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A comparative thermal decomposition kinetic investigation on Fe(III) complexes of a antipyrine Schiff base ligand, 1,2-Bis(imino-4’-antipyrinyl)ethane (GA)), with varying counter anions viz. CIO4-, NO3-, SCN-, Cl-, and Br-, has been done by thermogravimetric analysis by using Coats-Redfern equation. The kinetic parameters like activation energy (E), pre-exponential factor (A) and entropy of activation (ΔS) were quantified. On comparing the various kinetic parameters, lower activation energy was observed in second stage as compared to first thermal decomposition stage. The same trend has been observed for pre-exponential factor (A) and entropy of activation (ΔS). The present results show that the starting materials having higher activation energy (E), are more stable than the intermediate products, however; the intermediate products possess well-ordered chemical structure due to their highly negative entropy of activation (ΔS) values. The present investigation proves that the counter anions play an important role on the thermal decomposition kinetics of the complexes.

Schiff base ligand (L) derived from glyoxal and 4-aminoantipyrine was synthesized. The ligand (L) has been characterized by IR, NMR, electronic spectral studies and electrochemical studies. Cu(II) complexes of a Schiff base ligand (L) from 4-aminoantpyrine and glyoxal having the composition [CuL1]X2 where X = Cl¯ or NO3¯ have been prepared and characterized by elemental analysis, electrical conductivity in non-aqueous solvent, infrared and electronic, as well as cyclic voltammetric studies. L acts as a neutral tetradentate ligand coordinating through both the carbonyl oxygen and azomethine nitrogen. On both the complexes both the anions are not coordinated. A square planar geometry is assigned for complexes. The electrochemical studies of ligand show a typical cyclic voltammogram for an irreversible process. While copper(II) complexes show the typical cyclic voltammograms for quasi reversible process.