SYNTHESIS, CHARACTERIZATION AND REACTIONS OF 1,3-BIS(TRIMETHYLSILYL)-1-AZA-ALLYL-LANTHANIDE COMPLEXES - X-RAY STRUCTURES OF [SM(LL')(2)I(THF)], [YB(LL')(2)] AND [RN=C(BU-T)CH(R)](2) (THF=TETRAHYDROFURAN, LL'=ETA(3)-N(R)C(BU-T)CHR, R=SIME3)

Several lanthanide(II) and lanthanide(III) complexes of formula [Ln(LL ')(2)X(thf)(n)] (LL' = eta(3)-N(R)C(Bu-t)CHR, R = SiMe3; X = Cl, n = 1 and Ln = Ce 1 or Nd 2; or X = I, n = 1 and Ln = Sm 3; or X = I, n = 0 and Ln = Yb 4), [Sm(LL')(2)(thf)] 5 and [Yb(LL')(2)] 6 have been synt hesised by the reaction of the appropriate lanthanide(II) or lanthanid e(III) halide with two equivalents of 1,3-bis(trimethylsilyl)-1-aza-al lyl-potassium [K(LL')](n). Oxidation of 6 with Ag(OTf) afforded [Yb(LL ')(2)(OTf)] 7 (Tf = SO2CF3). The reaction of 6 with half an equivalent of I-2 yielded as the main oxidative product 4 but also led to ligand coupling, forming [RN = C(Bu '')CH(R)](2) 8, which was also prepared by the reaction of [K(LL')](n) with I-2. Treatment of 6 with two equiv alents of PhCN yielded the previously known beta-diketiminate [Yb(L'L' ')(2)] [L' L'' = N(R)C(Ph)C(H)C(Bu-t)NR]. Complexes 1-8 were identifie d by C, H and N elemental analysis, multinuclear(H-1, C-13, Si-29{H-1} , Yb-17 or F-19) NMR and mass spectra, of which 3, 6 and 8 were additi onally characterised by single crystal X-ray diffraction. (C) 1997 Els evier Science S.A.