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A series of triphenylene discotic liquid crystals with amido-based alkyl chains in different lengths were synthesized and characterized. The liquid crystal properties were studied with differential scanning calorimetry and polarizing optical microscopy. The influences of amide alkyl chain lengths on the mesomorphism were discussed. Based on the results, we concluded that the triphenylene discogens with an amido-based alkyl chain could form intermolecular hydrogen bonds inside their columnar stacks, and hence, exhibit higher melting and clearing points, and wider mesophase ranges. [ABSTRACT FROM AUTHOR]

Intermolecular hydrogen bond is an efficient way to anchor columnar assembly of discotic liquid crystals, and would result in more ordered columnar mesphase and faster charged carrier mobility. In this report, a series of peripheral functionalized triphenylene derivatives, C18H6(OC6H13)4(OCH2CONHR)2, which contains amide groups at the 2,7-positions, have been synthesized. The polarized optical microscopy (POM) and differential scanning calorimetry (DSC) results showed that these compounds exhibit hexagonal columnar mesophases. The triphenylene derivatives gelate in the solution of octane, petroleum ether, cyclohexane and p-xylene and form stable organic gels. The xerogels formed from organic solvents were analyzed by scanning electron microscope (SEM) and showed fiber-like or sponge-like morphology. It is demonstrated that intermolecular hydrogen bonds stabilize the columnar molecular organization and assembly in mesomorphic state and organic gel. [ABSTRACT FROM AUTHOR]

Tuning hydrogen-bonding of discotic liquid crystal can result in more ordered columnar mesophases and higher charge carrier mobility materials. In this paper, triphenylene derivatives with one, two and three amide groups with structure of C18H6(OR)5(OCH2CONHBu), C18H6(OC5H11)4(OCH2CONHBu)2 and symmetrical and asymmetrical C18H6(OR)3(OCH2CONHBu)3 (R = CnH2n+1, n = 4-9) respectively were designed and synthesized. The results showed that each intra-columnar H-bond forming amide (-CONH-) group caused an average increase of 22°C in clearing point from the non-H-bonding ester group (-COO-) triphenylene analogous. This was the first quantitative result of H-bonding on the stabilization of columnar mesophase. [ABSTRACT FROM AUTHOR]