Catalytic dehydrocoupling of PhSiH 3 with bimetallic Ti and Zr complexes

Abstract

Bimetallic titanium and zirconium complexes with bridges (X) between Cp ligands were compared to Cp 2MCl 2 as catalysts in the presence of nBuLi for the dehydrocoupling of PhSiH 3 to polyphenylsilane. The monobridged bimetallic complexes developed were of the composition [μ-X(C 5H 4) 2][CpMCl 2] 2 with XMe 2Si (MTi, Zr), Me 2SiCH 2SiMe 2 (MTi) and Me 2SiCH 2CH 2SiMe 2 (MTi, Zr). The dibridged bimetallic complexes examined were of the type [μ,μ-(Me 2Si) 2(C 5H 3) 2][Cp′TiCl 2] 2 (Cp′  Cp, trans isomer, Cp′ = Cp *, trans and cis isomers). There was not a significant difference in the molecular weight of the polysilane produced from Cp 2TiCl 2 and the bimetallic titanium complexes after 48 h of reaction. However, the polysilane which was generated from the bimetallic complex [μ-(Me 2Si)(C 5H 4) 2][CpZrCl 2] 2 was approximately twice the molecular weight compared to that obtained from Cp 2ZrCl 2. The structure of the bimetallic complex [μ-(Me 2SiCH 2CH 2SiMe 2)(C 5H 4) 2][CpZrCl 2] 2 was determined by X-ray diffraction (monoclinic, P2 1/ n, a = 8.7297(3) A ̊ , b = 6.7890(2) A ̊ , c = 24.9343(7) A ̊ , β = 93.7850(10)°, Z = 2).