Ab Initio Study of a Carbene Insertion into a Metal-Hydrogen Bond

Abstract

The insertion of CH_x fragments into metal-hydrogen bonds has long been proposed as the chain initiation step in the Fischer-Tropsch synthesis of alkanes and alkenes. As a model for this important elementary reaction, the mechanism by which CH_2 inserts into a Ru-H bond has been determined by calculations along the reaction path using analytic gradient techniques. The quantitative energetics (activation energy and exothermicity) have been refined using a full valence CI (among the active orbitals) MC-SCF description for each point along the reaction coordinate. Qualitative features of the reaction will be emphasized (e.g. orbital character changes upon approach to the transition state).