Research Article Reactions of polyhomofunctional organic compounds: 3: Kinetics of hydrolysis of ethylene bridged salicylaldimine Schiff base and its mononuclear copper (II) complex

Abstract

Kinetic studies of hydrolysis of the two isochemical azomethine sites present in 1,2-bis(salicylidinimino)ethelene (1) abbreviated as EDA -Sal and one of its novel mononuclear copper (II) complex abbreviated as Cu(EDA - Sal) (2) have been studied in the varied pH range 1-12, and at different temperatures.  The investigations indicate that based on pH,  the aliquot (1) exists in several acid - base forms.  The acid-base equilibrium and resonace effects have been found to be responsible for near simultaneous hydrlysis of azomethine sites present in the molecules.The repetitive spectral profiles of both the selected compunds reveal that  the kinetic mixture exhibit isosbestic points in entire pH range of study, indicating the involvement of only two absorbing species throughout the  reaction path.  The hydrolysis follows pseudo - first order kinetics in both schiff base and its corresponding complex.  Intersetingly, except in acidic range, the complex is found to be stable.  the difference  in rate of hydrolysis of (2) from that of (1)  and the possible influencing factors are  discussed.  By Arrhenius and Eyring methods activation energy E_a  and other thermodynamic parametres such as DH^#, DG^# and DS^#  are evaluted.

Keywords: EDA -Sal; Cu(EDA – Sal); hydrolysis; isosbesticity, Thermodynamic Parameters