Alkyl group dependence of C–Si reductive eliminations from alkyl(silyl) Pt(II) complexes: a density functional study

C–Si reductive elimination from Pt(R)(SiPh3)(PMe3)2 (R=Me, Pr) was theoretically studied with the density functional theory. For comparisons with the experiment, substitution of PMe3 with diphenylacetylene was taken into account. The calculated activation barriers in the C–Si elimination step after the ligand exchange were 22.0 and 28.9 kcal mol-1 for R=Me and Pr, respectively, which explains the reactivity difference reported experimentally. In order to analyze the energy difference, we optimized transition states of several model complexes, and examined the influence of the steric repulsion between R and the other ligands. Comparisons of the geometries and the barrier heights reveal that the steric repulsion and the Si–alkyl bond energy are important factors controlling the reaction rate. [Copyright &y& Elsevier]