1,4-diaryl-1-oxy-1,3-butadiene conjugated system incorporated in a dibenzobarrelene skeleton: Synthesis, photophysical properties, and comparison with the heavier group 16 congeners

Abstract

We have synthesized the 1,4-diaryl-1-thio-, seleno- and telluro-1,3-butadiene derivatives incorporated in a dibenzobarrelene skeleton and found that the thio and seleno derivatives are highly fluorescent in solution at room temperature. We report here the synthesis of the oxygen congener. The compounds were synthesized by the reaction of anthranolate with 1,4-diaryl-1,3-butadiyne followed by an intramolecular cycloaddition. Their structures were analyzed by X-ray crystallography to reveal high planarity of the 1,4-diaryl-1-oxy-1,3-butadiene moieties compared with the heavier chalcogen congeners. The oxy compounds are fluorescent similarly to the thio and seleno congeners; the diphenyl and bis(4-trifluorophenyl) derivatives exhibited somewhat red-shifted fluorescence spectra with vibrational structure. Fluorescence of the D-φ-A type derivatives reached to the red and near infrared regions. The bonding characters in the 1-chalcogeno-1,3-butadiene moieties are discussed on the basis of DFT calculations.