Structural and Reaction Chemistry of Tungstenocene Boryl Complexes

The structural and reaction chemistry of Cp 2 W(H)(Bcat) (cat = O 2 C 6 H 4 ) ( 1 ) and Cp 2 W(Bcat‘) 2 (cat‘ = O 2 C 6 H 3 - t -Bu or O 2 C 6 H 2 - t -Bu 2 ) ( 2a,b ) is reported. Compound 1 was prepared by reaction of the anion [Cp 2 WH] - 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.