Synthesis, sensor activity, and logic behavior of a highly water-soluble 9,10-dihydro-7H-imidazo[1,2-b]benz[d,e]isoqionolin-7-one dicarboxylic acid

•A novel highly water-soluble fluorescent dihydroimidazonaphthalimide derivative is synthesized.•Compound is designed as fluorescent “off–on–off” molecular pH probes based on PET and ICT.•Probe manifests selective response to protons over representative transition metal ions in 100% aqueous medium.•Logic functions AND, XOR, INH, and XNOR are achieved.•A magnitude digital comparator and half-adder are demonstrated.

The design, synthesis, and sensor activity of a novel highly water-soluble 9,10-dihydro-7H-imidazo[1,2-b]benz[d,e]isoqionolin-7-one derivative are reported. The changes in the photophysical properties of the compound as a function of pH were investigated in 100% aqueous medium. Novel compound manifests ratiometric “off–on–off” pH sensor activity. Due to the two different “off”-states, it is able to execute the logical functions AND and XOR as well as INH and XNOR and as such, to act as a half-adder and a magnitude digital comparator, respectively. The synthesized compound shows excellent selectivity toward protons over the representative metal ions in ammonia/ammonium chloride buffer (pH 10) and HEPES (pH 7.3) solutions. The high water solubility and excellent pH selectivity and sensitivity of the probe may be beneficially for monitoring pH variations in complex samples.

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