TMSOTf-Mediated Formal [4 + 2] Cycloaddition-Retro-aza-Michael Cascade of Vinylogous Carbamates for the Synthesis of Highly Fluorescent Pyridocarbazoles

Trimethylsilyl trifluoromethanesulfonate mediated dimerization reaction of vinylogous carbamates of carbazoles gave highly fluorescent pyridocarbazoles through a Povarov-type formal [4 + 2] cycloaddition-retro-aza-Michael cascade. The developed strategy was used to access indolo pyridocarbazole and quinolizinocarbazolone in an expeditious manner. Various coupling reactions were successfully performed on synthesized pyridocarbazoles to study the effect of electronics of substitution on photophysical properties. Synthesized carbazoles possess excellent photophysical properties with high quantum yields (Φ_F). Fluorescent carbazole dicarboxylic acid showed potential as a pH probe to give a linear response to pH over a very wide range (7.0-3.0) reflecting high efficiency.

Synthesis, structural characterization and computational study of NLO-responsive chromophores and second-order coefficients of thermally crosslinked polymers

The HOMO and LUMO structures of compounds 2, 4 and 6 with their band gap values.