A benzothiazole containing CHEF based fluorescence turn-ON sensor for Zn2+ and Cd2+ and subsequent sensing of H2PO4− and P4O74− in physiological pH

• Turn-ON fluorescence and colorimetric zinc sensor in a mixed buffered solution.
• The sensor also responds to hazardous cadmium ion as fluorescent turn-ON sensor.
• Pyrophosphate and dihydrogen phosphate sensing through metal complex ensembles.
• The reversible and recyclable binding responds to a INHIBIT logic gate.

A benzothiazole functionalized chemosensor L1, exhibited colorimetric as well as fluorometric response to Zn2+ ion at physiological pH based on CHEF process. Selective naked eye detection of Zn2+ ion over most of the biologically important cations was also demonstrated. Sensing of biologically hazardous cadmium ion was also possible with L1. Further, both the zinc and cadmium ensembles of L1 were found to respond P4O74− and H2PO4− anion among other important biological anions and nucleotides via fluorescence quenching. Chemosensor L1, was also found to be reversible and recyclable toward Zn2+ and pyrophosphate ions over more than six cycles and responds to a INHIBIT logic gate. NMR titration and theoretical calculations were also conducted to understand the sensing behavior of L1.