Paper
20 July 2004 Smectogenic C* 2,6-bis-arylidene derivatives of 3(R)-ethylcyclohexanone exhibiting inversion of spontaneous polarization sign
Nikolay S. Pivnenko, Alexander I. Krivoshey, Lidiya A. Kutulya, V. I. Musatov
Author Affiliations +
Proceedings Volume 5507, XVI International Conference on Spectroscopy of Molecules and Crystals; (2004) https://doi.org/10.1117/12.569834
Event: XVI International Conference on Spectroscopy of Molecules and Crystals, 2003, Sevastopol, Ukraine
Abstract
Temperature measurements of 1H NMR spectra in (CD3)2S0 solutions have been carried out for 2,6-bis-[4-(4-methoxybenzoyloxy)-benzylidene]-3(R)-methylcyclohexanone as a model compound for smectogenic C* homologues demonstrating an inversion of the spontaneous polarization sign to clarify an opportunity of configurational and conformational changes with the temperature rise as origins of this effect. In the temperature ranges 30 - 110°C, spectral evidences in favor of the possible temperature-induced E→Z isomerization were not revealed. At the same time, changes found in vicinal spin-spin couplings in combination with data of molecular simulation by the semi-empirical PM3 method allowed to determine an appreciable displacement of the chair ↔ twist-boat conformational equilibrium for the cyclohexanone ring with temperature in direction of the increase by 15 % of the fraction of twist-forms. However, it was demonstrated with molecular simulation this process cannot result in a substantial alteration in the value and direction of the dipole moment. This concerns also intra-molecular rotation in the exocyclic fragments of isolated molecules resulting in conformers with quite different dipole moments, but with the very close energies and populations in the whole temperature interval studied. The single factor responsible for the inversion of the spontaneous polarization sign can be surmised to be changes in conformational energetics.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Nikolay S. Pivnenko, Alexander I. Krivoshey, Lidiya A. Kutulya, and V. I. Musatov "Smectogenic C* 2,6-bis-arylidene derivatives of 3(R)-ethylcyclohexanone exhibiting inversion of spontaneous polarization sign", Proc. SPIE 5507, XVI International Conference on Spectroscopy of Molecules and Crystals, (20 July 2004); https://doi.org/10.1117/12.569834
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KEYWORDS
Polarization

Temperature metrology

Molecules

Spectroscopy

Modeling

Molecular spectroscopy

Binary data

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