Preparation and Reactivity of Stannyl Complexes of Manganese and Rhenium

The trichlorostannyl complexes M(SnCl3)(CO)nP5-n (1−3: M = Mn, Re; P = PPh(OEt)2 (a), P(OEt)3 (b); n = 2, 3) were prepared by allowing chloro MCl(CO)nP5-n compounds to react with an excess of SnCl2·2H2O. Treatment of compounds 1−3 with NaBH4 in ethanol yielded the tin polyhydride derivatives M(SnH3)(CO)nP5-n (4−6). Treatment of 1−3 with MgBrMe gave the trimethylstannyl complexes M(SnMe3)(CO)nP5-n (7−9), and the reaction of 1−3 with MgBr(C≡CH) yielded the trialkynylstannyl derivatives M[Sn(C≡CH)3](CO)nP5-n (10, 11). The alkynylstannyl complexes M[Sn(C≡CR)3](CO)nP5-n (12−14: R = p-tolyl) were also prepared by allowing M(SnCl3)(CO)nP5-n compounds to react with Li+[C≡CR]- in thf. The complexes were characterized by spectroscopy and by X-ray crystal structure determinations of 4a, 6b, and 9b. Reaction of the tin trihydride complexes Re(SnH3)(CO)2P3 (6) with CO2 (1 atm) led to the binuclear OH-bridging bis(formate) derivatives [Re{Sn[OC(H)=O]2(μ-OH)}(CO)2P3]2 (15). A reaction path for the formation of 15, involving the tin hydride bis(formate) intermediate Re[SnH{OC(H)=O}2](CO)2P3, is discussed. The X-ray crystal structure of 15b is reported.