Kinetic investigation of hydroxide ion and DNA attack on some high spin iron (II) chelates Bearing ONO Donors amino acid Schiff bases

Abstract

The reactivity of few novel high spin Fe(II) complexes of Schiff base ligands derived from 2-hydroxynaphthaldehyde and some variety of amino acids with OH- ion has been examined in aqueous mixture at temperature in the range 10–40 Co. Based on the kinetic investigations, the rate law and a plausible mechanism were proposed and discussed. The general rate equation was suggested as follows: rate = kobs [Complex], where kobs.= k1 + k2 [OH-]. Base catalyzed hydrolysis kinetics measurements imply pseudo-first-order doubly stage rates due the presence of merand fac-isomers. The observed rate constants kobs are correlated the effect of substituent R in the structure of the ligands.From the effect of temperature on the rate; various thermodynamic parameters have been evaluated. The evaluated rate constants and activation parameters are in a good agreement with the stability constants of the investigated complexes. Keywords: Base catalyzed hydrolysis, Isomer, Reaction mechanism, Thermodynamic parameters