An azo dye-coupled tripodal chromogenic sensor for cyanide

A tripodal receptor bearing phenol as a hydrogen bond donor site and azo dye as the signaling subunit was synthesized. The receptor had a high binding affinity for CN− as signaled by the change in the color of a solution of sensor 4 upon addition of CN−. Using UV–Vis spectroscopy, the system can be used to quantify 0–19 × 10−5 mol L−1 of CN−, and the sensor was found to successfully function in the presence of other anions.