Potentiometric and Thermodynamic Studies of 3-(Trichlorophenylsulphonamido)rhodanine Complexes with Some Metal Ions

Acid dissociation and complex stability constants of 3-(tricholophenylsulphonamido)rhodanine (TCSR) with some metal ions were determined potentiometrically in 0.1 KCl and 30% (v/v) sthanol-water mixture. The sequence of stability constants is: Th4 UO2+ 2 Cu2+ Ni2+ Co2+ n2+. The dissociation constants pK11 of TcSR and the stability constants log K of their complexes were determined at 298, 308 and 318 K. The corresponding therodynaic paraeters (deltaG, deltaH and deltaS) 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 endothermic and entropically favourable.