroxidase Probes Oxidation of 221015840-azinobis-(3-ethyl-benzothiazoline)-6-sulfonic acid (ABTS)withH

2O2at ca pH

68 in the presence of complex 7 was tested in the followingmanner An aqueous solution of ABTS (50120583L 0009M 45times 10minus7mol) and a methanolic solution of the complex (10120583L10minus3M 10minus8mol) were added to water (3mL) The intensityof the UV absorption bands of ABTS started to increaseimmediately after addition of an aqueous solution of H

2O2

(50 120583L 10M 5 times 10minus4mol)

3 Results and Discussion

Our synthetic sequence leading to the tetradentate ligandH2L1 is summarized in Scheme 1 All the precursors andorganic compoundswere characterised by elemental analysis1H NMR and IR spectroscopies and MS spectrometry

In the first step precursor 1was obtained throughGabrielsynthesis [23] The potassium salt of phthalimide was N-alkylated with a primary alkyl halide such as bromoacetalThe 1HNMRdoublet signal at 375 ppm corresponding to themethylene group next to the nitrogen atom (R1-N-CH2-R2)confirmed the formation of the phthalimido-acetal Figure 2shows the 1H NMR spectrum for 1 and for other organiccompounds of the synthetic route (2 4 and the final ligandH2L1)

Upon workup by acidic hydrolysis with aqueoushydrochloric acid phthalimidoacetaldehyde 2 was liberated


THF ethanol

+

+

+

Toluene N2Reflux 24h TLC

100∘C

30min

CH3NH2

NaBH4

N2

20h

NaBH3CN

CH2Cl2CH3CN

N2H4middotH2O NH2

CHCl3Reflux 3h

H3C(CH2)15P[(CH2)3CH3]3Br

2 + 3

N2 24h

Br O

O

NNK

O

O

O

O

O

ON

O

OH

O

OH

Br

O

H

OH

NHBr

O

NBr

N

O

O

OH

NBr

NO

O

OH

NBr

OH

Br O

H

OH

NN

HO Br

Br

1

HCl

2

Methanol

3

THF

4 5

5

6 H2L1

Scheme 1 Synthetic route to obtainH2L1

[24] A singlet signal in 1H NMR at 96 ppm was assigned tothe aldehyde proton (see Figure 2)

For the further course of the synthesis 4-bromo-sali-cylaldehyde reacted with methylamine in the presence of areducing agent such as sodium borohydride [25] This led toformation of primary amine 3 The salicylamine was identi-fied by the broad signal at about 48ndash42 ppm of the amineproton and also by the singlet at 38 ppm corresponding tothe protons of the methylene group

In a fourth step aminophenol 3 was condensed withphthalimidoacetaldehyde 2 affording benzoxazine 4 The1H NMR triplet at 51 ppm was characterised as the signalfrom the proton of the carbon between N and O atoms (seeFigure 2)The absence in 4 of the IR band at about 2600 cmminus1corresponding to the phenolic and aminic vibrational modes(showed in 2 and 3) also confirmed the progress of thereaction

Reductive cleavage of the acetalic C-O bond of 4 usingsodium cyanoborohydride gave N-phthaloyl-protected ethy-lene diamine 5 The benzoxacine signals disappeared inthe 1H NMR spectrum and the triplets at 38 ppm and27 ppm from themethylene chain formed [26] Deprotectionof 5 by hydrazinolysis proceeded smoothly showing thedisappearance of the phthalimide signals in 1H NMR and

the formation of a new broad signal at 41ndash37 ppm from theamine protons [27]

Primary amine 6 was finally condensed with 4-bromo-salicylaldehyde affording the Schiff baseH2L1 ((E)-4-bromo-2-(((2-((5-bromo-2-hydroxybenzyl)(methyl)amino)eth-yl)imino)methyl)phenol) The imine group from H2L1 isidentified by the singlet peak at 812 ppm (see 1H NMR inFigure 2) and also by the strong IR band at 1634 cmminus1 Other1H NMR signals elemental analysis and ES spectrometryconfirm the formation and purity of the H2L1 amine-imineligand

The reaction of H2L1 with a manganese plate inan electrochemical cell yields complex 7 with formula[MnL1(OH

2)2]sdotH2O [28] The electrochemical efficiency of

the cell around 05mol Fminus1 is in accordance with the follow-ing mechanism of the reaction

CathodeH2L + 2eminus 997888rarr H

2(g) + L2minus

Anode L2minus +Mn 997888rarr MnL + 2eminus(1)

