Abstract
Reaction of (PNP)Li with TaF5 produces pentagonal-bipyramidal (PNP)TaF4 (2). Alkylation of 2 with MeMgBr
allows for the isolation of (PNP)TaMe4 (3). (PNP)TaMe4 (3)
evolves thermally and/or photochemically into a bis(methylidene) complex (PNP)Ta(CH2)2 (4). The identity of the latter
has been established by X-ray structural, NMR spectroscopic,
and DFT computational studies. It does not appear that 4
possesses agostic interactions in solution.