A novel pyridylvinyl naphthalimide-rhodamine dye: Synthesis, naked-eye visible and ratiometric chemodosimeter for Hg2+/Fe3+

Abstract

In this work, a novel pyridylvinyl rhodamine-naphthalimide ratiometric fluorescent probe, In this work, a novel pyridylvinyl rhodamine-naphthalimide ratiometric fluorescent probe, RNVP, was synthesized and characterized by 1H NMR, 13C NMR and HRMS techniques. This probe shows high selectivity and sensitivity towards Fe3+ and Hg2+. At a low concentration of Fe3+/Hg2+, a new emission peak appeared at 581nm and enhanced significantly along with naked-eye sensitive color changes, which spirolactam-ring moiety of rhodamine was converted to the open-ring form in the presence of Fe3+/Hg2+. Further addition of Fe3+/Hg2+, the fluorescence intensity at 438nm was enhanced rapidly, which attributed to the suppression of the PET process. The proposed sensing system of probe RNVP represented dual-channel and segment detection behavior, with the fluorescence “turn-On or Off” response and a very low detection limit of 2.72×10−8M and 9.08×10−8M, and the dissociation constant (Kd) were calculated to be 4.95×10−7 M3/2 and 6.68×10−8 M3/2, respectively. RNVP also quick responded linearly to the acidic solution and monitor the pH change in the range of 2.92–4.5, as well as excellent reversibility.