Potentiometric and Thermodynamic Studies of Some Azosulfoxine Derivatives and Their Metal Complexes
Pages 191-196
A.A.El-Bindary, A.Z. El-Sonbati, M.A. Diab and A.M. Barakat

DOI: http://dx.doi.org/10.6000/1929-5030.2013.02.03.4

Published: 31 August 2013

Abstract: The proton-ligand dissociation constants of some azosulfoxine derivatives and metal-ligand stability constants of their complexes with the metal ions (Mn²⁺, Co²⁺, Ni²⁺ and Cu²⁺) have been determined potentiometrically in 0.1 MKCl and 50 % (by volume) DMF–water mixture at (298, 308 and 318) K. The stability constants of the formed complexes increases in the order Mn²⁺, Co²⁺, Ni²⁺ and Cu²⁺. The effect of temperature was studied and the corresponding thermodynamic parameters (∆G, ∆H and ∆S) were derived and discussed. The dissociation process is non-spontaneous, endothermic and entropically unfavourable. The formation of the metal complexes has been found to be spontaneous, endothermic and entropically favourable.