Molecular dynamics of polystyrene model molecules. Conformational energy and ultrasonic relaxation of 2,4,6-triphenylheptane
- 1 January 1978
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics
- Vol. 74, 445-455
- https://doi.org/10.1039/f29787400445
Abstract
Conformational energies have been calculated for isotactic, syndiotactic and heterotactic 2,4,6-triphenylheptane, giving the most likely states and the conformational paths between them. The ultrasonic attenuation of these compounds has been investigated as a function of temperature and frequency. A single relaxation is observed for isotactic and syndiotactic isomers and has been assigned to isomerism between the helix tg+tg+(or g–tg–t) and the transition form g–ttg+ for the isotactic, and between tttt and ttg+g+(or g–g–tt) conformations for the syndiotactic isomer. Two relaxation processes were needed for the heterotactic isomer, each involving one part of the molecule; the rotational isomerism of the meso diad is between g–ttt (or tg+tt) and tttt conformations, while the racemic diad involves a relaxation between g–ttt and g–tg+g+ conformations.Keywords
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