Synthesis and characterization of η 5-tetramethylcyclopentadienyl-hydrido- and -chloro-silyl-η 1-amido zirconium complexes

Abstract

The silylated tetramethylcyclopentadienes C 5Me 4(SiMeCl 2)(SiMe 3) ( 1) and C 5Me 4H(SiMeHCl) ( 3) were isolated by reaction of their corresponding trimethylsilyltetramethylcyclopentadienyl and tetramethylcyclopentadienyl lithium salts with SiMeCl 3 and SiMeHCl 2, respectively. Reaction of a toluene suspension of ZrCl 4 with one equivalent of 1 afforded the monocyclopentadienyl zirconium complex [Zr(η 5-C 5Me 4SiMeCl 2)Cl 3] ( 2). Reaction of 3 with NH 2 t Bu gave C 5Me 4H[SiMeH(NH t Bu)] ( 4) which was further metallated to give Li 2[C 5Me 4SiMeH(N t Bu)] ( 5), used to prepare the silyl-η 1-amido zirconium derivative [Zr(η 5-C 5Me 4SiMeH-η 1-N t Bu)Cl 2] ( 6) by reaction with ZrCl 4(THF) 2. Chlorination of 6 with BCl 3 afforded [Zr(η 5-C 5Me 4SiMeCl-η 1-N t Bu)Cl 2] ( 12). Alkylation and amidation of 6 and 12 provided the corresponding disubstituted [Zr(η 5-C 5Me 4SiMeH-η 1-N t Bu)R 2] (R=Me 7, CH 2Ph 8, NMe 2 9) and [Zr(η 5-C 5Me 4SiMeCl-η 1-N t Bu)Me 2] ( 13) and monosubstituted [Zr(η 5-C 5Me 4SiMeH-η 1-N t Bu)ClR] (R=C 6F 5 10, N(SiMe 3) 2 11) and [Zr(η 5-C 5Me 4SiMeCl-η 1-N t Bu)Cl{N(SiMe 3) 2}] ( 14). All of the new compounds reported were characterized by elemental analyses and NMR spectroscopy.