Density functional theory investigation of the stereochemistry effects on 1H and 13C NMR chemical shifts of poly(vinyl chloride) oligomers

Using density functional theory approaches, 1H and 13C chemical shifts of stereoisomers of poly(vinyl chloride) oligomers have been simulated and compared to experimental data. The theoretical simulations employ linear relationships between experimental and theoretical chemical shifts of small compounds containing H, C, and Cl atoms in order to correct the estimates for missing electron correlation and surrounding effects. Simulations for triads and tetrads are shown to reproduce the experimental trends among the stereoisomers and also, in most cases, to provide good quantitative agreement with the experimental data. The variations of chemical shifts among the different stereoisomers are correlated to the various conformations and their relative weights.