Synthesis, characterization and ion-binding properties of BODIPY scaffolds bearing sulfur function

Two new borondipyrromethene-based probes BODIPY1 and BODIPY2 were synthesized and evaluated. The chelators in the two probes, 8-aminoquinoline (AQ) and sulfur function, coordinate to Zn2+ in a synergic manner, thus the change in oxidation state of sulfur function (thioether to sulfoxide) would have sufficient effect on the photophysical response properties. As expected, both BODIPY1 and BODIPY2 display distinct fluorescence enhancement toward Zn2+. However, BODIPY1 and BODIPY2 show different binding properties. Pb2+ interferes with Zn2+ detection in BODIPY1 while has little influence on the fluorescence of BODIPY2, interfering that change of the oxidation state of the sulfur atom from thioether to sulfoxide benefits the Zn2+-specific fluorescence response.