A highly selective “ON-OFF” probe for colorimetric and fluorometric sensing of Cu²⁺ in water

We present herein a diformyl phenol based probe, 3-({3-[2,3-dihydroxy-propylimino-methyl]-2-hydroxy-5-methyl-benzylidene}-amino)-propane-1,2-diol (H₅dpm), as a colorimetric and fluorometric chemosensor for selective detection of Cu²⁺ in aqueous solution under physiological conditions. This simple system produces a colorimetric change enabling naked eye detection as well as on-off fluorescence response towards Cu²⁺ in an aqueous medium with a detection limit of 11.2 nM. To further demonstrate the utility of H₅dpm, we next explored the application of H₅dpm for imaging Cu²⁺ in Vero cells. The attractive imaging properties of the H₅dpm probe will open up avenues for molecular imaging and biomedical applications.