Valence Bond Concepts Applied to the Molecular Mechanics Description of Molecular Shapes. 3. Applications to Transition Metal Alkyls and Hydrides

Recently we reported a qualitative, valence bond derived model for describing the shapes of transition metal complexes, with a focus on metal hydrides and alkyls. This model, based on the concepts of hybridization and resonance, rationalizes the unusual and varied shapes of hydride and alkyl complexes with transition metals. This paper demonstrates the quantitative incorporation of these valence bond concepts into molecular mechanics algorithms. The resulting force field method (HV-VB) accurately describes the structures of alkyls and hydride complexes of the transition metals. For a wide variety of crystallographically characterized molecules, the HV-VB computations faithfully reproduce the observed structures.