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 C 1-C 10. 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 polystyrenetype 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.

Syntheses and properties of copolymers containing indolocarbazole moiety in the side chain

“…In our previous work, we estimated the photoluminescence quantum yields of INC and alkylated INC to be 0.50 and 0.52-0.54, respectively. 30 Therefore, copolymers containing the INC moiety are candidates for photonic or electronic materials in the emission or carrier-transporting layer of electroluminescence devices.…”

“…In our previous paper, 30 1-octyl-7-(4-vinylbenzyl)indolo[3,2-b]carbazole (5) was prepared as a monomer compound by a reaction of 1-iodooctane with the INC anion derived from the reaction of INC with sodium hydride, followed by the addition of p-chloromethylstyrene. However, the yield of monomer 5 was very low because the mono-alkylation of the Nposition of INC proceeded with a large amount of byproduct, dialkylated INC, and so on.…”

“…30 It was found that the photonic properties, such as ultraviolet-visible absorption and the photoluminescence spectra of N-alkylated INC, were similar to those of INC, and the photoluminescence quantum yield of N-alkylated INC was 0.52-0.54. To investigate the fundamental characteristics of the INC moiety in the polymer, we designed a novel N-substituted monomer based on the INC moiety.…”

Syntheses and Photonic Properties of Copolymers Containing Indolocarbazole Moiety in the Side Chain

“…The maximum absorption and photoluminescence intensity were observed at 340 nm and 421 nm, respectively. It was found that the absorption and photoluminescence spectra of CP-1, CP-2 were similar to that of N, N'-dioctyl INC [8]. Therefore, the absorption and photoluminescence behavior of these copolymer solutions seemed to be derived from the INC moiety.…”

“…However, only few studies have been reported on the synthesis of INC-containing polymers. In our previous study [7][8][9], we have investigated the synthesis of a novel monomer containing indolocarbazole moiety, 1-(4-vinylbenzyl)-7-octylindolo[3,2-b]carbazole (VINC-C 8 ), and the copolymers of VINC-C 8 with styrene were prepared by a radical polymerization. Then, it was found that the obtained copolymers showed the amorphous state and the thermal stability of the copolymers increased as the INC content increased.…”