Kinetic and Mechanistic Investigations of Cleavage of P-Nitrophenyl Picolinate Catalysed by Ethylenediamine Cobalt(Ii) Complexes

Abstract

Two novel ethylenediamine cobalt(II) complexes, CoL1 and CoL2, were synthesized and characterized, and were used as mimic hydrolases in the catalytic hydrolysis of a carboxylic ester p-nitrophenyl picolinate, (PNPP). Analysis of the specific absorption spectra of the hydrolytic reaction systems indicated that the catalytic hydrolysis involved key intermediates formed by PNPP with the cobalt(II) complexes. A mechanism for the PNPP hydrolysis has been proposed and the associated kinetic parameters have been calculated. The effects of acidity of the buffer solution, of the structure of the complexes, and of temperature on the rate of the catalysed hydrolysis have also been discussed.