13C NMR chemical shifts and stereochemical structures in poly(vinyl chloride)

The 13C NMR chemical shifts of triad and tetrad configurations in poly(vinyl chloride) have been calculated by the average excitation energy approximation using the CNDO/2 MO method. On the basis of these calculations, both Inoue's and Carman's assignments for the observations of the triad and tetrad configurations have been examined and the partial discrepancy between them ascribed to the solvent effect. Further, the tacticity dependences of the calculated chemical shifts for triad and tetrad configurations are discussed.