Molecular structure of phenylsilane: A study by gas-phase electron diffraction and ab initio molecular orbital calculations

Gustavo Portalone, Fabio Ramondo, Aldo Domenicano, István Hargittai

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16 Citations (Scopus)

Abstract

The molecular structure of phenylsilane has been determined accurately by gas-phase electron diffraction and ab initio MO calculations at the MP2(f.c.)/6-31G* level. The calculations indicate that the perpendicular conformation of the molecule, with a Si-H bond in a plane orthogonal to the plane of the benzene ring, is the potential energy minimum. The coplanar conformation, with a Si-H bond in the plane of the ring, corresponds to a rotational transition state. However, the difference in energy is very small, 0.13 kJ mol-1, implying free rotation of the substituent at the temperature of the electron diffraction experiment (301 K). Important bond lengths from electron diffraction are: <rg(C-C)>=1.403±0.003 Å, rg(Si-C)=1.870±0.004 Å, and rg(Si-H)=1.497±0.007 Å. The calculations indicate that the Cipso-Cortho bonds are 0.010 Å longer than the other C-C bonds. The internal ring angle at the ipso position is 118.1±0.2° from electron diffraction and 118.0° from calculations. This confirms the more than 40-year old suggestion of a possible angular deformation of the ring in phenylsilane, in an early electron diffraction study by F.A. Keidel, S.H. Bauer, J. Chem. Phys. 25 (1956) 1218.

Original languageEnglish
Pages (from-to)183-190
Number of pages8
JournalJournal of Organometallic Chemistry
Volume560
Issue number1-2
DOIs
Publication statusPublished - Jun 15 1998

Keywords

  • Ab initio MO calculations
  • Gas-phase electron diffraction
  • Molecular structure
  • Phenylsilane
  • Silicon

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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