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Affinity of Polypyridines Towards Cd II and Co II Ions: a Thermodynamic and DFT Study
Author(s) -
Del Piero Silvia,
Di Bernardo Plinio,
Fedele Rosalisa,
Melchior Andrea,
Polese Pierluigi,
Tolazzi Marilena
Publication year - 2006
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/ejic.200600435
Subject(s) - chemistry , pyridine , enthalpy , density functional theory , solvation , steric effects , potentiometric titration , ionic bonding , solvent , bipyridine , ion , protonation , amine gas treating , standard enthalpy of formation , inorganic chemistry , computational chemistry , crystallography , medicinal chemistry , stereochemistry , organic chemistry , thermodynamics , crystal structure , physics
Cd II and Co II complex formation with pyridine (py), 2,2′‐bipyridine (bipy), 2,2′6′,2″‐terpyridine (terpy), 2‐(aminomethyl)pyridine (amp), and bis[(2‐pyridyl)methyl]amine (dpma) was studied at 298 K in the aprotic solvent dimethyl sulfoxide (DMSO) and in an ionic medium set to 0.1 mol dm –3 with Et 4 NClO 4 in anaerobic conditions. Potentiometric, UV/Vis spectrophotometric, and calorimetric measurements were carried out to obtain the thermodynamic parameters of the systems investigated. Enthalpy‐stabilized mononuclear ML j complexes are formed, whereas entropy changes counteract complex formation. These results are discussed in terms of different basicities, steric requirements, and solvation, of both the ligands and the resulting complexes. Density functional theory (DFT) calculations were carried out in order to obtain structural information and binding energies in vacuo. The DFT results are correlated with the solution studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)