A medium-controlled fluorescent enhancement probe for Ag+ and Cu2+ derived from pyrene-containing schiff base

A fluorescent enhancenment probe (1) derived from pyrene-containing Schiff base was developed and synthesized for the detection of Ag+ and Cu2+ in aqueous solutions. In THF-HEPES buffer solution (20.0 mM HEPES, 1:9, v/v, pH 7.4), probe 1 shows a highly selective and sensitive fluorescent enhancement recognition of Ag+ with a binding ratio of 1:1 (probe 1: Ag+) and a detection limit of 4.8 nM. In THF-HEPES buffer solution (20.0 mM HEPES, 3:7, v/v, pH 7.4), probe 1 shows a highly selective and sensitive fluorescent enhancement recognition to Cu2+ with a binding ratio of 1:2 (probe 1: Cu2+) and a detection limit of 4.2 nM. Further invesitgation with NMR and UV-vis experiments indicates that the different fluorescent recognition to Ag+ and Cu2+ are due to different binding modes of 1-Ag+ and 1-Cu2+ in different solutions.