Stereochemistry in PVC Oligomers Revealed by Theoretical Investigation on 1H and 13C NMR Chemical Shifts

摘要

DFT calculations of 1H and 13C chemical shifts are used to interpret the NMR spectra of PVC oligomers and to unravel the presence of defects.First,simulations are carried out and compared to experimental data on known species in order to "calibrate" the theoretical approach and assess the electron correlation,relativistic,and surrounding effects.Then,PVC chains are investigated by considering their many conformations in order to highlight the NMR signatures of regular chains of different tacticities as well as of chains containing branches and unsaturations.