SYNTHESIS AND REACTIVITY OF THE OSMATE(0) COMPLEXES M[OS(CO)2(ETA-C5R5)] (M=LI, NA, R=H, ME) - VERSATILE SYNTHONS FOR SYNTHESIS OF ORGANOOSMIUM COMPLEXES

The anionic osmium complex Li[Os(CO)2(eta-C5Me5)] (2a) was synthesized by the reaction of the hydrido complex (eta-C5Me5)Os(CO)2H (3a) with n-BuLi. The unsubstituted cyclopentadienyl derivatives M[Os(CO)2(eta-C 5H5)] (2b, M = Li; 2c, M = Na) were also prepared by an identical meth od or by two-electron reduction of (eta-C5H5)Os(CO)2I with sodium naph thalenide. Reactions of 2a with various electrophiles (CH3I, D2O, Me3S iCl, tBuSiH2Cl, Me3SiSiMe2Cl, Me2SiCl2, and Me3GeCl) afforded the nucl eophilic substitution products (eta-C5Me5)Os(CO)2R (R = CH3, D, SiMe3, SiH2tBu, SiMe2SiMe3, SiClMe2, and GeMe3) in good to excellent yields. Analogous products were also obtained by the reaction of 2b with tBuS iH2Cl and by the reactions of 2c with tBuSiH2Cl and tBuSiHCl2.