Neutral Chromium Complex with a Cr≡Si Triple Bond: Synthesis and Photoinduced H-H and Benzene C-H Bond Activation.

A neutral silylyne complex with a Cr≡Si triple bond was prepared by dehydrogenation of a chromium silylene complex with Cr-H and Si-H bonds, and was isolated as monomeric crystals, unlike dimeric forms of its tungsten and molybdenum congeners. The strong Cr(δ-)-Si(δ+) bond polarity was revealed by the reaction with MeOH and DFT calculations. The chromium silylyne complex reacted with H2 under LED (365 nm) irradiation to reproduce the precursor silylene complex with a (H)Cr=Si(H) moiety, as a result of 1,2-H-H addition across the Cr≡Si triple bond. Similarly, the chromium silylyne complex reacted with benzene under irradiation to afford an 1,2-addition product with a (H)Cr=Si(Ph) moiety, via benzene C-H bond activation accompanied by Si-C bond forming.

Lewis Base Adducts of Phosphine-Stabilized Pb(II) Cations: Synthesis and Catalytic Hydroamination of Alkynes.

Phosphine-stabilized Pb(II) cations, generated by chloride abstraction from chloroplumbylene 1, readily react with Lewis bases (L) such as phosphines and amines to give the corresponding donor-acceptor complexes 3. These complexes 3 react with phenylacetlylene via alkyne insertion into the Pb-L bond to afford the corresponding vinylplumbylenes 4. Of particular interest, the stable complex 4-HNiPr2 (with a secondary amine) can be used as a hydroamination catalyst of phenylacetylene.