抄録
The half-sandwich mono- and dialkyl rare earth metal complexes are prepared either by the alkane elimination reactions or by the metathetical reactions. Half-sandwich scandium alkyl complex bearing the silylene-linked cyclopentadienyl-amido ligand can serve as a unique catalyst for the ortho-selective C-H silylation of various alkoxy-substituted benzene derivatives without requirement for a hydrogen acceptor to achieve high conversion. The reaction of the dialkyl complexes with an equivalent of a borate compound such as [Ph3C][B(C6F5)4] generates easily the corresponding cationic monoalkyl species, which serve as excellent catalysts for the polymerization and copolymerization of a variety of olefins to yield a new family of polymer materials that show novel properties but are difficult to prepare by other catalysts. Mechanistic aspects of these catalytic processes are also described.
