5,12‐Dihydroindolo[3,2‐a]Carbazole Derivatives‐Based Water Soluble Photoinitiators for 3D Antibacterial Hydrogels Preparation

Abstract Indolo[3,2‐a]carbazole alkaloids have drawn a growing interest in recent years owing to their potential electrical and optical properties. With 5,12‐dihydroindolo[3,2‐a]carbazole serving as the scaffold, two novel carbazole derivatives are synthesized in this study. Both compounds are extremely soluble in water, with solubility surpassing 7% in weight. Intriguingly, the introduction of aromatic substituents contributed to drastically reduce the π‐stacking ability of carbazole derivatives, while the presence of the sulfonic acid groups enables the resulting carbazoles remarkably soluble in water, allowing them to be used as especially efficient water‐soluble PIs in conjunction with co‐initiators, i.e., triethanolamine and the iodonium salt, respectively, employed as electron donor and acceptor. Surprisingly, multi‐component photoinitiating systems based on these synthesized carbazole derivatives could be used for the in situ preparation of hydrogels containing silver nanoparticles via laser write procedure with a light emitting diode (LED)@405 nm as light source, and the produced hydrogels display antibacterial activity against Escherichia coli.