Ab initio studies on mimics of substituted poly(thionylphosphazenes)

Ab initio quantum chemical calculations have been performed on model compounds of polythionylphosphazenes. The calculations were carried out using the Gaussian 90 program package employing the 3 - 21G* and the 6-31G* basic sets. The stable conformations of the mimic substituted with hydrogen, chlorine, fluorine and methyl groups were determined. The resulting molecular structures show a clear distinction between bond lengths of single and double bonds in the main chain. The S-N-P and P-N-P bond angles vary slightly depending on the choice of substituents. The two different substituents on sulfur lead to a distortion of the cis - trans conformation, and therefore suggest a non-planar molecular conformation.