Design and synthesis of fluorescent reagents for selective detection of dopamine

•A novel fluorescent probe has been developed for the detection of dopamine.•This reagent indicated significant fluorescence enhancement by the reaction with dopamine.•The proposed molecule showed the highly sensitive and selective detection of dopamine. I report the development of (E)-2,2′-(5-(2-(4-(dicyanomethylene)-6-methyl-4H-pyran-2-yl)vinyl)-2-hydroxy benzylazanediyl)diacetic acid Fe(II) complex (1-Fe2+), a fluorescent reagent that can be used to detect dopamine. 1-Fe2+ was constructed using the cyanopyranyl group as the fluorophore and an Fe2+ complex both as the ligand exchange site and fluorescence quenching moiety. In contrast to the weak fluorescence emission of 1-Fe2+ in the absence of dopamine, a much stronger fluorescence emission was observed following the addition of dopamine owing to the release of Fe2+ from compound 1, which indicates significant fluorescence enhancement and the binding of Fe2+ to dopamine. The fluorescence intensities of the reagent were plotted as a function of the dopamine concentration and a good linear relationship was observed. The reaction of 1-Fe2+ with dopamine was not affected by the presence of foreign substances, thereby allowing for the highly selective detection of dopamine. The experimental results clearly showed that 1-Fe2+ is a good dopamine indicator, and it can be widely employed in dopamine detection protocols.