Tellus in, tellus out: the chemistry of the vanadium bis(telluride) functionality.

The vanadium-bis(telluride) complex, [(PNP)V(Te)(2)] (see picture), in which the terminal telluride units can act as leaving groups or protecting groups, is prepared by activation of elemental Te by V. The complex masks {(PNP)V(I)} or {(PNP)V(III)} sources when exposed to oxidants such as azides and diphenyldiazomethane. Isocyanides promote elimination of one Te ligand to furnish a V(III) complex with a terminal telluride ligand.