The heteroatom-stabilized carbene complexes of the group 6 transition metals (Fischer carbene Complexes') were the first to be prepared2 and are among the most stable of all transition-metal carbene c~ mplexes.~ The chemical and physical properties of these complexes have been interpreted in terms of a polarized chromium-carbon bond with the carbon bearing an appreciable positive~ harge.~ J An example is the tremendous ...