This synthetic procedure allowed us to obtain the neutralcomplex with high purity and in very good yield Complex 7seems to be stable in air and thermally stable melting above


OH

NN

HO Br

Br

012345678910111213(ppm)

O

NBr

NO

O

012345678910111213

45678910

012345678910

N

O

O

O

O

N

O

O

O

H

1

2

4

a

a

a

a

a

b

b

c

c

d

d

ee

e

d

aa

aa

a

b b

cc

a

aaa ab

cd

b cd

e

fg

h

f

e g

h

a

b

c

d

e

e

a bc d e

f

f

gg

g

h

h

i

i

j

j

kk

H2L1

Figure 2 1H NMR spectra and assignments for 1 2 3 and the ligandH2L1


Table 1 Magnetic susceptibility and magnetic moment for 7 atdifferent applied field strengths

Field (G) 120594 (uemg) 120583 (B M)4696 03260 5835017 03373 5945251 03464 6195486 03555 6335718 03579 6405952 03637 651

300∘C without decomposition The complex is insoluble orsparingly soluble in water and common organic solvents butsoluble in polar coordinating solvents such as DMF DMSOand pyridine

The IR spectrum of 7 shows a strong band at 1627 cmminus1attributable to ](C=N) This band appears 7 cmminus1 shifted tolower frequency with respect to the free ligand Moreover](CminusO) band is also shifted 3 cmminus1 to higher frequency withrespect to the free ligand This behaviour is compatible withthe participation of both imine nitrogen and phenolic oxygenatoms in the coordination to the manganese ion illustratingthe dianionic and tetradentate character of this ligand in thecomplex [29]

The FAB mass spectra show a peak due to the fragment[MnL]+ which thus further corroborate coordination of theligand to the metal centre The conductivity value (9 120583S)suggests the nonionogenous nature for 7 [30]

Magnetic measurements were performed at room tem-perature for 7 with diamagnetic corrections The magneticmoment 120583 = 594 B M is close to those expected formagnetically dilute Mn(II) ions confirming the oxidationstate II for the central atom and therefore confirmingthe notion that the ligand acts as dianion The study ofthe magnetic behaviour at different applied field strengths(Table 1) confirms the values expected for magnetically diluteMn(II) ions Thus magnetic data suggest the presence ofmanganese(II) ion in an octahedral environment with littleor no interaction between neighbouring metal centres

Cyclic voltammogram of 7 was measured in dimethyl-formamide (DMF) over a potential range from +100 tominus100V In DMF solution the complex exhibits a quasi-reversible one-electron reduction-oxidation wave which atslow scan rates of about 002V sminus1 is reversible (Figure 3119864ox = 0488V 119864red = 0150V) Nevertheless the peak-to-peak separation (0338V) is slightly longer than in otherseries of manganese(II) complexes derived from tetradentateSchiff base ligands [12 13] highlighting a poorer reversiblecharacter for the present complex

31 Peroxidase Studies ABTS (diammonium salt of 22-azi-nobis-(3-ethylbenzothiazoline)-6-sulfonic acid) is a colour-less water-soluble compound used for clinical peroxidaseassays because of its excellent characteristics [31ndash33] Theperoxidase-like activity of 7 was followed by the oxidation ofthe ABTS at pH 68 ABTS is colourless and it reacts readily

minus04 minus02 00 02 04 06 08

minus20

minus10

00

10

20

E (V)

times105

I(A

)

Figure 3 Cyclic voltammogram for 7 at scan rate of 002V sminus1

400 500 600 700 80000

01

02

03

04

05

06

Abso

rban

ce

Wavelength (nm)

Figure 4 UV-Vis absorption spectrum of ABTS + H2O2+ 7

recorded 10min after mixing the solution

with hydrogen peroxide in the presence of a peroxidasecatalyst to yield a stable green coloured radical cation whichabsorbs light at 415 650 735 and 815 nm [34]

The reaction of ABTS with H2O2in the presence of 7

(complex concentration 33 10minus6M) generates ABTS∙+ Areduction of one mole of H

2O2requires two moles of ABTS

according to the mechanism

2ABTS +H2O2

Mn-SB Complex997888997888997888997888997888997888997888997888997888997888997888rarr 2ABTS∙+ + 2H

2O (2)

The oxidised form ABTS∙+ can be clearly identified byits characteristic absorption bands (Figure 4) and measuredquantitatively at 120582 = 650 nm since 120576 = 12000Mminus1 cmminus1has been determined Further oxidation to the correspondingdication was not observed In the absence of the complex asolution of ABTS andH

