Chloroform-Driven Excited-State Protonation of Pyrene-Dialkylaniline Derivatives Under Visible Light.

The photophysical and photochemical properties of the organic chromophores are predominantly governed by the aromatic core, electron-donating/withdrawing groups, and inter- and intramolecular electrostatic interactions, while alkyl chains contribute marginally due to their weaker inductive effect. To investigate alkyl chain effects, we synthesized 1-pyrene substituted with N,N-dialkylanilines (C2, C6, C10) via Suzuki coupling. Solvatofluorochromic studies revealed a red-shifted fluorescence with increasing solvent polarity, except in chloroform and methanol, attributed to solute-solvent interaction between solvent proton and the nitrogen atom of N,N-dialkylamine.