Biomimetic oxidation of catechol employing complexes formed in-situ with NH-pyrazole ligands and transition metallic salts

A. Mouadili, F. Abrigach, M. K

Abstract

In the present paper, our main objective is to describe the catalytic properties of the complexes formed in-situ with the NH-pyrazole ligands: L1-L7 and different metallic salts (Cu(CH3COO)2, CuSO4, Cu(NO3)2, NiCl2, Co(NO3)2, ZnCl2), which aimed to mimic the active site of catechol oxidase. In order to determine factors influencing the catecholase activity of these complexes, the effect of ligand concentration and the nature of solvent have been studied. The highest rate of catechol oxidation is given by the combination formed by one equivalent of ligand L4 and two equivalents of Cu(CH3COO)2 in THF which equal to 27,449 μmol.L-1min-1. The michaelis-Menten model is applied to obtain the kinetic parameters of the best catalyst.