2O2is stable for several hours without

showing any formation of ABTS∙+The rate of formation of ABTS∙+ of about 11 shows a

significant capacity of hydrogen peroxide decomposition by7 The activity is comparable to that of a previous series ofMn-Schiff base complexes reported by us [12 13] but ismuch higher than an earlier Mn-Schiff base series with highsymmetrical octahedral geometries [35]


With regard to the peroxidase activity two of the mostimportant questions that are of concern are (a) the rate ofreversibility of the Mn(II)Mn(III) redox potentials and (b)the ease of coordination of the substrate molecule to themanganese ion The peak-to-peak separation of 0338V forthe oxidation-reduction wave of 7 is slightly longer than inother series of efficient peroxidase mimics and even longerthan in other series of Mn(II) inactive complexes Despitethis limited reversible character the behaviour of complex7 as peroxidase mimic may be attributable to its capacityto coordinate the substrate molecule Our strategy in thedesign of the ligand H2L1 sought adequate conformationsand flexibility to coordinate metal ions in a way that twoadjacent positions of the coordination sphere may be vacantor filled with labile ligandsThe different hybridization modefor the amino (sp3) and imino (sp2) groups may favourthe tetracoordination of the organic ligand outside from theequatorial plane of the metal ion In this case two of the cispositions of a hypothetical first coordination sphere wouldnot be occupied by the ligand and subsequently these twocis positions would be able to coordinate a suitable substratemolecule for catalysis

On the other hand the reversible character of the redoxpotentials for this new type of complexes may be increasedusing different electron donorwithdrawing substituents onthe phenyl rings of the ligand [36ndash38] Thus more efficientperoxidase mimics would be achieved using this new typeof asymmetric ligands containing both amino and iminogroups by employing appropriate substituents on the phenylrings

4 Conclusions

Complex 7 which behaves as a manganese(II) peroxidasemimic incorporates a new asymmetric ligandH2L1 contain-ing both amino and imino groups The seven-step syntheticroute for H2L1 afforded successfully the desired asymmetricproduct with a reasonable yield This synthetic strategy maybe used to obtain a new family of organic ligands suitablefor coordination of different metal ions The variety of thisnovel family of ligands may be envisioned by the chanceof replacing the methylamine used in the third step of thesynthetic route by different amines or amino acidsTheperox-idase activity of this type of complexes would be enhanced byemploying electron donorwithdrawing substituents on thephenyl rings to get complexes with better reversible characterfor the electrochemical processes

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

Financial support from the Xunta de Galicia (GRC2014025MetalBIO Network R2014004) is acknowledged

References

[1] B Halliwell and J M C Gutteridge Free Radicals in BiologyandMedicine OxfordUniversity PressOxfordUK 4th edition2007

[2] V Calabrese C Cornelius C Mancuso et al ldquoCellular stressresponse a novel target for chemoprevention and nutritionalneuroprotection in aging neurodegenerative disorders andlongevityrdquo Neurochemical Research vol 33 no 12 pp 2444ndash2471 2008

[3] MMMoschos E Nitoda I P Chatziralli andC ADemopou-los ldquoAge-related macular degeneration pathogenesis geneticbackground and the role of nutritional supplementsrdquo Journalof Chemistry vol 2014 Article ID 317536 9 pages 2014

[4] B Palenik B Brahamsha F W Larimer et al ldquoThe genome ofa motile marine Synechococcusrdquo Nature vol 424 no 6952 pp1037ndash1042 2003

[5] A J Wu J E Penner-Hahn and V L Pecoraro ldquoStructuralspectroscopic and reactivity models for the manganese cata-lasesrdquo Chemical Reviews vol 104 no 2 pp 903ndash938 2004

[6] S R Doctrow M Liesa S Melov O S Shirihai and P TofilonldquoSalen Mn complexes are superoxide dismutase and catalasemimetics that protect the mitocondriardquo Current InorganicChemistry vol 2 pp 325ndash334 2012

[7] N Gao H Li Q Li J Liu and G Luo ldquoSynthesis and kineticevaluation of a trifunctional enzymemimic with a dimanganeseactive centrerdquo Journal of Inorganic Biochemistry vol 105 no 2pp 283ndash288 2011

[8] T R Simmons G Berggren M Bacchi M Fontecave andV Artero ldquoMimicking hydrogenases from biomimetics toartificial enzymesrdquo Coordination Chemistry Reviews vol 270-271 pp 127ndash150 2014

