Structure and Bonding of Low-Valent (Fischer-Type) and High-Valent (Schrock-Type) Transition Metal Carbene Complexes

The nature and reactivity of the metal–carbene bond of 12 Fischer- (1) and Schrock- (2) type carbene complexes of tungsten, both neutral and negatively charged, is investigated. The geometries and tungsten–carbene bond dissociation energies were calculated by use of ab initio methods at the HF, MP2, and CCSD(T) level of theory.