-
Views
-
Cite
Cite
Gaku Yamamoto, Michinori Oki, Restricted Rotation Involving the Tetrahedral Carbon. LX. peri-Substituent Effect on the Rotational Barrier of the 9-Methyl Group in Several Triptycene Derivatives, Bulletin of the Chemical Society of Japan, Volume 63, Issue 12, December 1990, Pages 3550–3559, https://doi.org/10.1246/bcsj.63.3550
- Share Icon Share
Abstract
Dynamic 1H NMR study was made on several 1-substituted 8,13-dichloro-9-methyltriptycenes and 8-chloro-13-fluoro-9-methyltriptycenes to examine the effect of the peri-substituents on the rotational barrier of the 9-methyl group. The rotational barrier height increases in the expected order as the 1-hydrogen is replaced by a bulkier group up to CH3, but shows a very low value when a t-butyl group is introduced into 1-position to show that destabilization of the ground state by the bulky t-butyl group exceeds that of the transition state for rotation.