[9] S Signorella and C Hureau ldquoBioinspired functional mimics ofthe manganese catalasesrdquo Coordination Chemistry Reviews vol256 no 11-12 pp 1229ndash1245 2012

[10] D Bani and A Bencini ldquoDeveloping ROS scavenging agentsfor pharmacological purposes recent advances in design ofmanganese-based complexes with anti-inflammatory and anti-nociceptive activityrdquo Current Medicinal Chemistry vol 19 no26 pp 4431ndash4444 2012

[11] I Batinic-Haberle J S Reboucas and I Spasojevic ldquoSuperoxidedismutase mimics chemistry pharmacology and therapeuticpotentialrdquo Antioxidants and Redox Signaling vol 13 no 6 pp877ndash918 2010

[12] M R Bermejo M I Fernandez A M Gonzalez-Noya etal ldquoNovel peroxidase mimics 120583-aqua manganese-Schiff basedimersrdquo Journal of Inorganic Biochemistry vol 100 pp 1470ndash1478 2006

[13] A Vazquez-Fernandez M R Bermejo M I Fernandez-Garcıa G Gonzalez-Riopedre M J Rodrıguez-Douton andM Maneiro ldquoInfluence of the geometry around the manganeseions on the peroxidase and the catalase activities of Mn(III)-Schiff base complexesrdquo Journal of Inorganic Biochemistry vol105 pp 1538ndash1547 2011

[14] G Gonzalez-Riopedre M I Fernandez-Garcıa A MGonzalez-Noya M A Vazquez-Fernandez M R BermejoandMManeiro ldquoManganese-Schiff base complexes as catalystsfor water photolysisrdquo Physical Chemistry Chemical Physics vol13 no 40 pp 18069ndash18077 2011

[15] G Gonzalez-Riopedre M R Bermejo M I Fernandez-Garcıaet al ldquoAlkali-metal-ion-directed self-assembly of redox-active


manganese(III) supramolecular boxesrdquo Inorganic Chemistryvol 54 no 6 pp 2512ndash2521 2015

[16] R Noyori and S Hashiguchi ldquoAsymmetric transfer hydrogena-tion catalyzed by chiral ruthenium complexesrdquo Accounts ofChemical Research vol 30 no 2 pp 97ndash102 1997

[17] Y Rondelez M-N Rager A Duprat and O ReinaudldquoCalix[6]arene-based cuprous lsquofunnel complexesrsquo a mimic forthe substrate access channel to metalloenzyme active sitesrdquoJournal of the American Chemical Society vol 124 no 7 pp1334ndash1340 2002

[18] G Zassinovich G Mestroni and S Gladiali ldquoAsymmetrichydrogen transfer reactions promoted by homogeneous transi-tion metal catalystsrdquo Chemical Reviews vol 92 no 5 pp 1051ndash1069 1992

[19] V Alexander ldquoDesign and synthesis of macrocyclic ligandsand their complexes of lanthanides and actinidesrdquo ChemicalReviews vol 95 no 2 pp 273ndash342 1995

[20] G Kumar R Johari and S Devi ldquoSynthesis physical charac-terization of M(III) transition metal complexes derived fromthiodihydrazide and 5-tert-butyl-2-hydroxy-3-(3-phenylpent-3-yl) benzaldehyderdquo E-Journal of Chemistry vol 9 no 4 pp2119ndash2127 2012

[21] E Lopez-Torres and M A Mendiola ldquoMercury complexeswith the ligand benzaldehyde-N(4)N(4)-dimethylthiosemicar-bazonerdquo Inorganica Chimica Acta vol 363 no 6 pp 1275ndash12832010

[22] R Pedrido M J Romero M R Bermejo et al ldquoInfluence ofthe metal size in the structure of the complexes derived from apentadentate [N

3O2] hydrazonerdquo Dalton Transactions no 44

pp 5304ndash5314 2006[23] J C Sheehan and W A Bolhofer ldquoAn improved procedure

for the condensation of potassium phthalimide with organichalidesrdquo Journal of the American Chemical Society vol 72 no6 pp 2786ndash2788 1950

[24] K Jarowicki and P Kocienski ldquoProtecting groupsrdquo Journal ofChemical Society Perkin Transactions vol 18 pp 2109ndash21352001

[25] J F Hartwig ldquoEvolution of a fourth generation catalyst for theamination and thioetherification of aryl halidesrdquo Accounts ofChemical Research vol 41 no 11 pp 1534ndash1544 2008

