Molecular mechanics force field based on Gillespie-Kepert model: application to zinc(II) and cadmium(II) complexes with amino- and pyridil-containing ligands

International symposium CACR-96 (Computer assistance to chemical research), Book of Abstracts, p. 72-73 (1996); Bull. Russian Academy of Sciences (1997), submitted

ABSTRACT. Molecular mechanics with Gillespie-Kepert force field (GKFF) was applied to the modelling of zinc(II) and cadmium(II) complexes with amino- and pyridil-containing ligands. Despite active interest to a zinc complexes ( for example, in bioinorganic chemistry), the comprehensive force field for a large number of polydentate ligands is not developed so far. The problem is especially difficult as zinc forms complexes of various coordination numbers. We established forcee field parameters and calculated geometry for more than 20 complexes of zinc(II) and cadmium(II) with high accuracy. The typical root-mean-square deviation calculations - experiment (X-ray) is 0.02 A in bond lengths, 2.0 deg in bond angles and 4.0 deg in torsion angles. Most importantly, we can successfully reproduce the structure of zinc complexes of coordination number 4, 5 and 6 with the same set of MM parameters. The established force field has been used for investigation of size-match selectivity of macrocycles and polydentate open-chain ligands. The correlations between calculated strain energies and experimental data of stability constants and enthalpies for a wide number of complexes of metals is discussed.

Laboratory of Preconcentration