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Bioinorganic Chemistry and Applications
Volume 2007, Article ID 43424, 9 pages
http://dx.doi.org/10.1155/2007/43424
Research Article

Characterization of Cu(II)-ACC Complexes and Conversion of the Bound ACC into Ethylene in the Presence of Hydrogen Peroxide. Detection of a Brown Intermediate at Low Temperature

1BiosCiences FRE CNRS 3005, Faculté des Sciences et Techniques, Université Paul Cézanne Aix-Marseille III, avenue Escadrille Normandie-Niémen, Marseille Cedex 20 13397, France
2Spectropôle, Faculté des Sciences et Techniques, Université Paul Cézanne Aix-Marseille III, avenue Escadrille Normandie-Niémen, Marseille Cedex 20 13397, France
3Central Research Institute for Chemistry, Hungarian Academy of Sciences, P.O. Box 17, Budapest 1525, Hungary

Received 26 March 2007; Accepted 16 July 2007

Academic Editor: Marc Fontecave

Copyright © 2007 Wadih Ghattas et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Two copper(II)-ACC complexes were prepared and characterized: [Cu(bpy)(ACC)(H2O)]CO4 (1) and [Cu(ACC)2]34H2O (2). Their crystallographic structures are described and analyzed. Spectroscopic characterizations (UV-visible and EPR) confirm that the structure is maintained in solution. These complexes are able to produce ethylene in the presence of hydrogen peroxide in an “ACC Oxidase-like” reaction in water and in methanol. The conversion of ACC into ethylene depends on the amount of base, and, in methanol, 3 equivalents of NaOH are needed for optimum activity. The base is proposed to play a role in H2O2 deprotonation. The presence of an exogenic ligand (bpy) is important for the reactivity and may stabilize a reaction intermediate. Indeed, a brown intermediate with an absorption band centered at 433 nm can be detected at low temperature when 1 is treated with 10 equivalents of H2O2.