Multi-Stimuli-Responsive Fluorescence Switching of a Donor−Acceptor π-Conjugated Compound

Abstract

An electron donor−acceptor structured π-conjugated organic compound <b>1</b> composed of trifluoromethyl-biphenyl and cyano-stilbene-amine was designed and exhibited multi-stimuli-responsive fluorescence switching behaviors. The synthesized solid exhibited piezochromism in that grinding and heating could change the emission colors between orange-red and yellow. The amorphous <b>1</b> also showed interesting vapochromic behavior in that organic vapor could convert the yellow color into orange. The solution of <b>1</b> exhibited nearly no fluorescence at room temperature and intensive yellowish green emission at 77 K, while adding CF₃COOH (TFA) resulted in green emissive state at room temperature and blue fluorescent state at 77 K