New unsymmetric dinuclear CuIICuII complexes and their relevance to copper(II) containing metalloenzymes and DNA cleavage

Peralta, Rosely A.; Neves, Ademir; Bortoluzzi, Adaı́lton J.; Anjos, Ademir dos; Xavier, Fernando R.; Szpoganicz, Bruno; Terenzi, Hernán; Oliveira, Maurício César Bof de; Castellano, Eduardo E.; Friedermann, Geraldo R.; Mangrich, Antônio S.; Novak, Miguel A.

doi:10.1016/j.jinorgbio.2006.01.041

Cited by 54 publications

(38 citation statements)

References 45 publications

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“…The TON value observed in the present case is well within the range observed by a number of mono-and dinuclear copper complexes reported in the literature [8][9][10][11][12][13][14][15][16][17][18][19].…”

supporting

confidence: 90%

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Coordination characteristics of di-O-picolyl derivative of 1,1′-methylene-bis(2-naphthol): First crystal structure of a monomeric Cu(II) complex of bis{2-[(pyridin-2-yl)methoxy] naphthalen-1-yl}methane

Baghel

Mobin

Rao

2009

Inorganica Chimica Acta

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supporting

confidence: 90%

“…C, H and N analysis were performed on a Carlo Erba 1106 elemental analyzer and that of the copper content was estimated using ICP-AES. The 1 H and 13 C NMR spectra were recorded on a Varian 400S spectrometer in CDCl 3 or DMSO-d 6 . UVVis spectra were obtained on a Shimadzu UV-260 or UV-2101PC spectrophotometer.…”

Section: Generalmentioning

confidence: 99%

Coordination characteristics of di-O-picolyl derivative of 1,1′-methylene-bis(2-naphthol): First crystal structure of a monomeric Cu(II) complex of bis{2-[(pyridin-2-yl)methoxy] naphthalen-1-yl}methane

Baghel

Mobin

Rao

2009

Inorganica Chimica Acta

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“…observed from Cu 4 L 4 is comparable to those with moderate to high catecholase activities. [8][9][10][11][12][13][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] It is noticeable that the four copper ions are non-coupled in Cu 4 L 4 whereas most model complexes with high catecholase activities are di-or tri-nuclear copper …”

Section: Resultsmentioning

confidence: 99%

Tetrameric Self-Assembly of a Cu(II) Complex Containing Schiff-Base Ligand and Its Unusually High Catecholase-like Activity

Sarkar¹,

Lee²,

Hong³

et al. 2013

Bulletin of the Korean Chemical Society

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We report a new tetrameric supramolecular Cu(II) complex (Cu 4 L 4 = tetrakis(N,N'-bis(salicylidene)-2,2'-ethylenedianiline)Copper(II)) with a Schiff-base ligand (H 2 L = N,N'-bis (salicylaldimine)-1,2-ethylenediamine) containing two N,O-bidentate chelate groups. Though the copper sites of Cu 4 L 4 are non-coupled, the complex exhibits a unsually high catecholase-like activity (k cat = 935 h −1 ) when the Cu 4 L 4 solution is treated with 3,5-di-tert-butylcatechol (3,5-DTBC) at basic condition in the presence of air. Combined information obtained from UV-VIS and EPR measurements could lead the suggestion of the reaction pathway in which the substrate may bind to Cu(II) ions by anti-anti didentate bridging mode.

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“…The initial rate at each substrate concentration was obtained by fitting a second degree polynomial to the absorbance vs. time plot, 34 using e(400 nm) = 1900 mol L -1 cm -1 for 3,5-di-tertbutylquinone. 35 A Michaelis-Menten approach was applied using a non-linear fit to obtain V max and K M parameters. …”

Section: Reactivity Cyclohexane Oxidationmentioning

confidence: 99%

“…The values for complexes 1 and 2 indicate that they are very efficient compared to other complexes in the literature. 35,64,65 The kinetic efficiency (k cat /K M ) shows that complex 2 is approximately 10 times more active than complex 1. Usually, the catecholase activity of model complexes is largely attributed to the distance Cu … Cu, but other effects such as redox potentials, neighboring groups, and the individual coordination spheres can play important roles.…”

