13C NMR spectra of linear trimers of buta-1,3-diene obtained from the Ziegler–Natta process
✍ Scribed by A. V. Lubnin; I. S. Podkorytov; L. S. Bresler
- Book ID
- 102524868
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 288 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
Abstract
Titanium‐based Ziegler–Natta catalysts for the polymerization of buta‐1,3‐diene give linear trimers of butadiene among other by‐products. A combination of ^1^H and ^13^C NMR, DEPT and 2D‐INADEQUATE gives exhaustive assignments of their ^13^C NMR spectra and affords their structures. All these trimers are dodeca‐2,4,6,10‐tetraenes which have an isolated cis double bond. The internal double bond of the conjugated triad has a trans configuration in each isomer, and the trimers differ only in the outer double bonds. The ^13^C NMR spectra of the timers reveal that the signal position of the carbon involved in the conjugated double bond series is mainly controlled by the configuration of the adjacent double bond and, to a lesser extent, by the geometry of its own double bond. The oligomers studied serve as models for polyacetylene. Some reassignments in the spectra of oligomers of terminal acetylenes are proposed.
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