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

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