Synthesis and photophysical properties of a new ESIPT fluorophores based on 4,6-diaryl-2-(1-hydroxy-4-nitronaphthalen-2-yl)pyridine

A series 4,6-diaryl-2-(1-hydroxy-4-nitronaphthalen-2-yl)pyridines were prepared by Kröhnke pyridine synthesis method. The tautomerism and fluorescent properties of the synthesized compounds are considered depending on the structure, the polarity of medium under neutral conditions and in the presence trifluoroacetic acid in DMSO. The resulting ESIPT fluorophores are characterized by dual emission and exist in two tautomeric forms under neutral conditions in DMSO.