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In this work, two novel triphenylene−ammonium−ammonium−triphenylene diads were synthesised. The effect of the peripheral chain length around triphenylene and the length of the linker connecting triphenylene with an ammonium moiety on the liquid crystalline behaviour was studied. The molecular structures were verified using proton and carbon nuclear magnetic resonance, mass spectrometry and elemental analysis. The liquid crystalline properties of these compounds were determined by polarising optical microscopy, differential scanning calorimetry and X-ray diffraction studies. These triphenylene−ammonium-based gemini dimers with tetrafluoroborate as the counter ion were found to exhibit liquid crystalline behaviour with a hexagonal columnar phase morphology. [ABSTRACT FROM AUTHOR]

Abstract: Six novel gemini imidazolium salts tethered with hexaalkoxytriphenylene moieties were prepared by quaternization of imidazole nitrogen with ω-bromo-substituted triphenylene derivatives. Their chemical structures were examined by 1H NMR, IR, UV, MS, and elemental analyses. The mesomorphic properties of these discotic dimeric salts were investigated by polarizing optical microscopy, differential scanning calorimetry, and X-ray diffraction studies. These triphenylene-imidazole-based gemini dimers with bromide as counter ion were found to exhibit liquid crystalline behavior over a wide temperature range and display ionic conductivity in the range of 10−6 to 10−5 S/m. These materials tend to form monolayer at the air–water interface. [Copyright &y& Elsevier]