An angular trinuclear copper(II) complex as a model for the active site of multicopper oxidases

Gupta, Sunita and Mukherjee, Arindam and Nethaji, Munirathinam and Chakravarty, Akhil R (2004) An angular trinuclear copper(II) complex as a model for the active site of multicopper oxidases. In: Polyhedron, 23 (4). pp. 643-647.

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Abstract

A new angular trinuclear copper(II) complex $[Cu_3L^1L^2(1-MeIm)(H_2O)](ClO_4) (1),$ where $H_3L^1$ and $H_2L^2$ are penta and tetradentate Schi. base ligands, is prepared from a reaction of $[CuL^2]$ and $[Cu_2L^1(\mu-Br)]$ in the presence of 1-methylimidazole (1-MeIm) and isolated as a perchlorate salt. The complex which crystallizes in the monoclinic space group $P2_1/n$ shows the presence of a discrete angular trinuclear copper(II) core in which the monomeric precursor is linked with the dimeric precursor through phenoxo bridges. The core structure resembles well with the active site structure of blue multicopper oxidases. The $Cu\cdot\cdot\cdot{Cu}$ separations of ca. 3.3 $\AA$ in the angular unit is 0.4 $\AA$ shorter than those observed in the active site of the oxidized form of ascorbate oxidase. The complex displays a visible band at 620 nm $(\varepsilon = 500 M^{-1} cm^{-1})$ in DMSO. It shows magnetic moment values of 3.07 and 2.18 $\mu$B at 300 and 18 K, respectively, for the $Cu_3$ cluster. The complex models the structural and magnetic properties of the trinuclear active site of blue copper oxidases.

Item Type:	Journal Article
Publication:	Polyhedron
Publisher:	Elsevier
Additional Information:	The copyright belongs to Elsevier.
Keywords:	Tricopper(II) complex;Schiff bases;Ascorbate oxidase model;Crystal structure;Magnetic properties
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	30 May 2006
Last Modified:	19 Sep 2010 04:27
URI:	http://eprints.iisc.ac.in/id/eprint/7085

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