[26] A Berkessel M Bolte T Neumann and L Seidel ldquoSynthesisand X-ray crystal structure of the first mononuclear nickel(II)alkane thiolate complex with a mixed (SNNO) ligand fieldrdquoChemische Berichte vol 129 no 10 pp 1183ndash1189 1996

[27] M S Gibson and RW Bradshaw ldquoGabriel synthesis of primaryaminesrdquo Angewandte ChemiemdashInternational Edition vol 7 pp919ndash930 1968

[28] C Oldham and D G Tuck ldquoThe direct electrochemical syn-thesis of [(C

6H5)3Ph]2[CoCl

4] an example of the use of anodic

oxidation in the preparation of metal ion complexesrdquo Journal ofChemical Education vol 59 no 4 pp 420ndash421 1982

[29] R Golbedaghi S Salehzadeh H R Khavasi and A G Black-man ldquoMn(II) complexes of three [2 + 2] macrocyclic Schiffbase ligands Synthesis and X-ray crystal structure of the firstbinuclear-di(binuclear) cocrystalrdquo Polyhedron vol 68 pp 151ndash156 2014

[30] W J Geary ldquoThe use of conductivity measurements in organicsolvents for the characterisation of coordination compoundsrdquoCoordination Chemistry Reviews vol 7 no 1 pp 81ndash122 1971

[31] E S Ryabova P Rydberg M Kolberg et al ldquoA comparativereactivity study of microperoxidases based on hemin meso-hemin and deuteroheminrdquo Journal of Inorganic Biochemistryvol 99 no 3 pp 852ndash863 2005

[32] C L Hunter R Maurus M R Mauk et al ldquoIntroduction andcharacterization of a functionally linked metal ion binding siteat the exposed heme edge of myoglobinrdquo Proceedings of theNational Academy of Sciences of the United States of Americavol 100 no 7 pp 3647ndash3652 2003

[33] M Zampakou V Tangoulis C P Raptopoulou V PsycharisA N Papadopoulos and G Psomas ldquoStructurally diversemanganese(II)-diclofenac complexes showing enhancedantioxidant activity and affinity to serum albumins incomparison to sodium diclofenacordquo European Journal ofInorganic Chemistry vol 2015 no 13 pp 2285ndash2294 2015

[34] M F Zipplies W A Lee and T C Bruice ldquoInfluence ofhydrogen ion activity and general acid-base catalysis on the rateof decomposition of hydrogen peroxide by a novel nonaggre-gating water-soluble iron(III) tetraphenylporphyrin derivativerdquoJournal of the American Chemical Society vol 108 no 15 pp4433ndash4445 1986

[35] M Maneiro M R Bermejo A Sousa et al ldquoSynthe-sis and structural characterisation of new manganese(II)and (III) complexes Study of their photolytic and catalaseactivity and X-ray crystal structure of [Mn(3-OMe 5-Br-salpn)(EtOH)(H

2O)]ClO

4rdquo Polyhedron vol 19 no 1 pp 47ndash54

2000[36] K Mitra S Biswas C R Lucas and B Adhikary ldquoMan-

ganese(III) complexes of N2O2donor 5-bromosalicylidene-

imine ligands combined effects of electron withdrawing sub-stituents and chelate ring size variations on electrochemicalpropertiesrdquo Inorganica Chimica Acta vol 359 no 7 pp 1997ndash2003 2006

[37] S Naskar S Naskar R J Butcher M Corbella A EspinosaFerao and S K Chattopadhyay ldquoSynthesis X-ray crystalstructures and spectroscopic electrochemical and theoreticalstudies of MnIIIcomplexes of pyridoxal schiff bases with twodiaminesrdquo European Journal of Inorganic Chemistry no 18 pp3249ndash3260 2013

[38] C Palopoli C Duhayon J-P Tuchagues and S SignorellaldquoSynthesis characterization and reactivity studies of a water-soluble bis(alkoxo)(carboxylato)-bridged diMnIII complexmodeling the active site in catalaserdquo Dalton Transactions vol43 no 45 pp 17145ndash17155 2014

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


activity have been carried out using the obtained manganesecompound

2 Materials and Methods

21 Materials All the starting materials (Aldrich) and sol-vents (Probus) used for the synthesis were of commerciallyavailable reagent grade and were used without further purifi-cation

22 Physical Measurements Elemental analyses were per-formed on a Carlo Erba Model 1108 CHNS-O elementalanalyser The IR spectra were recorded on KBr pellets ona Bio-Rad FTS 135 spectrophotometer in the range 4000ndash400 cmminus1 1H spectra were recorded on a Bruker AC-300 spectrometer using DMSO-d

