Summary.
The dissociation constants of 3-phenylsulfonamidorhodanine (PSR) were determined potentiometrically in 0.1 M KCl and 20% (v/v) ethanol-water. The stepwise stability constants of the complexes of Mn2+, Co2+, Ni2+, Cu2+, Zn2+,La3+, Ce3+, Gd3+, UO2+ 2, and Th4+ with PSR were determined. The stabilities of the complexes were found as follows: Th4+ > UO2+ 2 > Gd3+ > Ce3+ > La3+ > Mn2+< Co2+ < Ni2+ < Cu2+ > Zn2+. The thermodynamic parameters for PSR and its complexes were evaluated and discussed. The dissociation process is non-spontaneous, endothermic, and entropically unfavourable. The formation of the complexes was found to be spontaneous, exothermic or endothermic (depending on the metal), and entropically favourable. The stoichiometries of the complexes were determined spectrophotometrically and indicate the formation of 1:1 and 1:2 (metal:ligand) complexes..
Zusammenfassung.
Die Dissoziationskonstanten von 3-Phenylsulfonamidorhodanin (PSR) in 0.1 M KCl und 60% (v/v) Ethanol-Wasser wurden potentiometrisch ermittelt. Die stufenweisen Stabilitätskonstanten seiner Komplexe mit Mn2+, Co2+ Ni2+, Zn2+, La3+, Ce3+, Gd3+, UO2+ und Th4+ wurden bestimmt. Die Stabilitätsreihenfolge lautet Th4+ > UO2+ > Gd3+ > La3+ > Mn2+ < Co2+< Ni2+ < Cu2+ > Zn2+. Die thermodynamischen Parameter von PSR und seinen Komplexen werden diskutiert. Der Dissoziationsprozeß verläuft nicht-spontan, endotherm und entropisch ungünstig. Die Komplexbildung ist spontan, exo- oder endotherm je nach Metall und entropisch begünstigt. Die Zusammensetzung der Komplexe wurde spektrophotometrisch bestimmt; es entstehen 1:1- und 1:2-Komplexe (Metall:Ligand)..
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Received March 11, 1998. Accepted (revised) May 29, 1998
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El-Bindary, A., Ghoneim, M., El-Sonbati, A. et al. Thermodynamics of Substituted Rhodanine III: Potentiometric and Spectrophotometric Studies of Complexes of Some Transition Metals with 3-Phenylsulfonamidorhodanine. Monatshefte fuer Chemie 129, 1259–1265 (1998). https://doi.org/10.1007/PL00010137
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DOI: https://doi.org/10.1007/PL00010137