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Anionic polymerization of optically active oxiranes. Analysis of carbon NMR spectra
Author(s) -
Haubenstock Howard,
Yu WeiHong,
Odian George,
Wang Hsin
Publication year - 1998
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/(sici)1521-3935(19981101)199:11<2465::aid-macp2465>3.0.co;2-m
Subject(s) - chemistry , polymerization , carbon 13 nmr , polymer chemistry , anionic addition polymerization , nmr spectra database , polymer , spectral line , organic chemistry , physics , astronomy
The optically active epoxides (2 S ,3 S )‐ and (2 R ,3 S )‐3,4‐epoxy‐1,2‐ O ‐isopropylidene‐1,2‐diols 1 and 2 were synthesized and anionically polymerized with potassium tert ‐butoxide as initiator. Soluble poly‐ 1 's with low polydispersities ( M w / M n = 1.2 – 1.3) and medium molecular weights ( M n = 2000–5000) were obtained. Poly‐ 2 was insoluble in common organic solvents but soluble in hot 2,2,2‐trifluoroethanol. Main‐chain peaks in the 13 C NMR spectrum of poly‐ 1 were fully assigned using a combination of NMR pulse techniques. End‐group peak assignments were made by controlling the type of initiation and by consideration of 13 C NMR spin‐lattice relaxation times.