Vinylidenecarbenoid. The importance of solvation and electron correlation effects on its structure

According to ab initio calculations of valence double-zeta quality at RHF and MP2 (CISD) levels of optimization the structure of vinylidenecarbenoid is extremely sensitive to solvation as well as electron correlation effects. Solvation, as mimicked by coordination of three water molecules to lithium, causes a lengthening of the carbon-lithium bond. On the other hand optimization at electron correlation level (MP2) induces a considerable shortening of the carbon-chlorine bond. The importance of this effect in determining the geometry of the carbenoid structure is rationalized in terms of qualitative considerations.