Synthesis and solid-state polymerization of diacetylene derivatives with an N-carbazolylphenyl Group

Four diacetylene derivatives with an N-carbazolylphenyl group as a donor moiety have been synthesized and subsequently characterized. These diacetylene derivatives undergo solid-state polymerization via UV irradiation, although these compounds have relatively large π-conjugated aromatic groups. The polymerization behaviors of these derivatives were confirmed by distinct absorption bands for polydiacetylenes. The reactive process is strongly influenced by the slightly differing side groups. Single crystal growth of the two compounds was successful and their crystal structure analyses revealed large differences in the molecular conformations and intermolecular geometries caused by a methylene unit. The HOMO population of the monomers is predominantly expressed in the phenyl carbazole unit, while each polymer showed differing HOMO energies with some polymers exhibiting high-lying HOMO levels.