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(η5-C5Me4SiMeCl2)Cl3] (2). Reaction of 3 with NH2tBu gave C5Me4H[SiMeH(NHtBu)] (4) which was further metallated to give Li2[C5Me4SiMeH(NtBu)] (5), used to prepare the silyl-η1-amido zirconium derivative [Zr(η5-C5Me4SiMeH-η1-NtBu)Cl2] (6) by reaction with ZrCl4(THF)2. Chlorination of 6 with BCl3 afforded [Zr(η5-C5Me4SiMeCl-η1-NtBu)Cl2] (12). Alkylation and amidation of 6 and 12 provided the corresponding disubstituted [Zr(η5-C5Me4SiMeH-η1-NtBu)R2] (R=Me 7, CH2Ph 8, NMe29) and [Zr(η5-C5Me4SiMeCl-η1-NtBu)Me2] (13) and monosubstituted [Zr(η5-C5Me4SiMeH-η1-NtBu)ClR] (R=C6F510, N(SiMe3)211) and [Zr(η5-C5Me4SiMeCl-η1-NtBu)Cl{N(SiMe3)2}] (14). All of the new compounds reported were characterized by elemental analyses and NMR spectroscopy.