A coumarin-quinolinium-based fluorescent probe for ratiometric sensing of sulfite in living cellsElectronic supplementary information (ESI) available: Experimental procedures, characterization data, and additional spectra. See DOI: 10.1039/c4ob00132j

Based on a novel coumarin-quinolinium platform, probe 2 was rationally designed and synthesized as a novel ratiometric fluorescent sensor for sulfite anions. The probe exhibited a wide dynamic concentration range for sulfite anions in a PBS buffer (containing 1 mg mL −1 BSA). More importantly, the probe was suitable for ratiometric fluorescence imaging in living cells with high sensitivity, favorable selectivity, and minimal cytotoxicity. Based on a novel coumarin-quinolinium platform, compound 2 was rationally designed and synthesized as a novel ratiometric fluorescent sensor for sulfite anions.