Structural elucidation of a mononuclear titanium methylidene.

The first example of a structurally characterized titanium methylidene, (PN)2Ti[double bond, length as m-dash]CH2, has been prepared via one-electron oxidation of (PN)2Ti(CH3) followed by deprotonation or by H-atom abstraction using an aryloxyl radical. The Ti[double bond, length as m-dash]C distance was found to be 1.939(3) Å, and variable temperature, multinuclear, and multidimensional NMR spectroscopic experiments revealed the methylidene to engage in long range interactions with protons on the ligand framework. Computational studies showed that the Ti[double bond, length as m-dash]C bond, which until now has eluded structural studies, displays all the hallmarks of a prototypical Schrock-carbene.