Thermodynamic studies of 5-(p-bromophenylazo)‎-3-phenylrhodanine and its metal complexes

الملخص EN

The dissociation constant of 5-(p-bromophenylazo)-3-phenylrhodanine (HL) and metal-ligand stability constants of its complexes with bivalent (Mn2+, Co2+, Ni2+ and Cu2+) metal ions have been determined potentiometrically in 0.1 M KCl and 40 % (v/v) ethanol-water mixture.

The order of the stability constants of the formed complexes was found to be Mn2+ < Co2+ < Ni2+ < Cu2+.

The effect of temperature was studied and the corresponding thermodynamic parameters (ΔG, ΔH and ΔS) were derived and discussed.

The dissociation process is nonspontaneous, endothermic and entropically unfavorable.

The formation of the metal complexes has been found to be spontaneous, exothermic and entropically favorable.