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Functional mimics of catechol oxidase by mononuclear copper complexes of sterically demanding [NNO] ligands

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Title Functional mimics of catechol oxidase by mononuclear copper complexes of sterically demanding [NNO] ligands
 
Creator PANDA, MK
SHAIKH, MM
BUTCHER, RJ
GHOSH, P
 
Subject PURPLE ACID-PHOSPHATASES
SCHIFF-BASE LIGANDS
IRON(III) COMPLEXES
CRYSTAL-STRUCTURE
DICOPPER(II) COMPLEXES
MODELS
OXIDATION
DIOXYGEN
PROTEINS
DENSITY
Copper
Catechol oxidase
Oxidation
Density functional theory
Catalysis
 
Description Several mononuclear copper complexes 1(a-b) and 2(a-b) supported over sterically demanding [NNO] ligands namely, N-(aryl)-2-[(pyridin-2-ylmethyl) amino] acetamide [aryl = 2,6-diethylphenyl (1) and mesityl (2)], exhibit catecholase-like activity in performing the aerial oxidation of 3,5-di-t-butylcatehol (3,5-DTBC) to 3,5-di-t-butyl-catequinone (3,5-DTBQ) under ambient conditions. The 1(a-b) and 2(a-b) complexes were directly synthesized from the reaction of the respective ligands 1-2 with CuX(2)center dot nH(2)O (X = Cl, NO(3), n = 2, 3) in 55-85% yield. Mechanistic insights on the catalytic cycle as obtained by density functional theory studies for a representative complex 1a suggest that an intramolecular hydrogen transfer, from a catechol-OH moiety to a copper bound superoxo moiety, form the rate-determining step of the oxidation process, displaying an activation barrier of 18.3 kcal/mol (Delta G(double dagger)) [6.9 kcal/mol in Delta(PE + ZPE)(double dagger) scale]. (C) 2011 Elsevier B. V. All rights reserved.
 
Publisher ELSEVIER SCIENCE SA
 
Date 2012-06-26T06:47:24Z
2012-06-26T06:47:24Z
2011
 
Type Article
 
Identifier INORGANICA CHIMICA ACTA,372(1)145-151
0020-1693
http://dx.doi.org/10.1016/j.ica.2011.01.081
http://dspace.library.iitb.ac.in/jspui/handle/100/14075
 
Language English