ISSN:
1572-8927
Keywords:
Ternary complexation
;
manganese(II)
;
cadmium(II)
;
1,10-phenanthroline; 2,2′-bipyridine
;
halide ions
;
thiocyanate ion
;
titration calorimetry
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Ternary complexation of manganese(II) and cadmium(II) with1,10-phenanthroline (phen), and halide (chloride, bromide) or pseudohalide (thiocyanate) ions asligands has been studied by precise titration calorimetry inN,N-dimethylformamide (DMF) at 25°C. Data obtained for the ternary system were analyzed onthe basis of thermodynamic parameters for the binary MII-phen and MII-X-(M= Mn or Cd, X = Cl, Br, or SCN) systems. In the binary MII-phen system,formation of a series of mono- to tris- 1,10-phenanthroline complexes isestablished and the formation constants and reaction enthalpies and entropies areobtained. Thermodynamic parameters of complexation for the MII-X- systemshave previously been obtained. All titration curves obtained in the ternary systemsare explained well in terms of formation of mononuclear complexes of the type[MX m (phen) N ](2−m)+. With manganese(II), formation of [MnX(phen)]+,[MnX2(phen)], [MnX3(phen)]−,[MnX(phen)2]+, and[MnX2(phen)] is establishedfor X = Cl and SCN, and [MnX(phen)]+, [MnX2(phen)], [MnX(phen)2]+, and[MnX2(phen)2] for X = Br. With cadmium(II), formation of [CdX(phen)]+,[CdX2(phen)], [CdX3(phen)]−, [CdX(phen)2]+, and [CdX2(phen)2], is establishedfor X = Cl and Br, and [CdX(phen)]+, [CdX2(phen)], [CdX(phen)2]+, and[CdX2(phen)2] for X = SCN. The formation constants, and reaction enthalpiesand entropies are obtained. The results are discussed in comparison with thosefor the corresponding 2,2′-bipyridine systems.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1005173215167
