Simple terpyridine based Cu(II)/Zn(II) complexes for the selective fluorescent detection of H₂S in aqueous medium

Simple 4′-phenyl-2,2′:6′,2″-terpyridine derived metal complexes (1.Cu and 1.Zn) are studied for selective detection of H₂S, based on metal displacement approach. Probe 1.Cu exhibits turn-on and 1.Zn exhibits turn-off fluorescence detection of H₂S both in aqueous buffer and biological medium. In the presence of H₂S, fluorescent output signal turned ON or OFF by simply changing the metal from copper to zinc in terpyridine coordination center. The advantages of the probes include a low detection limit (2.2 μM for 1.Cu and 31 μM for 1.Zn), fluorescent response, good selectivity, high sensitivity and fast response (45–60 s) and easy to synthesize the probe. Furthermore, the detection of H₂S could be used for the construction of INHIBIT and NAND molecular logic gates based on the optical signal. - Highlights: • A simple and efficient Terpyridine based fluorescent H₂S sensor is described. • Probe 1.Cu exhibits turn-on fluorescence detection in water. • The response time of 1.Cu was found to be faster as compared to 1.Zn. • The probes had high sensitivity and selectivity with H₂S. • H₂S detection also used for the construction of molecular logic gates INHIBIT and NAND.