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A novel approach to ambipolar semiconductors based on hydrogen-bonded complexes between a star-shaped tris(triazolyl)triazine and triphenylene-containing benzoic acids is described. The formation of 1:3 supramolecular complexes was evidenced by different techniques. Mesogenic driving forces played a decisive role in the formation of the hydrogen-bonded complexes in the bulk. All of the complexes formed by nonmesogenic components gave rise to hexagonal columnar (Col) liquid crystal phases, which are stable at room temperature. In all cases, X-ray diffraction experiments supported by electron density distribution maps confirmed triphenylene/tris(triazolyl)triazine segregation into hexagonal sublattices and lattices, respectively, as well as remarkable intracolumnar order. These highly ordered nanostructures, obtained by the combined supramolecular H-bond/columnar liquid crystal approach, yielded donor/acceptor coaxial organization that is promising for the formation of ambipolar organic semiconductors with high mobilities, as indicated by charge transport measurements.

We present a structural study of the mesophases of three achiral bent-core compounds with azo and azoxy bonds. The study is based on textures observation and small-angle X-ray diffraction. It is found that the materials exhibit columnar and tilted smectic mesophases. Optical second-harmonic generation measurements are performed on aligned samples of one of the compounds, and the whole second-order susceptibility tensor is determined. Finally, some simple aspects of the photoisomerization of the materials are examined.