SYNTHESIS OF AXIALLY ASYMMETRIC N-FUNCTIONALIZED METAL DIALKYLS AND BIMETALLIC COMPLEXES - X-RAY STRUCTURES OF ME2M(L'L') (M = SI, SN L'L' = (CHSIME3C5H3N)(2)) AND ME2SN(L'L')W(CO)(4)

Treatment of dilithium dialkyl compounds derived from dilithiation of 3,3'-dimethyl-2,2'-bipyridine and its trimethylsilylated compound with R'2MCl2 afford axially asymmetric metal dialkyls R'M-2(LL) (R' = Me, LL = (CH2C5H3N)(2), M = Si (2), Sn (3)) and R'M-2(L'L') (R' = Me, L'L' = (CHSiMe3C5H3N)(2), M = Si (4), Ge (5), Sn (6); R' = Ph, M = Sn (7)) , respectively. Compounds 5-7 can react further with W(CO)(6) to form bimetallic complexes R'M-2(L'L')W(CO)(4) (R' = Me, M = Ge (8), Sn (9); R' = Ph, M =; Sn (10)) via the coordination of the two pyridyl nitrog ens. The variable-temperature H-1 NMR spectra of 2-4 have been recorde d to investigate the fluxional behavior due to the torsional motion al ong the C-C axis that joins the two pyridine groups. X-ray structures of compounds 4, 6, and 9 have been determined.