Tricyanopyrroline-based colorimetric NIR probe for rapid 'naked-eye' fluoride ion detection

Herein, two tricyanopyrroline based NIR dyes (TCP-Tph and TCP-HyDe) have been developed. These NIR dyes are highly sensitive to solvent polarity and the nature of solvents, and display reverse solvatochromic properties in solution. Both dyes act as a probe for selective fluoride ion detection in "naked eye" over various anions. The site-specific mechanistic study for establishing interaction between probe and fluoride ion has been investigated in solution. Moreover, these probes are also used for highly effective real-time monitoring of fluoride ions in toothpaste (in solution) and sewage water. A cost-effective paper-based fluoride detection kit (solid state) also developed.