| Summary: | 碩士 === 國立中央大學 === 化學學系 === 101 === Series I
A novel system of symmetric dimers containing quinoxaline units has been synthesized and their mesomorphic behavior investigated. All compounds were characterized by 1H, 13C-NMR spectroscopy and the mesomorphic behavior of these compounds investigated by polarized optical microscopy, differential scanning calorimetry and powder x-ray diffraction. The formation of mesophases was found to be sensitive to the number of carbon length of the side chains and/or the spacer. The results indicated that compound 1a, 1c and 1d exhibited hexagonal columnar phases. Packing studies indicated that a single molecule was required to generate a disc-like correlated structure in the columnar phases. The UV and PL spectra were also studied for their light-emitting properties.
Series II
A new system of 1,3,4-oxa(thia)diazoles contaning quinoxaline exhibiting mesomorphic properties was synthesized and their mesomorphic properties examined. These molecules exhibited hexagonal columnar phases. A change of alkoxy chains and oxygen/sulfur atoms incorporated was amied to their difference or effect on the formation of mesophases. The formation of columnar phases was strongly sensitive to the central heteroatoms and/or their positions incorporated. Packing studies indicated that two molecules laid side-by-side to required to generate a more disc-like correlated structure in the columnar phases. However, these materials show great potential for electronic devices.
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