Simple Trends in NMR Spectra of Vinyl Polymers: The 1H NMR Spectrum of Poly(propylene)

Abstract

AbstractSummary: The tacticity spreading of chemical shifts in the proton NMR spectrum of poly(propylene) in solution has been analyzed first qualitatively, taking advantage of known trends in both proton chemical shift and conformational statistics of vinyl polymers as summarized in the telephone rule, and then quantitatively using ab initio computations, empirical additivity schemes of proton chemical shifts, and conformational averages according to models of different rotational isomeric states. The very good results obtained, both qualitatively and quantitatively, stem from the relatively easy parametrization of proton chemical shift and establish a successful application of the telephone rule, also for proton NMR spectra.Anti and syn labeling of methylene hydrogens in m and r diads.magnified imageAnti and syn labeling of methylene hydrogens in m and r diads.