Oxidation of 3,5-ditert-butylcatechol catalyzed by copper(II) complexes. A kinetic study

Manzur, Jorge; García, Ana María; Rivas, Vanessa; Atria, Ana Marı́a; Valenzuela, Jorge; Spodine, Evgenia

doi:10.1016/s0277-5387(96)00528-1

Cited by 34 publications

(15 citation statements)

References 21 publications

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“…3,5-DTBC-H 2 is well suited for catechol oxidase studies [43,44] due to its stability, low redox potential [45][46][47][48] and the presence of bulky functional groups precluding further reactions. Consequently, it has been used in many model studies of CO as a substrate [49][50][51][52][53][54][55].…”

Section: Catechol Oxidase Activitymentioning

confidence: 99%

Tyrosinase and catechol oxidase activity of copper(I) complexes supported by imidazole-based ligands: structure–reactivity correlations

2016

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Four new imidazole-based ligands, 4-((1H-imidazol-4-yl)methyl)-2-phenyl-4,5-dihydrooxyzole (L OL 1), 4-((1H-imidazol-4-yl)methyl)-2-(tert-butyl)-4,5-dihydrooxyzole (L OL 2), 4-((1H-imidazol-4-yl)methyl)-2-methyl-4,5-dihydrooxyzole (L OL 3), and N-(2,2-dimethylpropylidene)-2-(1-trityl-1H-imidazol-4-yl-)ethyl amine (L imz 1), have been synthesized. The corresponding copper(I) complexes [Cu(I)(L OL 1)(CH3CN)]PF6 (CuL OL 1), [Cu(I)(L OL 2)(CH3CN)]PF6 (CuL OL 2), [Cu(I)(L OL 3)(CH3CN)]PF6 (CuL OL 3), [Cu(I)(L imz 1)(CH3CN)2]PF6 (CuL imz 1) as well as the Cu(I) complex derived from the known ligand bis(1-methylimidazol-2-yl)methane (BIMZ), [Cu(I)(BIMZ)(CH3CN)]PF6 (CuBIMZ), are screened as catalysts for the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC-H2) to 3,5-di-tert-butylquinone (3,5-DTBQ). The primary reaction product of these oxidations is 3,5-di-tert-butylsemiquinone (3,5-DTBSQ) which slowly converts to 3,5-DTBQ. Saturation kinetic studies reveal a trend of catalytic activity in the order CuL OL 3 ≈ CuL OL 1 > CuBIMZ > CuL OL 2 > CuL imz 1. Additionally, the catalytic activity of the copper(I) complexes towards the oxygenation of monophenols is investigated. As substrates 2,4-di-tert-butylphenol (2,4-DTBP-H), 3-tert-butylphenol (3-TBP-H), 4-methoxyphenol (4-MeOP-H), N-acetyl-L-tyrosine ethyl ester monohydrate (NATEE) and 8-hydroxyquinoline are employed. The oxygenation products are identified and characterized with the help of UV/Vis and NMR spectroscopy, mass spectrometry, and fluorescence measurements. Whereas the copper complexes with ligands containing combinations of imidazole and imine functions or two imidazole units (CuL imz 1 and CuBIMZ) are found to exhibit catalytic tyrosinase activity, the systems with ligands containing oxazoline just mediate a stoichiometric conversion. Correlations between the structures of the complexes and their reactivities are discussed.

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Section: Catechol Oxidase Activitymentioning

confidence: 99%

Tyrosinase and catechol oxidase activity of copper(I) complexes supported by imidazole-based ligands: structure–reactivity correlations

2016

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“…The catalytic oxidation of 3,5-di-tert-butylcatechol has been studied as a model reaction for the catecholase activity of tyrosinase and catechol oxidase [5][6][7][8] . The kinetic studies on the oxidation of 3,5-DtBC were carried out by the method of initial rates by monitoring the increase in the characteristic quinone (3,5-DtBQ) absorption band at 400 nm as a function of time.…”

Section: Kinetic Studies For Catecholase Activitymentioning

confidence: 99%

“…In order to investigate the ability of this complex to catalyze the oxidation of catechol to oquinone (catecholase activity) we employed 3,5-di-tertbutylcatechol (3,. Owing to the great interest in catecholase activity investigations, many copper complexes have been tested with regard to this substrate [5][6][7][8] .…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Structure, Physicochemical Properties and Catecholase-like Activity of a New Dicopper(II) Complex

