Formation of Dimers That Contain Unbridged W(IV)/W(IV) Double Bonds

A tungsten neopentylidene complex has been found to decompose to yield a heterochiral dimer that contains a WW double bond and no bridging ligands. Decompositions of related bisalkoxide complexes also yield compounds that contain an “unsupported” WW double bond, while a sample of [Mo(NAr)(CH2-t-Bu)(OC6F5)]2 has been found to be a homochiral species related to [W(NAr)(CH2-t-Bu)(OC6F5)]2.