Comparative Study of Nitro- and Azide-Functionalized Zn

Selective detection of H2 S in the cellular systems using fluorescent CPs/MOFs is of great scientific interest due to their outstanding aqueous stability, biocompatibility and real-time detection ability. Fabrication of such materials using complete biologically essential elements and applying them as an efficient biosensor is still quite challenging. In this context, two newly synthesized CPs containing biologically essential metal ion (Zn) and nitro/azido functional groups into the framework to sense extracellular and intracellular H2 S by reducing into respective amines are presented. The CP-1 containing the azide group acted as an efficient fluorescent turn-on probe with the lowest detection limit (7.2 μM) and shortest response time (30 s) among the Zn-based probes reported till date. Moreover, CP-1 exhibited green luminescence in live cells after imaging a very low concentration of H2 S, whereas the nitro analogue CP-2 could not detect the target analyte due to its framework disruption.