Coumarin-based fluorescent sensors for zinc(II) and hypochlorite

Two new fluorescent chemosensors have been designed and synthesised through functionalisation of a common 7-aminocoumarin precursor. One sensor features a di(2-picoyl)amine metal ion-binding moiety that allows for selective detection of Zn2+ ions over other common cations in aqueous solution, with the sensor exhibiting a 5.4-fold increase in fluorescence upon Zn2+ binding (limit of detection = 26 nM). The second sensor incorporates an aminophenyl group designed to react with highly reactive oxygen species (hROS). This sensor reacts with ClO−  in preference to other ROS, exhibiting a 27-fold increase in fluorescence upon the addition of 150 equivalents of ClO−  (limit of detection = 2 μM).