A chromene pyrazoline derivatives fluorescent probe for Zn2+ detection in aqueous solution and living cells

Abstract A new chromene pyrazoline derivatives fluorescent probe L was designed and synthesized. The probe L appears in a 55-fold fluorescence enhancement after 5 equiv. Zn 2+ was added, and it also exhibits high sensitivity and selectivity for response to Zn 2+ in ethanol-water (V:V = 1:1) solution through “OFF-ON” type process and a possible photoinduced electron transfer (PET). Notably, the probe L distinguishes between Zn 2+ and Cd 2+ . The association constant was considered as 2.38 × 10 3  M −1 via fluorescence titration experiments. The probe L-Zn 2+ complex forms a 1:1 binding stoichiometry which was discussed by Job’s plot. The probe is very highly sensitive with fluorometric detection limit of 1.603 × 10 −10  M. It also shows good reversibility upon addition of EDTA. Furthermore, the viability of L to Zn 2+ has practical application in live cell imaging.