Preliminary communication Properties of nonlinear supramolecular liquid crystals containing thiophenedicarboxylic acids

Abstract

Novel mesogenic supramolecules have been constructed from the 2 :1 molar ratio of trans 4-alkoxy-4-stilbazoles CnPS (1) complexed with 2,5-thiophenedicarboxylic acid THDA (4) to form the kinked hydrogen-bonded (H-bonded) complexes (CnPS)-THDA. The analogous H-bonded complexes (CnPP)2-THDA consisting of the 2:1 molar ratio of 4-alkoxypyridines CnPP (2) and THDA (4) are also compared. In contrast to linear complexes (CnPS)2-TA prepared from the 2 :1 molar ratio of CnPS (1) and terephthalic acid TA (5), supramolecular liquid crystals with kinked molecular structures (CnPS)2-THDA are generated by introducing the thiophene unit into the H-bonded complexes. In addition, the chiral complex (C5*PS)2-THDA composed of an optically active proton acceptor (S)-(-)-4-(2-methylbutoxy)-4-stilbazole C5*PS (3) and THDA (4) (2 :1 molar ratio) is reported. Significantly, the first thiophene based supramolecular liquid crystals have been constructed in this study, and the mesogenic properties of the supramolecules can be easily adjusted not only by the nonlinear shape of the thiophene unit but also by the dipole moment derived from the lone-pair electrons of the sulphur hetero-atom.