Syntheses and Photonic Properties of Indolocarbazole Derivatives

Abstract

In this study, the syntheses of indolo[3,2-b]carbazole (INC) derivatives have been investigated, which possessed the planer and conjugated structure and showed the strong blue fluorescence by the irradiation of UV light. In order to improve the solubility of INC, N-alkylated INC derivatives were prepared by the reaction of INC with NaH followed by the addition of alkyl halides, the carbon numbers of which were C₁ - C₁₀. The obtained alkylated INCs were soluble in some solvents, and the unique thermal properties were observed for the alkylated INCs with a long alkyl chain, which became amorphous after melting and showed the mesomorphic-like transitions. According to the fluorescence spectroscopy, these alkylated INC derivatives exhibited the strong emission, the quantum yield of which was about 0.50. On the other hand, the INC derivative containing an octyl group and a p-vinylbenzyl group at N-positions was prepared as a monomer compound to obtain polystyrene-type polymer with INC moiety by a radical polymerization. It was found that the polymer was a glassy polymer and the coating film was easily prepared. In addition, the obtained polymer exhibited a high thermal stability, which maintained the high emission property of INC moiety.