✦ LIBER ✦
Determination of the methyl group rotation energy barrier in some substituted tricyclo [3.1.0.02,6]hexanes by carbon-13 spinlattice relaxation
✍ Scribed by W. A. Mellink; R. Kaptein
- Publisher
- John Wiley and Sons
- Year
- 1980
- Tongue
- English
- Weight
- 256 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
Abstract
The resonances in the ^13^C NMR spectra of 1,2,5,6‐tetramethyl‐3,4‐dimethylenetricyclo[3.1.0.0^2,6^]hexane and the corresponding enone and dione have been assigned. The rotation energy barriers of the methyl groups have been determined from ^13^C spin‐lattice relaxation time measurements; barriers of 6.7–10.9 kJ mol^−1^ have been found. Since X‐ray data have shown that the skeleton bonds are bent away from the CCH~3~ axis by angles of over 120°, only minor interactions occur between adjacent methyl groups. Therefore, these barriers are mainly governed by interactions with the CC skeleton bonds.