Novel cyclopentadienyl silanes and disilanes: synthesis, structure and gas-phase pyrolysis

The new chloro(cyclopentadienyl)silanes Cp′SiH_yCl_3−y (Cp′=Me₄EtC₅, y=1: 1; Cp′=Me₄C₅H, y=1: 2; y=0: 3; Cp′=Me₃C₅H₂, y=1: 4 and pentachloro(cyclopentadienyl)disilanes Cp′Si₂Cl₅ (Cp′=Me₅C₅ 5, Me₄EtC₅ 6, Me₄C₅H 7, Me₃C₅H₂ 8, Me₃SiC₅H₄ 9) are synthesized in good yields via metathesis reactions. Treatment of 1–9 with LiAlH₄ leads under Cl–H exchange to the hydridosilyl compounds Cp′SiH₃ (Cp′=Me₄EtC₅ 10, Me₄C₅H 11, Me₃C₅H₂ 12) and to the hydridodisilanyl compounds Cp′Si₂H₅ (Cp′=Me₅C₅ 13, Me₄EtC₅ 14, Me₄C₅H 15, Me₃C₅H₂ 16, Me₃SiC₅H₄ 17). Complexes 1–17 are characterized by ¹H, ¹³C, and ²⁹Si-NMR spectroscopy, IR spectroscopy, mass spectrometry and CH-analysis. The structures of 6, 7 and 9 are determined by single-crystal X-ray diffraction analysis. Pyrolysis studies of the cyclopentadienylsilanes 10–12 and disilanes 13–17 show their suitability as precursors in the MOCVD process.