5,12-Dihydroindolo[3,2-a]carbazole: A promising scaffold for the design of visible light photoinitiators of polymerization

5,12-Dihydroindolo[3,2-a]carbazole is a polycyclic structure combining in its scaffold two carbazole moieties sharing fused aromatic ring. Since the pioneering works reported 2019 on this concerning substitution of carbazoles by similar functional groups, no recent investigation has been devoted to asymmetrize carbazoles. In work, series 13 compounds based 5,12-dihydroindolo[3,2-a]carbazole presented. By carefully controlling reaction conditions, groups such as formyl, nitro or an acetyl group could be selectively introduced one X-ray diffraction and 2D NMR experiments, higher reactivity clearly evidenced, enabling generate asymmetrically substituted structures. Thanks unprecedented approach scaffold, absorption resulting dyes shifted towards visible range whereas parent (5,12-dihexyl-6,7-diphenyl-5,12-dihydroindolo[3,2-a]carbazole) exhibits strongly UV-centered absorption. light their properties, several have examined photoinitiators polymerization activable at 405 nm under low intensity two-component photoinitiating systems for free radical acrylates cationic epoxides. Chemical mechanisms supporting different processes fully elucidated techniques including cyclic voltammetry, UV–visible photoluminescence spectroscopy well photolysis experiments.