Complexation Studies of Zn2+, Cu2+, Co2+, Ni2+ and Cd2+ Ions with a Schiff Base Ligand

Abstract

The complex-formation reactions between Zn²⁺, Cu²⁺, Co²⁺, Ni²⁺ and Cd²⁺ ions with, N,N'–Bis-(salicylidene)1,8-diamino-3,6-dioxaoctan Schiff base ligand, has been studied by spectrophotometric  method in acetonitrile at various temperatures. The formation constant (K_f) and the molar absorptivity (ε) of the resulting complexes between ligand and different cations were calculated by fitting the observed absorbance at various [M²⁺]/[L] mole ratios and found that the stability of the resulting L-M²⁺ complexes varied in the order Cu²⁺ > Zn²⁺ > Co²⁺ > Ni²⁺ > Cd²⁺. The enthalpy and entropy changes of the complexation reaction were determined from the temperature dependence of the formation constants.

DOI: http://dx.doi.org/10.17807/orbital.v9i4.1014