Part I. Aromatic ortho-hydroxycarboxylic acids, Pure Appl. Chem. 69, 329-381 (1997

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The formation of Ag(I) complexes with 2,2'-bipyridine (bipy), 2,2'6',2' '-terpyridine (terpy), 2-(aminomethyl)pyridine (amp), and bis((2-pyridyl)methyl)amine (dpa) is studied in dimethyl sulfoxide (dmso) by means of potentiometric and calorimetric measurements. Enthalpy-stabilized mononuclear MLj complexes are formed, whereas entropy changes counteract complex formation. Additionally, a comparison with analog Ag-polyamine species is made to evidence the significant different coordination behavior of these classes of ligands. The results are discussed in terms of different basicity and steric requirements of the ligands and solvation effects. The dpa ligand, with an unprecedented coordination pattern, forms also a bimetallic complex [Ag2(dpa)2]2+ that has been structurally characterized in the solid state by X-ray diffraction. The influence of solvent, water and dmso, on the binding energy of the monodentate pyridine to Ag(I) has also been assessed by means of density functional theory (DFT) calculations. This study has been extended also in vacuum to the reaction of Ag(I) with the simple monoamine methylamine (mea). These results are correlated with the experimental evidence and used to interpret the different affinities of pyridine for the Ag(I) ion in the two media.

A new algorithm for simulation of chemical equilibria is developed, based on classical Newton-Raphson method applied to mass balance. This tool, named EST (Equilibrium Speciation Tool), is improved by using a robust Genetic Algorithm. In addition, EST works by using Excel spreadsheets and therefore offers the innovation of a great simplicity and versatility. In fact, it allows the users to simulate, or to obtain from experimental data, desired chemical-physical parameters as well as to interact with other available or freely created Excel tools. The reliability of this utility is here proved by comparison with some published data by other authors, concerning both complicated homogeneous and heterogeneous equilibria. In addiction its flexibility is tested computing thermodynamic parameters by using experimental calorimetric data referred to the complex formation of cobalt(II) with a macrocyclic ligand. A brief review and comparison of the relative robustness and quickness of main numerical methods are also reported.