Synthesis and Reactivity of Trihydridostannyl Complexes of Ruthenium and Osmium

Trichlorostannyl complexes M(SnCl3)(Tp)L(PPh3) (1, 2) and M(SnCl3)(Cp)L(PPh3) (5, 6) [M = Ru, Os; L = P(OMe)3 (a), P(OEt)3 (b), PPh(OEt)2 (c), PPh3 (d)] were prepared by allowing chloro complexes MCl(Tp)L(PPh3) and MCl(Cp)L(PPh3) to react with an excess of SnCl2·2H2O in ethanol. Treatment of trichlorostannyl complexes 1, 2, 5, and 6 with NaBH4 in ethanol yielded tin trihydride derivatives M(SnH3)(Tp)L(PPh3) (3, 4) and M(SnH3)(Cp)L(PPh3) (7, 8). Reaction of these complexes with CCl4 gave the trichlorostannyl precursors 1, 2, 5, and 6. Hydridochlorostannyl intermediates Os(SnH2Cl)(Tp)[P(OMe)3](PPh3) (9a) and Os(SnHCl2)(Tp)[P(OMe)3](PPh3) (10a) were also obtained. Reaction of trihydridostannyl complexes M(SnH3)(Tp)L(PPh3) (3, 4) with CO2 (1 atm) led to hydridobis(formate) derivatives M[SnH{OC(H)O}2](Tp)L(PPh3) (11). In contrast, reaction of the related complexes M(SnH3)(Cp)L(PPh3) (7, 8) with CO2 (1 atm) led to the binuclear OH-bridging bis(formate) derivatives [M[Sn{OC(H)O}2(μ-OH)](Cp)L(PPh3)]2 (12, 13). A reaction path for the formation of 12 and 13, involving the mononuclear tin hydride complex M[SnH{OC(H)O}2](Cp)L(PPh3), is discussed. The X-ray crystal structure of 12b is reported. Chlorobis(methyl)stannyl Ru(SnClMe2)(Cp)[P(OEt)3](PPh3) (15b) and trimethylstannyl complexes M(SnMe3)(Tp)[P(OMe)3](PPh3) (14a) and M(SnMe3)(Cp)[P(OEt)3](PPh3) (16b, 17b) were prepared by allowing trichlorostannyl compounds 1, 2, 5, and 6 to react with MgBrMe in diethyl ether. Trialkynylstannyl derivatives M[Sn(CCR)3}(Tp)L(PPh3) (18, 19) and Ru[Sn(CCR)3}(Cp)[P(OEt)3](PPh3) (20b) (R = Ph, p-tolyl) were also prepared from the reaction of trichlorostannyl complexes 1, 2, 5, and 6 with Li+(CCR)− in thf. The complexes were characterized by spectroscopy and by X-ray crystal structure determination of Ru(SnClMe2)(Cp)[P(OEt)3](PPh3) (15b).