Exploring the reactivity of a coordinatively unsaturated Cp*Ru(κ2-P,O) complex with small molecule substrates: application in E–H bond activation (E = H, B, and Si)

Abstract

Treatment of [Cp*RuCl](4) with 1-diisopropylphosphino-2-indanone () afforded Cp*Ru(Cl)(kappa(2)-P,O-) () in 96% isolated yield. Dehydrohalogenation of under an atmosphere of N(2) provided the dinuclear complex (78% isolated yield), which is comprised of two coordinatively unsaturated Cp*Ru(kappa(2)-P,O) fragments () linked by an end-on coordinated micro-N(2) ligand. Although complex has not been observed directly, reactivity studies demonstrated that can serve as a convenient source of . Isolable adducts of were prepared via exposure of to an atmosphere of CO (93% yield, ) or two equivalents of PhCN (91% yield, ). Exposure of to an atmosphere of H(2) afforded the adduct .(sigma-H(2)) () quantitatively; the clean conversion of back into occurred upon evacuation and re-introduction of a N(2) atmosphere. Treatment of with two equivalents of PhSiH(3) or Ph(2)SiH(2) afforded products featuring (H)(2)Ru-SiPhX-O fragments ( and , respectively; both 95% isolated yield) corresponding to net double geminal Si-H bond activation of the organosilane in which the extruded silylene fragment has inserted into the Ru-O bond of the putative intermediate . Similar reactivity was observed upon treatment of with two equivalents of mesitylborane to give (82% isolated yield). While minimal Ru-HSi interactions were identified for , in solution and the solid state, the hydride ligands in were observed to bridge ruthenium and boron. Crystallographic characterization data were obtained for .0.5C(6)H(6), , , and .