A New off-on Fluorescence Zinc Ion Sensors Based on Iodo- and Bromosubstituted Dipyrromethenes

Monoiodo- and dibromsubstituted dipyrromethenes HL1 - HL3 were described as a highly sensitive and selective Off-On fluorescent chemosensor for Zn2+ based on the chelation-enhanced fluorescence (CHEF) effect. Coordination reactions of HL1 - HL3 with Zn2+ cations are accompanied by a significant (124 to 215-fold) increase in fluorescence intensity against the background of other metal ions in the binary propanol-1/cyclohexane mixture (1:30). The fluorometric detection limit of Zn2+ ions using HL1 - HL3 sensors is from 3.0.10(-8) to 3.3.10(-9) mol/L. The presence of Na+, K+, Ca2+, Mg2+, Mn2+, Ni2+, Co2+, Pb2+ cations does not interfere with the detection of Zn2+. Complexation reactions are accompanied by a visual change in the color of the solution from yellow-orange to pink-raspberry so that the HL1 - HL3 ligands can also be used as a naked-eye indicators of the presence of Zn2+ ions.

Automated summary

Monoiodo- and dibromsubstituted dipyrromethenes HL1 - HL3 are described as highly sensitive and selective Off-On fluorescent chemosensors for Zn2+ based on the chelation-enhanced fluorescence (CHEF) effect. Coordination reactions with Zn2+ cations result in a significant increase in fluorescence intensity, and the detection limit for Zn2+ ions using HL1 - HL3 sensors is from 3.0.10(-8) to 3.3.10(-9) mol/L.