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Simple Trends in the Methylene and α ‐Substituent Regions of NMR Spectra of Vinyl Polymers
Author(s) -
Monaco Guglielmo,
Viglione Rosario G.
Publication year - 2004
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200400073
Subject(s) - methylene , substituent , vinyl polymer , polymer , chemistry , spectral line , nmr spectra database , carbon 13 nmr , polymer chemistry , chemical shift , computational chemistry , stereochemistry , organic chemistry , physics , polymerization , astronomy
Summary: Chemical shift trends in the methylene and α substituent regions of 13 C NMR spectra of vinyl polymers have been analyzed in terms of a three‐state rotational isomeric states (RIS) model and the γ ‐ gauche effect. In this framework, it has been demonstrated that the three sequencing rules observed for poly(propylene) can also be expected to work for many other vinyl polymers. The first two rules, justified in terms of the conformational perturbability of stereosequences, turn out to be respected by a considerable number of NMR spectra. On the other hand, the same spectral data are in substantial disagreement with the third rule. An explanation is proposed for this breakdown.Sketches of the three conformations expected for rotation on the two prochiral bonds flanking the methine carbon of a vinyl polymer.