N,N'-Diisopropyl-N' '-bis(trimethylsilyl)guanidinate Ligand as a Supporting Coordination Environment in Yttrium Chemistry. Synthesis, Structure, and Properties of Complexes [(Me
文摘
The reaction of anhydrous YCl3 with an equimolar amount of lithium N,N'-diisopropyl-N' '-bis(trimethylsilyl)guanidinate,Li[(Me3Si)2NC(Ni-Pr)2], in tetrahydrofuran (THF) afforded the monomeric monoguanidinate dichloro complex {(Me3Si)2NC(Ni-Pr)2}YCl2(THF)2 (1). Alkylation of complex 1 with 2 equiv of LiCH2SiMe3 in hexane at 0 C yielded themonomeric salt-free dialkyl complex {(Me3Si)2NC(Ni-Pr)2}Y(CH2SiMe3)2(THF)2 (2). The bis(triethylborohydride) complex[(Me3Si)2NC(Ni-Pr)2]Y[(-H)(-Et)2BEt]2(THF) (5) was prepared by the reaction of complex 1 with 2 equiv of LiBEt3Hin a toluene-THF mixture at 0 C. The complexes 1, 2, and 5 were structurally characterized. Complex 2 as wellas the systems 2-Ph3B, 2-Ph3B-MAO, and 1-MAO (MAO = methylaluminoxanes) in toluene were inactive inethylene polymerization, while the product obtained in situ from the reaction of complex 2 with a 2-fold molarexcess of PhSiH3 in toluene polymerized ethylene with moderate activity.