Synthesis and characterization of η5-tetramethylcyclopentadienyl hydrido-and -chloro-silyl-η1 -amido zirconium complexes

The silylated tetramethylcyclopentadienes C5Me4(SiMeCl2)(SiMe3) (1) and C5Me4H(SiMeHCl) (3) were isolated by reaction of their corresponding trimethylsilyltetramethylcyclopentadienyl and tetramethylcyclopentadienyl lithium salts with SiMeCl3 and SiMeHCl2, respectively. Reaction of a toluene suspension of ZrCl4 with one equivalent of 1 afforded the monocyclopentadienyl zirconium complex [Zr(h5 -C5Me4SiMeCl2)Cl3] (2). Reaction of 3 with NH2 t Bu gave C5Me4H[SiMeH(NHt Bu)] (4) which was further metallated to give Li2[C5Me4SiMeH(Nt Bu)] (5), used to prepare the silyl-h1 -amido zirconium derivative [Zr(h5 -C5Me4SiMeH-h1 - Nt Bu)Cl2] (6) by reaction with ZrCl4(THF)2. Chlorination of 6 with BCl3 afforded [Zr(h5 -C5Me4SiMeCl-h1 -Nt Bu)Cl2] (12). Alkylation and amidation of 6 and 12 provided the corresponding disubstituted [Zr(h5 -C5Me4SiMeH-h1 -Nt Bu)R2] (R /Me 7, CH2Ph 8, NMe2 9) and [Zr(h5 -C5Me4SiMeCl-h1 -Nt Bu)Me2] (13) and monosubstituted [Zr(h5 -C5Me4SiMeH-h1 -Nt Bu)ClR] (R / C6F5 10, N(SiMe3)2 11) and [Zr(h5 -C5Me4SiMeCl-h1 -Nt Bu)Cl{N(SiMe3)2}] (14). All of the new compounds reported were characterized by elemental analyses and NMR spectroscopy.We thank Ministerio de Ciencia y Tecnología for support of this work (Project MCyT-MAT2001-1309 and predoctoral fellowship to A.B.V