Potentiometric, Spectroscopic and Voltammetric Studies on the Complex Formation of Iron(III), Copper(II) and Nickel(II) with Substituted Hydroxamic Acid Type Ligands

Abstract

In order to establish the biological importance of hydroxamic acids derivatives the acid dissociation constants (ionization constants) were determined by potentiometric and spectroscopic methods. The possible correlation of the experimental values with theoretical values was examined using Gaussian 98 suit, hi potentiometric method the data were analyzed by three analytical procedures such as Bjerrum method, Irving and Rossotti method and Sarkar and Kruck method. It has been found that the pKa values obtained by these three methods are in good agreement with each other. The modified limiting absorption method was used to calculate the ionization constants in spectroscopic method. In the case of Nsubstituted hydroxamic acids, the relative order of pKa values in 1:1 ethanol is as follows: