Highly Asymmetric Coordination in Alkenes: Gas-Phase Structures of trans-1,2-Dichloro-1,2-disilylethene and 1-Bromo-1-silylethene

Citations Over Time

Abstract

The molecular structures of trans-1,2-dichloro-1,2-disilylethene and 1-bromo-1-silylethene have been determined by gas-phase electron diffraction (GED) and ab initio molecular orbital calculations (MP2/6-311G). Both compounds were found to have highly asymmetric coordination around the carbon atoms with [ab initio (r(e))/GED (r(a))] C=C-Cl [117.0/117.0(2) degrees] and C=C-Si [126.2/128.1(1) degrees] in the C(2)(h) structure of trans-1,2-dichloro-1,2-disilylethene and C=C-Br [119.2/120.7(4) degrees] and C=C-Si [125.0/125.0(4) degrees] in the C(s) structure of 1-bromo-1-silylethene. Other important structural parameters for trans-1,2-dichloro-1,2-disilylethene are C=C [135.2/134.5(3) pm], C-Si [189.4/187.9(2) pm], and C-Cl [175.1/174.9(1) pm], and C=C [134.2/133.4(2) pm], C-Si [187.8/187.2(3) pm], and C-Br [191.3/191.0(3) pm] for 1-bromo-1-silylethene. Further ab initio calculations were carried out on CH(2)CRX and trans-(CRX)(2) (R = SiH(3), CH(3), or H; X = H, F, Cl, or Br) to gauge the effects of electron-withdrawing and electron-donating groups on the structures. They reveal some even more distorted structures. The asymmetric appearance of these molecules can largely be accounted for by valence shell electron pair repulsion theory.

Related Papers

• → Comparison of the molecular structures of five benzene derivatives as determined independently by gas-phase electron diffraction in two different laboratories: a perspective(2010)6 cited
• → Looking Back and Ahead: Gas-Phase Electron Diffraction at 75(2005)11 cited
• → 1,1,2-Trichloro-3,3-difluoro-1-propene. Molecular Structure and Conformation as Determined by Gas Phase Electron Diffraction.(1984)4 cited
• → An electron diffraction determination of the molecular structure of trifluorosilylmanganese pentacarbonyl in the gas phase(1975)11 cited
• → Molecular structure of all-trans 1,2,3,4-tetrabromocyclobutane determined by gas-phase electron diffraction(1985)2 cited