A Rhodamine B-Salicylic Acid Compound with Colorimetric /Fluorescent Dual Channel Response for the Identification of Fe3+

Abstract

In this paper, a rhodamine B-salicylic acid based binary compound probe RB-SA was designed and synthesized, and its structure was characterized by 1HNMR and 13CNMR. The probe provides a colorimetric/fluorescent dual-channel response to Fe3+ in the aqueous phase. Under the induction of Fe3+, the spirolactam ring of the probe RB-SA changed from closed loop to open loop, and a new absorption peak appeared at 560 nm and the solution color changed from colorless to red, while the fluorescence signal turned on, and the fluorescence intensity at 587 nm increased linearly with the addition of Fe3+. It was shown that the probe RB-SA exhibited high sensitivity to Fe3+, with a minimum detection limit (LOD) of 5.19 nM and a complexation constant of 1.03 × 104 M-1 based on fluorescence spectroscopy titration data.