NOVEL CYCLOPENTADIENYL-FREE ORGANOLANTHANIDES - THE FIRST EXAMPLES OF5-MEMBERED AMIDOLANTHANIDE HETEROCYCLES

Reaction of LnCl(3) (Ln = Nd, Gd, Yb) and [{Me(2)SiN(R)Li}(2)] (R = t- Bu, Ph) give the chloride-bridged dimers {{(t-Bu)NSiMe(2)SiMe(2)N(t-Bu )}Ln(mu-Cl)(THF)}(2)] (1, Ln = Nd; 2, Ln = Gd; 3, Ln = Yb) and [{{(Ph) NSiMe(2)SiMe(2)N(Ph)}Ln(mu-Cl)(THF)(2)}(2)] (4, Ln = Nd; 5, Ln = Gd; 6 , Ln Yb) in good yields. Compounds 2 and 5 were structurally character ized by X-ray crystallography: 2, triclinic, <P(1)over bar>, a = 10.32 1(2) Angstrom, b = 11.116(2) Angstrom, c = 13.434(3) Angstrom, alpha = 107.57(3)degrees, beta = 111.31(3)degrees, gamma = 90.67(3)degrees, V = 1356.1(5) Angstrom(3), Z = 1, R = 0.0233; 5, monoclinic, P2(1)/n, a = 13.913(13) Angstrom, b = 12.914(9) Angstrom, c = 16.434(14) Angstro m, beta = 105.64(3)degrees, V = 2843(4) Angstrom 3, Z = 2, R = 0.0281. The chloro functions in 1-6 remain reactive, demonstrated by the isol ation of the trifluoroacetate derivatives of 1 and 2. Treatment of 1 o r 2 with 2 equiv of NaOCOCF3 gives -Bu)NSiMe(2)SiMe(2)N(t-Bu)}Ln(mu-OC OCF3)(THF)}(2)] (7, Ln = Nd; 8, Ln Gd). The structure of 8 was determi ned by a single-crystal X-ray diffraction analysis. Crystal data for 8 : triclinic, <P(1)over bar>, a = 11.045(2) Angstrom, b = 16.120(3) Ang strom, c = 16.949(3) Angstrom, alpha = 66.17(3)degrees, beta = 85.51(3 )degrees, gamma = 78.27(3)degrees, V = 2702.9(9) Angstrom(3), Z = 2, R = 0.0311. The structure of 8 shows the trifluoroacetate group adoptin g a bridging bidentate mode of coordination.