Colorimetric and fluorimetric detection of fluoride and cyanide ions using tri and tetra coordinated boron containing chromophores

Abstract

Two organoboron based fluorophores pyrazabole 3 and BODIPY 4 have been designed and synthesized by the Pd-catalyzed Sonogashira cross-coupling reaction and successfully employed for fluoride and cyanide ion sensing. Pyrazabole 3 acts as a fluorimetric sensor, whereas BODIPY 4 acts as a fluorimetric as well as colorimetric sensor for fluoride and cyanide ions with ratiometric response. The photophysical properties of pyrazabole 3 and BODIPY 4 exhibit good electronic communication between triarylborane and pyrazabole/BODIPY. The single crystal X-ray structure of the pyrazabole 3 shows a chair conformation for the pyrazabole core. The packing in pyrazabole 3 and BODIPY 4 shows interesting supramolecular structures. The computational studies show good agreement with the experimental results.