Molecular mechanics calculations of beta-diketonate, aqua, and aqua-beta-dicetonate complexes of lanthanide ions using Gillespie-Kepert model

M.G. Razumov, V.L. Melnikov, I.V. Pletnev

J. Comp. Chem., v. 22 (1), p.38-50 (2001)

ABSTRACT. A version of molecular mechanics based on the Gillespie-Kepert model of coordination bonds "repulsion" is applied to lanthanide complexes. The force field parameters are developed which describe the structure of b-diketonate-, aqua-, and mixed aqua-b-diketonate complexes with good accuracy; the same parameters are applicable to various coordination numbers/polyhedra. For the aqua complexes, typical root-mean-square deviation (calculated vs. X-ray experimental values) is 0.02 A in Ln-O bond lengths and 2.0o in O-Ln-O valence angles. For most of the other compounds, the same precision is achieved in coordination bond lengths, while 3.5o is a typical precision for coordination bond angles. Calculations successfully reproduce the puckering of the b-diketonate chelate rings, as well as the relative stability of isomers for a representative example.

Laboratory of Preconcentration