Three series with total number of twenty-four new compounds which are symmetrical and asymmetrical triphenylene discotic liquid crystals with two different kinds of peripheral chains, C₁₈H₆(OR)₃(OCH₂COOEt)₃, C₁₈H₆(OR)₃(OCH₂COOBu)₃ and C₁₈H₆(OR)₃(OCH₂CONHBu)₃, (R＝C₅H₁₁, C₆H₁₃, C₇H₁₅, C₈H₁₇) were synthesized. The purification was carried out with column chromatography and structure characterization of these compounds was carried out with ¹H NMR, IR and elementary analysis. The thermal gravimetry analysis results showed that all these compounds have good thermal stability up to 300 ℃. Their thermotropic liquid crystal properties were studied with polarizing optical microscopy and differential scanning calorimetry. The results showed that, for compounds C₁₈H₆(OR)₃(OCH₂COOEt)₃, the asymmetrical compounds have lower melting and higher clearing points than that of their corresponding symmetrical compounds, thus asymmetrical compounds have wider mesophase temperature ranges. For the triphenylene derivatives containing amide group with structure of C₁₈H₆(OR)₃(OCH₂CONHBu)₃, the symmetrical compounds exhibit higher clearing points and more ordered hexagonal columnar mesophase than their corresponding asymmetrical ones. For comparison of symmetrical and asymmetrical compounds C₁₈H₆(OR)₃(OCH₂CONHBu)₃ and C₁₈H₆(OR)₃(OCH₂COOBu)₃, the formers have not only higher melting and clearing points but also richer columnar phases than the latter ones due to intermolecular hydrogen bonding.

Key words: triphenylene, discotic liquid crystal, columnar mesophase, intermolecular hydrogen bonding, supramolecular, anchorage of columnar mesophase