Chemical speciation and computer modelling studies on interaction of an antioxidant 7 ,8-dihydroxy-4-methylcoumarin with bivalent metal ions

Abstract

The stability constants of bivalent metal complexes with 7,8-dihydroxy-4-methylcoumarin, an antioxidant are reported. The variation of stability constant with different ionic strengths, temperatures, percentage of solvents, dielectric constants have been studied by potentiometric estimation of H + ions in the solution. The n and pL values, thermodynamic parameters ΔG, AH and AS have been evaluated at 25 ± 0.5 °C. The values of δ min were also evaluated. Species distribution curves are plotted to visualize the nature of 1: 1 and 1: 2 complexation equilibria at different H + ions concentration.