6533b852fe1ef96bd12aab37

RESEARCH PRODUCT

Single-Component Polymerization Catalysts for Ethylene and Styrene:  Synthesis, Characterization, and Reactivity of Alkyl and Hydrido Yttrium Complexes Containing a Linked Amido−Cyclopentadienyl Ligand

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Yttrium alkyl complexes Y(η5:η1-C5Me4SiMe2NCMe2R)(CH2SiMe3)(THF) (R = Me, Et) and Y(η5:η1-C9H6SiMe2NCMe3)(CH2SiMe3)(THF) can be prepared in high yields by a σ-bond metathesis reaction between Y(CH2SiMe3)3(THF)2 and amino-functionalized cyclopentadienes or indene. The structure of Y(η5:η1-C5Me4SiMe2NCMe2Et)(CH2SiMe3)(THF) was shown by single-crystal X-ray diffraction to be that of a three-legged piano stool. Reaction of Y(CH2SiMe3)3(THF)2 with the tridentate linked amido−cyclopentadienyl ligands (C5Me4H)SiMe2NHR (R = CH2CH2OMe, CH2CH2NMe2, CH2CH2CH2OMe, CMe2CH2OMe), which contain an additional donor site, results in the cleavage of the silicon−cyclopentadienyl bond and the formation of the tetramethylcyclopentadienyl complexes Y(η5-C5Me4H){N(SiMe2CH2SiMe3)(R)}(CH2SiMe3)(THF)x (x = 0, 1). The dimeric hydrido complexes [Y(η5:η1-C5Me4SiMe2NCMe2R)(THF)(μ-H)]2 are prepared in good yields by hydrogenolysis of the corresponding alkyl complexes. Variable-temperature 1H, 13C, 29Si, and 89Y NMR spectroscopic data sh...