Theoretical potential scans and vibrational spectra of vinyl selenonyl halides CH₂=CH-SeO₂X (X is F, Cl and Br)

The structure and conformational stability of vinyl selenonyl fluoride, chloride and bromide CH₂=CH-SeO₂X (X is F, Cl and Br) were investigated using density functional B3LYP/6-311+G** and ab initio MP2/6-311+G** calculations. From the calculations the molecules were predicted to exist only in the non-planar gauche conformation with the vinyl C=C group almost eclipsing one of the selenonyl Se=O bonds as a result of conjugation between the two moieties. Single-minimum potential scans were calculated at the DFT level for the molecules. The vibrational frequencies were computed using B3LYP/6-311+G**. Normal coordinate calculations were then carried out and potential energy distributions were calculated for the three molecules in the gauche conformation.