Search

The ability of the coordinatively saturated, 18-electron Cp*(H)Ru═CHR complex 1 to serve as a masked source of the coordinatively unsaturated Cp*Ru-CH2R species 2 via reversible α-hydride elimination was surveyed. The rate constant for this dynamic process (300 K, C6D6) was measured to be 59 ± 1 s−1, on the basis of data obtained from selective inversion NMR experiments. Exposure of 1 to an atmosphere of CO or to an equivalent of either PMe3 or PH2Ph afforded the corresponding 2·L adduct (L = CO, 98%; PMe3, 93%; PH2Ph, 67%). Treatment of 1 with Ph2SiH2, PhSiH3, Ph2SiClH, or PhSiClH2 afforded the corresponding net Si−H addition product, 3a−d (82−94%); an NMR spectroscopic investigation of the analogous reaction of 1 with Ph2SiD2 provided evidence in support of a reaction mechanism involving previously undocumented Si−H addition across the Ru═C unit in 1 in the formation of 3a. Addition of Jutzi’s acid (H(OEt2)2B(C6F5)4) to 1 resulted in the quantitative formation of 4 (the N-C-H cyclometalated variant of [...

The synthesis of coordinatively unsaturated Ru, Rh, Pd, and Pt complexes supported by the new pincer-like bis(phosphino)silyl ligand [κ3-(2-Ph2PC6H4)2SiMe]− ([PSiP]) is described. In the first application of silyl pincer-type complexes in transfer hydrogenation catalysis, [PSiP]Ru species were shown to be effective in mediating the reduction of ketones employing basic iPrOH as the hydrogen source.