1,2-Di-tert-butyltetrafluorodisilane, Bu^tSiF₂SiF₂Bu^t: vibrational spectra and molecular structure in the gas phase by electron diffraction and ab initio calculations

Abstract

The molecular structure of 1,2-di-tert-butyltetrafluorodisilane, Bu^tSiF₂SiF₂Bu^t, has been determined in the gas phase by electron diffraction (GED) and ab initio molecular orbital calculations. Together with infrared and Raman studies, GED shows that only a single conformer (anti, C_2h symmetry) is present in the gas phase. From normal coordinate analysis, the Si–Si stretching force constant is 179 N m^-1, within the range previously observed for other related compounds. Important structural parameters (r_a) are: Si–Si 234.6(6), Si–C 187.2(3), Si–F 160.0(2), C–C 153.7(3), C–H 113.5(2) pm, Si–Si–C 114.6(7), Si–Si–F 108.7(3) and F–Si–F 107(2)°. This geometry is supported by theoretical predictions obtained at the 6-31G*/SCF level.

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