GROUP-6 METALLOCENE(IV) MAIN-GROUP METAL-COMPLEXES - SYNTHESIS AND STRUCTURES OF A MO-B-LI COMPOUND AND OF [W(ETA-C5H5)(2)H(SNCL2CH(SIME(3))(2))]

The reaction between [{Mo(eta-C5H5)(2)H(mu-Li)}(4)] la, B(C(6)H(2)Bu(3)(t)-2.4.6)Cl-2 and Me(2)NCH(2)CH(2)NMe(2) (tmen) afforded the crystalline complex [Mo(eta-C5H5) H-2{(C6H4)BH(C(6)H(2)Bu(2)(t)-4,6-CMe(2)CH(2)-2)}{Li(tmen)}] 1, having single hydride bridges between Li and Mo (H-a) and Li and B (H-c). A single-crystal structure analysis gave the bond distances Mo-M(a) 1.66(5), Mo-H-b 1.44(6), Li-H-a 1.67(6), LI-H-c 1.90(6), B-H-c 1.21(5), Mo ... Li 3.08(1) and Li ... B 2.63(1) Angstrom. Detailed multinuclear NMR spectroscopic data for 1 showed that the same structure was retained in [H-2(8)]toluene solution. From lb (the tungsten equivalent of la) and SnX(2)R'(2) [R' = CH(SiMe(3))(2), X = F or Cl] or SnCl(3)R' (prepared from SnCl4 and LiR') the new W-Sn complexes [W(eta-C5H5)H(Y)] [Y = SnCl(2)R' 2. SnCl(Me)R', SnFR'(2) or SnClR'(2)] were prepared and characterised. A single-crystal structure determination of 2 gave W-Sn 2.706(1), Sn-C 2.180(8) and average Sn-Cl 2.423(3) Angstrom.