6(296K) as solvent and

SiMe4as an internal reference FAB mass spectra were

recorded on a Kratos MS50TC spectrometer connected toa DS90 data system using meta-nitrobenzyl alcohol as amatrix Electrospray ionization mass spectra of the com-pounds were obtained on a Hewlett-Packard model LC-MSD 1100 instrument (positive-ion mode 98 2 CH

3OH

HCOOH as themobile phase 30ndash100V) Room-temperaturemagnetic susceptibilities were measured using a digitalmeasurement system MSB-MKI calibrated using mercurytetrakis(isothiocyanato)cobaltate(II) Hg[Co(NCS)

4] as a

susceptibility standard Magnetic data for 7 at differentapplied field strengths was obtained with a Quantum DesignPPMS susceptometer Conductivities of 10minus3M solutions inDMF were measured on a Crison microCM 2200 conduc-tivimeter

Cyclic voltammetry was performed using an EGampG PARmodel 273 potentiostat controlled by EGampG PAR model270 software A Metrohm model 61204000 graphite disccoupled to a Metrohm model 628-10 rotating electrolytedevice was used as a working electrode A saturated calomelelectrode was used as a reference and a platinum wire asan auxiliary electrode All measurements were made withca 10minus3mol dmminus3 solutions of the complexes in dimethylfor-mamide using 02mol dmminus3 NBu

4PF6as a supporting elec-

trode Cyclic voltammetry measurements were performedwith a static graphite electrode

23 Preparation of the Organic Ligand The asymmetricalligand (E)-4-bromo-2-(((2-((5-bromo-2-hydroxybenzyl)(meth-yl)amino)ethyl)imino)methyl)phenol (H2L1) has been suc-cessfully obtained by means of a seven-step synthetic route(see Scheme 1)

Phthalimido-acetal (1) Potassium phthalimide (5 g265mmol) bromoacetal (41mL 265mmol) and hexad-ecyltributylphosphonium bromide (138 g 265mmol) wereheated together in toluene (200mL) for 24 h at 111∘C underN2atmosphereThe product was then filtered and the filtrate

was concentrated on a rotary evaporator to give yellow oilColumn chromatography using hexane ether (1 1) allowedobtaining the desired compound Yield 70 Elementalanalysis calculated for C

14H17NO4(26329) C 638 H 64

N 53 found C 646 H 65 N 53 1H NMR (300MHzCDCl

3) 120575 78ndash76 (m 4H) 479 (t 1H) 375 (d 2H) 362ndash

342 (m 4H) 106 (t 6H) ES-MS 119898119911 264 IR ](C-O-C)2800 ](C=O) 1721 cmminus1

Phthalimidoacetaldehyde (2) The foregoing compound (3 g)and hydrochloric acid (15mL) were heated at 100∘C for 30minutes with stirring The product crystallised on coolingIt was collected and purified from diethyl ether Yield 80Elemental analysis calculated for C

10H7NO3(18917) C 634

H 37 N 74 found C 624 H 34 N 75 1H NMR (300MHzCDCl

3) 120575 962 (s 1H) 785ndash765 (m 4H) 445 (s 2H) ES-MS

119898119911 190 IR ](C=O) 1721 cmminus1

4-Bromo-2-((methylamino)methyl)phenol (3) To an ethano-lic solution (100mL) of 4-bromo-salicylaldehyde (5mL467mmol) methylamine (806mL 934mmol) was addedThemixture was heated under reflux in a round-bottom flaskfitted with a Dean-Stark trap to remove the water producedduring the reaction After heating for 3 h the solution isleft at room temperature and then sodium borohydride(090 g 233mmol) was added The solution was stirred for2 h before adding a second fraction of sodium borohydride(090 g 233mmol) After stirring for 2 h the solution wascooled in an ice bath and acidified to pH 2 The solventwas evaporated and the residue was extracted with distilledwaterdiethyl ether (3 times 20mL) The combined aqueousphases were adjusted to pH 11 by addition of aqueouspotassium hydroxide and extracted with dichloromethane(3 times 30mL) The combined organic phases were dried withanhydrous sodium sulphate and the solvent was evaporatedThe solid was dried in vacuo Yield 35 Elemental analysiscalculated for C

8H10BrNO (26329) C 444 H 46 N 65

found C 442 H 44 N 65 1H NMR (300MHz CDCl3) 120575

719ndash663 (m 3H) 48ndash42 (a 1H) 386 (s 2H) 240 (s 3H)ES-MS119898119911 264 IR ](O-H) 3014 ](N-H) 2736 cmminus1