Section: Catechol Oxidationmentioning

confidence: 99%

Binuclear CuII complexes as catalysts for hydrocarbon and catechol oxidation reactions with hydrogen peroxide and molecular oxygen

Martins¹,

Souza²,

Fernandez³

et al. 2010

J. Braz. Chem. Soc.

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Dois ligantes tridentados, HL1, [(2-hidroxibenzil)(2-(imidazol-2-il)etil)]amina, e HL2, [(2-hidroxibenzil)(2-(piridil-2-il)etil]amina, foram usados na síntese dos complexos binucleares [Cu 2 (L1) 2 ]Cl 2• 2H 2 O, complexo 1, e [Cu 2 (L2) 2 ] (ClO 4 ) 2• 1.5H 2 O, complexo 2, para serem empregados como catalisadores em processos de oxidação. Os complexos foram caracterizados por análise elementar e espectroscopias na região do infravermelho, ultravioleta-visível e ressonância paramagnética eletrônica. Foram também estudados por voltametria cíclica e titulação potenciométrica, a fim de caracterizar seus comportamentos em solução. A resolução da estrutura cristalina do complexo 1 mostrou um cátion binuclear contendo dois grupos fenóxido em ponte. Este arranjo possui uma distância Cu … Cu de 3.043(10) Å, similar à observada na catecol oxidase (2.90 Å). Os comportamentos catalíticos destes complexos foram investigados nas oxidações de cicloexano e de catecol. Na oxidação de cicloexano observou-se baixa atividade para ambos os complexos, que pode ser atribuída ao estereoimpedimento produzido pela falta de coplanaridade entre os anéis aromáticos do arcabouço dos ligantes, sugerindo que a aproximação entre o substrato e o centro ativo binuclear é uma etapa determinante no mecanismo da reação. Com relação à atividade de catecolase, foram observadas altas eficiências, com o complexo 2 sendo mais ativo que o complexo 1. Isto indica que o ligante piridina é capaz de estabilizar melhor o intermediário proposto para esse processo, que contém o centro Cu • 1.5H 2 O, complex 2, in order to obtain catalysts for oxidative processes. Both complexes were characterized by elemental analysis, IR, UV-Vis and EPR spectroscopies. In addition, they were studied by cyclic voltammetry and potentiometric titration in order to investigate their behavior in solution. The crystal structure of complex 1 revealed a binuclear cation where the metal centers are bridged by two phenoxo groups. This arrangement provides a Cu … Cu distance of 3.043(10) Å, which is similar to the observed for catechol oxidase (2.90 Å). The catalytic reactivities of both complexes were investigated for hydrocarbon and catechol oxidations. Complexes 1 and 2 led to low overall hydrocarbon oxidation conversion values of 6.34 % and 7.15 %, respectively. However, for complex 1, only cyclohexanol (Cy-OH) and cyclohexanone (Cy=O) were isolated as reaction products, with selectivities of 68.1% for Cy-OH. This low overall conversion is tentatively attributed to steric hindrance effects produced by the non-coplanar aromatic rings of the ligand scaffolds, which suggest that the access of the hydrocarbon molecule to the binuclear active center is a determinant step in the reaction mechanism. Investigation of catecholase activities has shown high efficiencies, with complex 2 being more active than complex 1. It indicates that the pyridine-containing ligand is able to stabilize the intermediate Cu I Cu I center which is proposed to be formed in this process. This is corroborated by t...

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New unsymmetric dinuclear CuIICuII complexes and their relevance to copper(II) containing metalloenzymes and DNA cleavage

Cited by 54 publications

References 45 publications

Coordination characteristics of di-O-picolyl derivative of 1,1′-methylene-bis(2-naphthol): First crystal structure of a monomeric Cu(II) complex of bis{2-[(pyridin-2-yl)methoxy] naphthalen-1-yl}methane

Coordination characteristics of di-O-picolyl derivative of 1,1′-methylene-bis(2-naphthol): First crystal structure of a monomeric Cu(II) complex of bis{2-[(pyridin-2-yl)methoxy] naphthalen-1-yl}methane

Tetrameric Self-Assembly of a Cu(II) Complex Containing Schiff-Base Ligand and Its Unusually High Catecholase-like Activity

Binuclear CuII complexes as catalysts for hydrocarbon and catechol oxidation reactions with hydrogen peroxide and molecular oxygen

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