Neves¹,

Rossi²,

Bortoluzzi³

et al. 2001

J. Braz. Chem. Soc.

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Neste trabalho, reportamos a síntese, caracterização e atividade de catecolase do complexo binuclear de cobre [Cu 2 (H 2 bbppnol)(µ-OAc)(µ-ClO 4)] ClO 4 •H 2 O•EtOAc contendo o ligante N,N'-2-hidroxibenzil-N,N'-2-piridilmetil-2-hidroxipropano-1,3-diamina (H 3 bbppnol). O complexo foi caracterizado através de espectroscopias no infravermelho e eletrônica, ressonância paramagnética eletrônica, medidas de susceptibilidade magnética e cristalografia de raios-X. A atividade de catecolase do complexo foi determinada espectrofotometricamente, monitorando-se a oxidação do substrato 3,5-di-terc-butilcatecol à correspondente o-benzoquinona, em solução de metanol saturada com O 2 /tampão aquoso (pH 8), a 25 o C. O complexo mostrou-se capaz de oxidar o substrato modelo com uma constante catalítica de 0,0057 s-1. The synthesis, characterization and catecholase activity studies of the complex [Cu 2 (H 2 bbppnol)(µ-OAc)(µ-ClO 4)]ClO 4 •H 2 O•EtOAc containing the dinucleating ligand N,N'-2-hydroxybenzyl-N,N'-2-pyridylmethyl-2-hydroxypropane-1,3-diamine (H 3 bbppnol) are presented here. The complex was characterized by IR, electronic and EPR spectroscopies, cyclic voltammetry, magnetic susceptibility measurements and X-ray crystallography. The catecholaselike activity of the complex was determined spectrophotometrically by monitoring the oxidation of 3,5-di-tert-butylcatechol to the corresponding o-benzoquinone in O 2-saturated methanol/aqueous buffer (pH 8) mixtures at 25ºC. The complex was able to oxidize the model substrate with a turnover number of 0.0057 s-1 .

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“…The catecholase-like active model binuclear copper(II) complexes with different structural parameters have been investigated. [11][12][13][14][15][16][17][18][19][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] Krebs and co-worker 27,28 re-ported structural correlations of catecholase activity in phenoxy-and alkoxo-bridged dinuclear Cu(II) complexes. Recently, detailed mechanistic and electrochemical 29,30 and pH-dependent 17,31,32 investigations on the catecholase activity of model dinuclear copper complexes have been reported.…”

Section: Introductionmentioning

confidence: 99%

Crystal Structures, Magnetic Properties and Catecholase‐Like Activities of μ‐Alkoxo‐μ‐Carboxylato Double Bridged Dinuclear and Tetranuclear Copper(II) Complexes

Chen

Lü

Wei

2009

J Chinese Chemical Soc

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One μ‐alkoxo‐μ‐carboxylato bridged dinuclear copper(II) complex, [Cu2(L1)(μ‐C6H5CO2)] (1)(H3L1 = 1,3‐bis(salicylideneamino)‐2‐propanol)), and two μ‐alkoxo‐μ‐dicarboxylato doubly‐bridged tetranuclear copper(II) complexes, [Cu4(L1)2(μ‐C8H10O4)(DMF)2]·H2O (2) and [Cu4(L2)2(μ‐C5H6O4]·2H2O·2CH3CN (3) (H3L2 = 1,3‐bis(5‐bromo‐salicylideneamino)‐2‐propanol)) have been prepared and characterized. The single crystal X‐ray analysis shows that the structure of complex 1 is dimeric with two adjacent copper(II) atoms bridged by μ‐alkoxo‐μ‐carboxylato ligands where the Cu···Cu distances and Cu‐O(alkoxo)‐Cu angles are 3.5 11 Å and 132.8°, respectively. Complexes 2 and 3 consist of a μ‐alkoxo‐μ‐dicarboxylato doubly‐bridged tetranuclear Cu(II) complex with mean Cu‐Cu distances and Cu‐O‐Cu angles of 3.092 Å and 104.2° for 2 and 3.486 Å and 129.9° for 3, respectively. Magnetic measurements reveal that 1 is strong antiferromagnetically coupled with 2J =‐210 cm−1 while 2 and 3 exhibit ferromagnetic coupling with 2J = 126 cm−1 and 82 cm−1 (averaged), respectively. The 2J values of 1–3 are correlated to dihedral angles and the Cu‐O‐Cu angles. Dependence of the pH at 25 °C on the reaction rate of oxidation of 3,5‐di‐tert‐butylcatechol (3,5‐DTBC) to the corresponding quinone (3,5‐DTBQ) catalyzed by 1–3 was studied. Complexes 1–3 exhibit catecholase‐like active at above pH 8 and 25 °C for oxidation of 3,5‐di‐tert‐butylcatechol.

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Oxidation of 3,5-ditert-butylcatechol catalyzed by copper(II) complexes. A kinetic study

Cited by 34 publications

References 21 publications

Tyrosinase and catechol oxidase activity of copper(I) complexes supported by imidazole-based ligands: structure–reactivity correlations

Tyrosinase and catechol oxidase activity of copper(I) complexes supported by imidazole-based ligands: structure–reactivity correlations

Synthesis, Structure, Physicochemical Properties and Catecholase-like Activity of a New Dicopper(II) Complex

Crystal Structures, Magnetic Properties and Catecholase‐Like Activities of μ‐Alkoxo‐μ‐Carboxylato Double Bridged Dinuclear and Tetranuclear Copper(II) Complexes

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