Molecular structure of divinyl sulphone as studied by electron diffraction, vibrationai spectroscopy, and semiempirical CNDO/2 molecular-orbital calculations

Abstract

An electron-diffraction structure analysis has yielded the following bond lengths (r_a) for the title compound: SO 1.438(3), S–C 1.769(4), CC 1.332(4), and C–H 1.118(6)Å. Of the bond angles, the following two are reliablydetermined: OSO 119.5(12) and S–CC121.5(3)°. CNDO/2 molecular-orbital calculations indicatethe coexistence of three conformers. At least two, possibly more, conformers are present in the vapour according to the electron-diffraction data, which also indicate that the CC bonds tend to eclipse the other bonds. Comparison of a number of bands in the i.r. and Raman spectra for different states of the compound shows the coexistence of at least two, possibly more, conformers in the liquid and in the supercooled liquid, while there is only one form in the crystalline phase. The SO bond lengths and stretching frequencies are consistent with empirical relations found for a relatively large series of sulphones.