Synthesis And Liquid Crystalline Studies On Rod-Like Diimine Compounds And Disc-Shaped Triphenylene Derivatives
| dc.contributor.author | Abdul Rahim, Mursyida | |
| dc.date.accessioned | 2018-01-15T02:26:09Z | |
| dc.date.available | 2018-01-15T02:26:09Z | |
| dc.date.issued | 2017-08 | |
| dc.description.abstract | Four new series comprising two series of rod-like tetramers which are 4,4ā-bis{4-(4-(S)-2-methylbutyloxycarbonylphenyl)phenoxybutyloxy}benzene-1,4-phenoxyalkanediamine and N,Nā-bis{4-((6-ethoxybenzothiazole-2-yl)azenyl)) phenoxyhexyloxy}benzylidene)benzene-1,4-phenoxyalkanediamine and also the other two series of disc-like triphenylene 2,3,6,7,10,11-hexakis{4-((6-ethoxy benzothiazole-2-yl)-azenyl)phenoxyalkyl-oxy}triphenylene and 2,3,6,7,10,11-hexakis{4[(4-alkyloxy-phenylimino)methyl]phenoxybutyloxy}triphenylene are reported. The molecular structure of all four series were elucidated by different spectroscopic techniques which are CHN, mass spectrometry, FT-IR, 1H-NMR, 13C-NMR, 1H-1H COSY, 1H-13C HMQC and 1H-13C HMBC spectroscopy. The investigation of the anisotropic properties was performed by using polarizing optical microscopy, differential scanning calorimetry and X-ray diffraction. The difference between the two tetramer series is the presence of different groups of peripheral unit attached to Schiff base with different central spacer (n=5 to 10). The first series show enantiotropic chiral nematic phase while the second series exhibit enantiotropic nematic phase with high clearing temperature. A significant odd-even effect can be observed in entropy changes for both series. The third series of disc-like oligomer bearing six peripheral units of azobenzene benzothiazole moiety with different spacer length is prepared. Homologues having short spacer (n=5 to 7) exhibit nematic phase only while those having long spacer chain show nematic and smectic C phases. The fourth series of disc-like oligomers belong to a homologous series of Schiff base peripheral units attached to triphenylene core with varying terminal spacer. Investigation on the anisotropic properties shows that members with short spacer show monotropic SmC phase and members with long spacer exhibit enantiotropic SmC phase. Both of these discotic series reveal that the nematic and smectic phase were driven by rod-like peripheral units. The triphenylene core acts only as a linking unit interconnecting the rod-like unit. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/5383 | |
| dc.language.iso | en | en_US |
| dc.publisher | Universiti Sains Malaysia | en_US |
| dc.subject | Studies on rod-like diimine compounds | en_US |
| dc.subject | and disc-shaped triphenylene derivatives | en_US |
| dc.title | Synthesis And Liquid Crystalline Studies On Rod-Like Diimine Compounds And Disc-Shaped Triphenylene Derivatives | en_US |
| dc.type | Thesis | en_US |
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