Structural and Reaction Chemistry of Tungstenocene Boryl Complexes

The structural and reaction chemistry of Cp2W(H)(Bcat) (cat = O2C6H4) (1) and Cp2W(Bcat')2 (cat' = O2C6H3-t-Bu or O2C6H2-t-Bu2) (2a,b) is reported. Compound 1 was prepared by reaction of the anion [Cp2WH]- with ClBcat, and 2a,b were prepared by oxidative addition of cat'BBcat' by photochemical or thermal generation of tungstenocene. The X-ray structures of 1 and 2a are reported, and they display geometries indicating dπ−pπ interaction. The reaction chemistry of these compounds with small molecules involves protonation by alcohols, water-catalyzed protonation by amines, halogenation of the hydride in 1, and resistance toward formation of Lewis acid−base complexes. In addition, 1 undergoes photochemically induced reductive elimination of HBcat. Remarkably, generation of tungstenocene in the presence of cat'BBcat' in benzene solvent led to the formation of 2 rather than oxidative addition of the solvent.