ELECTRON-DISTRIBUTION IN A STABLE CARBENE

The synthesis and characterization of the stable carbene perdeuterio-1 ,3,4,5-tetramethylimidazol-2-ylidene (2) are reported. The neutron and X-ray diffraction data from single crystals of this perdeuterocarbene are used to determine the electron distribution in the molecule. Neut ron diffraction data were collected at 80 and 173K on 2. The experimen tally determined electron density is very closely matched by density f unctional calculations which show that 2 is a true carbene with neglig ible ylidic character.