Fluorine-19 FT–NMR studies of CF3-containing systems dissolved in smectic liquid crystal solutions

Abstract

Articles you may be interested inThe dynamical behavior of a small probe molecule dissolved in a nematic liquid crystal studied by NMR J. Chem. Phys. 78, 1712 (1983; 10.1063/1.444956 19F shielding anisotropies of the fluoromethanes obtained from NMR studies in a smectic liquid crystal solution J. Chem. Phys. 66, 989 (1977); 10.1063/1.434010 Deuterium magnetic resonance study of a smectic liquid crystalThe fluorine-19 shielding anisotropies of CFJCI, CF 3 Br, CFJI, and CF J CCl 3 have been determined from analyses of fluorine NMR spectra in partially ordered smectic liquid crystal solutions. The high degree of orientation and increased solubility produced in the smectic phase leads to measurements of 0" II -0" 1 for each of these systems to relatively high accuracy. The anisotropies obtained for the trifluorohalomethanes are found to increase in the order: CF 3 Cl, -13.4±O.5 ppm; CFJBr, 2.7±O.3 ppm; CFJI, 16.8±O.2 ppm. The quantity 0"11 is approximately constant for each of the CF 3 X molecules studied. This feature permits an estimate of the shielding and spin-rotation constants of CF •.

Cyclotetraphosphanes: geometry, 1J(PP) nuclear magnetic resonance coupling constants, and phosphorus chemical shift anisotropy. A nuclear magnetic resonance study in liquid crystals

“…It has been shown that this method of temperature variation can lead to serious discrepancies when compared with the results obtained by use of the smectic phase in which the ordering parameter 5ZZ can be changed by means of a sample orientation change instead of a temperature change. 43 However, in the present study, it has been checked on one compound (PtBu)4 that the value obtained by use of a smectic phase is in good agreement with the one obtained by use of a nematic phase (145 vs. 167 ppm).…”