Syntheses and mesomorphic properties of novel triphenylene liquid crystals with 15-crown-5 unit as side-chain

Two novel triphenylene liquid crystals with 15-crown-5 unit as side-chain 4a and 4b were designed and synthesised by simple procedures in ideal yields. Their structures were confirmed by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (1H NMR), electrospray ionization mass spectrometry (ESI-MS) and elemental analysis. Their liquid-crystalline behaviours before and after complexation with metallic salts were studied by differential scanning calorimetry, polarising optical microscopy and X-ray diffraction. Neat compounds 4a and 4b show mesophase with triphenylene column, while complexes of 4a and 4b with metallic salts exhibit no mesophase but higher melting point.