A novel ratiometric fluorescent probe for selective and sensitive detection of Cu2+ in complete aqueous solution

A novel hemicyanine-based ratiometric fluorescent probe 3 for Cu2+ was described. The probe exhibited fluorescence emission at 448nm. Upon addition of Cu2+, the emission at 448nm quenched and simultaneously generated a significant bathochromic shift of the emission maximum to 503 nm due to the Cu2+-triggered hydrolysis reaction of the picolinate moiety. Thus, a singl-excitation, dual-emission ratiometric measurement with a large red shift in emission (triangle 55 nm) and remarkable changes in the ratio (F-503nm/F-448nm) of the emission intensity (R/R-o up to 22-fold) could be established. Moreover, the probe exhibited a large Stokes shift, high sensitivity (detection limit of 1.1 nM), and high selectivity for Cu2+ over other metal ions in complete aqueous solution. (C)2017 Elsevier B.V. All rights reserved.