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(Bu t)CH(R)] 2 (thf = tetrahydrofuran, LL′ = η3-N(R)C(Bu t)CHR, RSiMe 3)

Abstract

Several lantahanide(II) and lanthanide(III) complexes of formula [Ln(LL′) 2X(thf) n ](LL′ = η 3-N(R)C(Bu 1)CHR, R  SiMe 3; X  Cl, n = 1 and Ln  Ce 1 and 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 synthesized 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 = SO 2CF 3). 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 1)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 β-diketiminate [Yb(L′L″) 2][L′L″=N(R)C(Ph)C(H)C(Bu 1)NR]. Complexes 1–8 were identified by C, H and N elemental analysis, multinuclear ( 1H, 13C, 29Si{ 1H}, 17Yb or 19F) NMR and mass spectra, of which 3, 6 and 8 were additionally characterised by single crystal X-ray diffraction.