A joined theoretical-experimental investigation on the 1H and 13C NMR signatures of defects in poly(vinyl chloride).

1H and 13C chemical shifts of PVC chains have been evaluated using quantum chemistry methods in order to evidence and interpret the NMR signatures of chains bearing unsaturated and branched defects. The geometrical structures of the stable conformers have been determined using molecular mechanics and the OPLS force field and then density functional theory with the B3LYP functional and the 6-311G(d) basis set. The nuclear shielding tensor has been calculated at the coupled-perturbed Kohn-Sham level (B3LYP exchange-correlation functional) using the 6-311+G(2d,p) basis set.

Highly Selective Route for Producing Unsymmetrically Substituted Monomers toward Synthesis of Conjugated Polymers Derived from Poly(p-phenylene vinylene).

A new convenient route for producing unsymmetrically substituted sulfinyl monomers of precursor polymers toward poly(p-phenylene vinylene) is described. Upon treating a symmetrical bissulfonium salt with a thiolate anion, an unexpected high selectivity for the monosubstituted thioethers (90%) is obtained. Optimization of the reaction conditions showed that the stoichiometry of the reactants in this reaction is important to ensure the high selectivity and to prevent unwanted side reactions.