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The ability of the coordinatively saturated, 18-electron Cp*(H)RuCHR complex 1to serve as a masked source of the coordinatively unsaturated Cp*Ru-CH2R species 2via 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 1to an atmosphere of CO or to an equivalent of either PMe3or PH2Ph afforded the corresponding 2·Ladduct (L = CO, 98%; PMe3, 93%; PH2Ph, 67%). Treatment of 1with Ph2SiH2, PhSiH3, Ph2SiClH, or PhSiClH2afforded the corresponding net Si−H addition product, 3a−d(82−94%); an NMR spectroscopic investigation of the analogous reaction of 1with Ph2SiD2provided evidence in support of a reaction mechanism involving previously undocumented Si−H addition across the RuC unit in 1in the formation of 3a. Addition of Jutzi’s acid (H(OEt2)2B(C6F5)4) to 1resulted in the quantitative formation of 4(the N-C-Hcyclometalated variant of [Cp*Ru(κ2-2-NMe2-3-PiPr2-indene)]+B(C6F5)4−). In monitoring the progress of the reaction of 1with excess catecholborane (HBcat), evidence for the formation of the B−H addition product 5iwas obtained en route to the isolable (Bcat)RuC species (5, 54%). Conversely, no intermediates were observed in the reaction of 1with mesitylborane (MesBH2) leading to the Cp*Ru(P,N) complex 6(81%), which features a tethered borane fragment and a Ru−H−B bridge. Crystallographic characterization data are provided for 2·PMe3, 3a, 3b, 3d, 5, and 6. [ABSTRACT FROM AUTHOR]

The synthesis of coordinatively unsaturated Ru, Rh, Pd, and Pt complexes supported by the new pincer-like bis(phosphino)silyl ligand [κ 3-(2-Ph 2PC 6H 4) 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. [ABSTRACT FROM AUTHOR]

The synthesis and reactivity of coordinatively unsaturated Rh and Ir complexes supported by the new bis(phosphino)silyl pincer ligand [κ3-(2-Cy2PC6H4)2SiMe]− ([Cy-PSiP]−) are reported, including the first example of facile, room temperature intermolecular arene C–H bond activation mediated by a silyl pincer complex. [ABSTRACT FROM AUTHOR]