Synthesis and spectroscopic characerization of new hydrido and dihydrogen complexes of osmium and ruthenium stabilized by the tris(pyrazolyl)borate ligand

Abstract

The five-coordinate complexes MHCl(CO)(PiPr3)2 (M = Os (1), Ru (2)) react with Na[HBpz3] in methanol at room temperature to give M(η2-HBpz3)H(CO)(PiPr3)2 (M = Os (3), Ru (4)), which in toluene under reflux evolve into M(η3-HBpz3)H(CO)(PiPr3) (M = Os (5), Ru (6)) by dissociation of triisopropylphosphine. The protonation with HBF4 of 5 and 6 in dichloromethane yields the dihydrogen complexes [M(η3-HBpz3)(η2-H2)(CO)(PiPr3)]BF4 (M = Os (7), Ru (8)), from which the dihydrogen ligand can be easily displaced by acetone to afford the solvate compounds [M(η3-HBpz3){η1-OC(CH3)2}(CO)(PiPr3)]BF4 (M = Os (9), Ru (10)).