Fluorescent indolocarbazoles: Photophysical properties, DFT studies and selective detection of CF3COOH

The molecules containing the indolocarbazoles motif have attracted significant attention over the years, owing to the diverse implication of indolocarbazoles scaffolds in medicinal chemistry, photoelectronic materials and chromophores. In this work, the cobalt-catalyzed intramolecular oxidative cyclization of bi-indolnaphthoquinones under ligand-free conditions for the synthesis of indolocarbazoles has been developed. The synthesized products were evaluated on the photophysical properties and exhibited interesting fluorescence properties, which is promising for fluorescent probes. Each compound showed a colorimetric response upon addition of CF3COOH in contrast to other acids and the colorimetric sensors are even better, as the signaling event can be detected by the naked eye itself. Performed density functional theory (DFT) calculation helped to estimate quantum chemical reactivity parameters including electronic structure and reactivity of the synthesized compounds.