Stable Eu3+/Cu2+-Functionalized Supramolecular Zinc(II) Complexes as Fluorescent Probes for Turn-On and Ratiometric Detection of Hydrogen Sulfide

Fabrication of dual-emitting materials for H2S sensing under environmental and biological conditions is currently of great interest. In this work, a new chemically stable metal supramolecular complex [Zn-2(pda)(2)(H2O)(3)]center dot(H2O)(0.5) (Znpda, pda = 1,10-phenanthroline-2,9-dicarboxylic acid), with accessible uncoordinated carboxylic oxygen sites, is solvothermally synthesized. It can serve as a host in luminescent hybrid composites. By incorporating Eu3+ and Cu2+ in the supramolecular coordination network, we obtained the dual-emitting hybrid material Eu3+/ Cu2+@Znpda, which simultaneously shows intense ligand and weak Eu3+ emissions in HEPES buffer solution. Since H2S can easily chelate with Cu2+ and recover the blocked antenna effect between the ligand and Eu3+, Eu3+/Cu2+@Znpda possesses both the turn-on and ratiomectric fluorescence response to H2S. Accordingly, we designed an IMPLICATION logic gate for H2S recognition by employing the fluorescence intensity ratio between the ligand and Eu3+ as the output signal. In addition, Eu3+/Cu2+@ Znpda shows a fast response (<1 min) and high sensitivity (1.45 mu M) to H2S over other interfering species in the HEPES buffer solution, highlighting its potential use for H2S sensing under environmental and biological conditions.

Automated summary

The fabrication of dual-emitting materials for H2S sensing is currently a popular topic. A new chemically stable metal supramolecular complex was synthesized and used as a host in luminescent hybrid composites. By incorporating Eu3+ and Cu2+ in the coordination network, a dual-emitting hybrid material was obtained, showing a fast response and high sensitivity to H2S in HEPES buffer solution.