2-((6-Bromo-3-methyl-34-dihydro-2H-benzo[e][13]oxazin-2-yl)methyl)isoindoline-13-dione (4) A 100mL Schlenkflask was charged under N

2with a solution of 072 g

(333mmol) of salicylamine 3 in THF Under N2stream

phthalimidoacetaldehyde 2 was added (095 g 503mmol)The flask saturated with N

2 is left to stir for 20 h at

room temperature Then a white product was collectedby filtration washed with diethyl ether and dried in airYield 65 Elemental analysis calculated for C

18H15BrN2O3

(38722) C 559 H 39 N 72 found C 550 H 42 N 74 1HNMR (300MHz CDCl

3) 120575 790-771 (m 4H) 726ndash664 (m

3H) 514 (t 1H) 408ndash395 (m 4H) 251 (s 3H) IR ](C=O)1719 cmminus1

2-(2-((5-Bromo-2-hydroxybenzyl)(methyl)amino)ethyl) isoin-doline-13-dione (5) Benzoxazine 4 (2 g 517mmol) wasstirred in amixture of dichloromethane (25mL) and acetoni-trile (20mL) Sodium cyanoborohydride (043 g 646mmol125 eq) was added and the mixture was acidified withhydrochloric acid to pH of ca 2 After 6 h the mix-ture was acidified with hydrochloric acid to pH ca 1After 1 h of stirring the solvent was removed The residue



18H17BrNO

3(38924) C 555 H 44



10H15BrN2O (38924) C 463 H





G

O

M

P

T



17H22MnBr

2N2O5(54911) C 372 H 40 N


119872= 9 120583S 119864ox = 0488V

119864red = 0150V 11986412 = 0319V


2O2at ca pH


2O2







THF ethanol

+

+

+


100∘C

30min

CH3NH2

NaBH4

N2

20h

NaBH3CN

CH2Cl2CH3CN

N2H4middotH2O NH2

CHCl3Reflux 3h


2 + 3

N2 24h

Br O

O

NNK

O

O

O

O

O

ON

O

OH

O

OH

Br

O

H

OH

NHBr

O

NBr

N

O

O

OH

NBr

NO

O

OH

NBr

OH

Br O

H

OH

NN

HO Br

Br

1

HCl

2

Methanol

3

THF

4 5

5

6 H2L1












2(g) + L2minus




OH

NN

HO Br

Br

012345678910111213(ppm)

O

NBr

NO

O

012345678910111213

45678910

012345678910

N

O

O

O

O

N

O

O

O

H

1

2

4

a

a

a

a

a

b

b

c

c

d

d

ee

e

d

aa

aa

a

b b

cc

a

aaa ab

cd

b cd

e

fg

h

f

e g

h

a

b

c

d

e

e

a bc d e

f

f

gg

g

h

h

i

i

j

j

kk

H2L1




Field (G) 120594 (uemg) 120583 (B M)4696 03260 5835017 03373 5945251 03464 6195486 03555 6335718 03579 6405952 03637 651







minus04 minus02 00 02 04 06 08

minus20

minus10

00

10

20

E (V)

times105

I(A

)


400 500 600 700 80000

01

02

03

04

05

06

Abso

rban

ce

Wavelength (nm)








2ABTS +H2O2


2O (2)








4 Conclusions




Acknowledgment


References

































6H5)3Ph]2[CoCl










2O)]ClO
















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



18H17BrNO

3(38924) C 555 H 44



10H15BrN2O (38924) C 463 H





G

O

M

P

T



17H22MnBr

2N2O5(54911) C 372 H 40 N


119872= 9 120583S 119864ox = 0488V

119864red = 0150V 11986412 = 0319V


2O2at ca pH


2O2







THF ethanol

+

+

+


100∘C

30min

CH3NH2

NaBH4

N2

20h

NaBH3CN

CH2Cl2CH3CN

N2H4middotH2O NH2

CHCl3Reflux 3h


2 + 3

N2 24h

Br O

O

NNK

O

O

O

O

O

ON

O

OH

O

OH

Br

O

H

OH

NHBr

O

NBr

N

O

O

OH

NBr

NO

O

OH

NBr

OH

Br O

H

OH

NN

HO Br

Br

1

HCl

2

Methanol

3

THF

4 5

5

6 H2L1












2(g) + L2minus




OH

NN

HO Br

Br

012345678910111213(ppm)

