357644-98-5Relevant academic research and scientific papers
Lanthanide(II) complexes bearing linked cyclopentadienyl-anilido ligands: Synthesis, structures, and one-electron-transfer and ethylene polymerization reactions
Hou, Zhaomin,Koizumi, Take-Aki,Nishiura, Masayoshi,Wakatsuki, Yasuo
, p. 3323 - 3328 (2001)
Reactions of Ln[N(SiMe3)2]2(thf)2 Ln = Sm, Yb) with 1 equiv of (C5Me4H)SiMe2NHPh afforded the first linked cyclopentadienyl-anilido (or amido) lanthanide(II) complexes Me2-Si(C5Me4)(NPh)Ln(thf)x (1, Ln = Yb, x = 3; 2, Ln = Sm, x = 0-1) in 75-84% isolated yields. Recrystallization of 1 from toluene/hexane yielded the less solvated complex [Me2Si(C5Me4)-(NPh)Yb(thf)]2 (1′). Complex 1 adopts a monomeric structure containing one chelating Cp-anilido ligand and three thf ligands, while 1′ forms a dimeric structure through an intermolecular Yb-Ph π-interaction. Reaction of 1 or 1′ with azobenzene gave the binuclear Yb(III) complex Me2Si(C5Me4)(NPh)Yb(thf)(μ,η2 : η3-N2Ph2)Yb (NPh)(C5Me2 (3), which contains a cis-oriented azobenze dianion unit bonding in a η3 fashion to one Yb atom and in a η2 fashion to the other Yb atom. Reaction of 1 with 1 equiv of fluorenone gave the corresponding Yb(III) ketyl complex Me2Si(C5Me4)(NPh)Yb(thf)2 (OC13H8) (4) in 75% isolated yield. Treatment of 4 with hexane/ether led to formation of the pinacolate complex [Me2Si-(C5Me4)(NPh)Yb(thf)2 (μ-O2C26H16 (5), in which the pinacolate unit is arranged in a gauche conformation. Dissolving of 5 in THF cleaved the central C-C bond of the pinacolate unit in 5 and regenerated 4 quantitatively. The Sm(II) complex 2 showed moderate activity (44.8 kg of polymer (mol of Sm)-1 h-1) for the polymerization of ethylene under 1 atm at room temperature, yielding linear polyethylene with Mn = 7.26 × 105 and Mw/Mn = 1.58.
