| Autor: |
Reddy, Mandadhi Guruprasad, Lobo, Nitin P., Narasimhaswamy, T. |
| Předmět: |
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| Zdroj: |
Liquid Crystals; May2016, Vol. 43 Issue 7, p896-909, 14p |
| Abstrakt: |
A homologous series of rod-like molecules with three phenyl rings in the core and terminal alkoxy chains are synthesised from mesogenic two-ring aldehyde by coupling with non-mesogenic 4-alkoxy anilines. The mesophase properties are evaluated with hot-stage optical polarising microscopy and differential scanning calorimetry, and accordingly, all the molecules exhibited enantiotropic nematic and smectic C phases along with monotropic low-temperature smectic phases. For a representative homologue, the existence of smectic C phase is further confirmed by noticing a sharp reflection at small angle region in powder X-ray diffraction which varies with change in temperature. The main focus of the investigation, however, is the clear demonstration of chemical shift assignment of static13C NMR of a representative three-phenyl ring mesogen in smectic C phase. In this novel approach, the static13C NMR spectral data of synthetic mesogenic intermediate namely two-ring aldehyde are utilised for the chemical shift assignment of three-ring mesogens. Further, the orientational order parameter of two-ring aldehyde in smectic A and three-ring mesogen in smectic C phase is carried out by measuring the13C-1H dipolar couplings by 2D separated local field spectroscopy. [ABSTRACT FROM PUBLISHER] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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