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Thermodynamics of Complexation of Cadmium(II) by Open‐Chain N‐Donor Ligands in Dimethyl Sulfoxide Solution
Author(s) -
Comuzzi Clara,
Grespan Michela,
Melchior Andrea,
Portanova Roberto,
Tolazzi Marilena
Publication year - 2001
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200112)2001:12<3087::aid-ejic3087>3.0.co;2-4
Subject(s) - chemistry , ethylenediamine , diethylenetriamine , potentiometric titration , dimethyl sulfoxide , inorganic chemistry , metal ions in aqueous solution , enthalpy , medicinal chemistry , ionic strength , steric effects , chelation , metal , organic chemistry , ion , aqueous solution , physics , quantum mechanics
Abstract Thermodynamic parameters for the complexation of Cd II by the amines n ‐butylamine ( n ‐but), ethylenediamine (en), N , N ′‐dimethylethylenediamine (dmen), N , N , N ′‐trimethylethylenediamine (trmen), N , N , N ′, N ′‐tetramethylethylenediamine (tmen), diethylenetriamine (dien), N , N ′′‐dimethyldiethylenetriamine (dmdien), and N , N , N ′, N ′′, N ′′‐pentamethyldiethylenetriamine (pmdien) have been determined in dimethyl sulfoxide (DMSO) solution by potentiometric and calorimetric techniques at 298 K and 0.1 mol dm −3 ionic strength (NEt 4 ClO 4 ). Only mononuclear complexes are formed, in which the polyamines act predominantly as chelating agents. All the complexes are enthalpy‐stabilized, whereas the entropy changes counteract the complexation. The steric requirements of the donors have a strong influence on the stoichiometry and nature of the Cd II complexes formed. Comparisons are made with data reported for some of these systems in water and with available data on silver(I) complexation by the same amines in DMSO, the latter showing that the selectivity of the ligands towards metal ions is also influenced by N ‐alkylation.