Synthesis, characterisation and reactions of 1,3-bis(trimethylsilyl)-1-aza-allyl-lanthanide complexes;: X-ray structures of [Sm(LL′)2I(thf)], [Yb(LL′)2] and [RN=C(But)CH(R)]2 (thf=tetrahydrofuran, LL′=η3-N(R)C(But)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 synthesised by the reaction of the appropriate lanthanide(II) or lanthanide(III) halide with two equivalents of 1,3-bis(trimethylsilyl)-1-aza-allyl-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 equivalents 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 identified 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 additionally characterised by single crystal X-ray diffraction. (C) 1997 Elsevier Science S.A.