Molecular crystals and liquid crystals · 1987 · 14 citations · 5 references
Natural SciencesChemistryPhysicsCondensed Matter PhysicsSolid-state ChemistrySpectroscopyElectron Spin Resonance SpectroscopyMagnetic Resonance SpectroscopyPhase TransitionsRelaxation MechanismsCarbon-13 Nuclear Magnetic ResonanceNuclear Magnetic Resonance RelaxationNuclear Magnetic Resonance RelaxometryRelaxation Time MeasurementsRelaxation TimesSpin RelaxationSpin-lattice RelaxationTemperature Dependence
Abstract The carbon-13 chemical shifts and spin-lattice relaxation times were obtained for all the resolved resonances in the isotropic and nematic phases of 5CB, 6CB, and 7CB. NOE measurements were also obtained for the isotropic phases of 5CB, 6CB, 7CB, and 8CB. These results and those previously obtained by us for 8CB and for the isotropic phase of 5CB, demonstrate that even-odd effects occur for the carbon-13 spin-lattice relaxation times which cannot be explained by the differences in the nematic-isotropic transition temperatures. It is observed that the temperature dependence of the NOE's is significantly different for the protonated and unprotonated aromatic carbons.
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