O

NBr

NO

O

012345678910111213

45678910

012345678910

N

O

O

O

O

N

O

O

O

H

1

2

4

a

a

a

a

a

b

b

c

c

d

d

ee

e

d

aa

aa

a

b b

cc

a

aaa ab

cd

b cd

e

fg

h

f

e g

h

a

b

c

d

e

e

a bc d e

f

f

gg

g

h

h

i

i

j

j

kk

H2L1




Field (G) 120594 (uemg) 120583 (B M)4696 03260 5835017 03373 5945251 03464 6195486 03555 6335718 03579 6405952 03637 651







minus04 minus02 00 02 04 06 08

minus20

minus10

00

10

20

E (V)

times105

I(A

)


400 500 600 700 80000

01

02

03

04

05

06

Abso

rban

ce

Wavelength (nm)








2ABTS +H2O2


2O (2)








4 Conclusions




Acknowledgment


References

































6H5)3Ph]2[CoCl










2O)]ClO
















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


THF ethanol

+

+

+


100∘C

30min

CH3NH2

NaBH4

N2

20h

NaBH3CN

CH2Cl2CH3CN

N2H4middotH2O NH2

CHCl3Reflux 3h


2 + 3

N2 24h

Br O

O

NNK

O

O

O

O

O

ON

O

OH

O

OH

Br

O

H

OH

NHBr

O

NBr

N

O

O

OH

NBr

NO

O

OH

NBr

OH

Br O

H

OH

NN

HO Br

Br

1

HCl

2

Methanol

3

THF

4 5

5

6 H2L1












2(g) + L2minus




OH

NN

HO Br

Br

012345678910111213(ppm)

O

NBr

NO

O

012345678910111213

45678910

012345678910

N

O

O

O

O

N

O

O

O

H

1

2

4

a

a

a

a

a

b

b

c

c

d

d

ee

e

d

aa

aa

a

b b

cc

a

aaa ab

cd

b cd

e

fg

h

f

e g

h

a

b

c

d

e

e

a bc d e

f

f

gg

g

h

h

i

i

j

j

kk

H2L1




Field (G) 120594 (uemg) 120583 (B M)4696 03260 5835017 03373 5945251 03464 6195486 03555 6335718 03579 6405952 03637 651







minus04 minus02 00 02 04 06 08

minus20

minus10

00

10

20

E (V)

times105

I(A

)


400 500 600 700 80000

01

02

03

04

05

06

Abso

rban

ce

Wavelength (nm)








2ABTS +H2O2


2O (2)








4 Conclusions




Acknowledgment


References

































6H5)3Ph]2[CoCl










2O)]ClO
















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


OH

NN

HO Br

Br

012345678910111213(ppm)

O

NBr

NO

O

012345678910111213

45678910

012345678910

N

O

O

O

O

N

O

O

O

H

1

2

4

a

a

a

a

a

b

b

c

c

d

d

ee

e

d

aa

aa

a

b b

cc

a

aaa ab

cd

b cd

e

fg

h

f

e g

h

a

b

c

d

e

e

a bc d e

f

f

gg

g

h

h

i

i

j

j

kk

H2L1




Field (G) 120594 (uemg) 120583 (B M)4696 03260 5835017 03373 5945251 03464 6195486 03555 6335718 03579 6405952 03637 651







minus04 minus02 00 02 04 06 08

minus20

minus10

00

10

20

E (V)

times105

I(A

)


400 500 600 700 80000

01

02

03

04

05

06

Abso

rban

ce

Wavelength (nm)








2ABTS +H2O2


2O (2)








4 Conclusions




Acknowledgment


References

































6H5)3Ph]2[CoCl










2O)]ClO
















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



Field (G) 120594 (uemg) 120583 (B M)4696 03260 5835017 03373 5945251 03464 6195486 03555 6335718 03579 6405952 03637 651







minus04 minus02 00 02 04 06 08

minus20

minus10

00

10

20

E (V)

times105

I(A

)


400 500 600 700 80000

01

02

03

04

05

06

Abso

rban

ce

Wavelength (nm)








2ABTS +H2O2


2O (2)








4 Conclusions




Acknowledgment


References

































6H5)3Ph]2[CoCl










2O)]ClO
















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




4 Conclusions




Acknowledgment


References

































6H5)3Ph]2[CoCl










2O)]ClO
















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


















6H5)3Ph]2[CoCl










2O)]ClO
















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

research article mimicking peroxidase activity by a...

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