The development of dual-emitting materials capable of detecting hydrogen sulfide (H₂S) under environmental and biological conditions has garnered significant attention due to the gas’s dual role as a toxic industrial pollutant and an endogenous signaling molecule. In this study, a new chemically stable metal supramolecular complex, [Zn₂(pda)₂(H₂O)₃]·(H₂O)₀.₅ (Znpda), where pda = 1,10-phenanthroline-2,9-dicarboxylic acid, was synthesized via a solvothermal method. This complex features accessible uncoordinated carboxylic oxygen sites and exhibits high structural integrity in aqueous environments. By incorporating Eu³⁺ and Cu²⁺ ions into its coordination network through post-synthetic modification, we constructed a dual-emitting hybrid material, Eu³⁺/Cu²⁺@Znpda. In HEPES buffer solution (pH = 7.4), the material displays intense ligand-based emission and weak Eu³⁺ luminescence, indicating that the energy transfer from the organic ligand to Eu³⁺ is suppressed by Cu²⁺ ions—acting as a quencher via the “antenna effect” blockade.
Upon exposure to H₂S, which readily chelates with Cu²⁺ to form insoluble CuS, the quenching effect is reversed. The removal of Cu²⁺ restores the antenna effect, leading to a strong turn-on fluorescence response from Eu³⁺ while simultaneously reducing the ligand emission. This dual response enables ratiometric detection based on the intensity ratio between the 614 nm Eu³⁺ emission and the 386 nm ligand emission.TCEB2 Antibody Biological Activity We further designed an IMPLICATION logic gate using this ratio as the output signal, where the presence of both Cu²⁺ and NaHS (a H₂S donor) produces a binary “1” output, demonstrating intelligent molecular recognition capability.ATG3 Antibody MedChemExpress The system exhibits rapid response (<1 min), high sensitivity (limit of detection: 1.PMID:35168586 45 μM), and excellent selectivity over common interferents such as thiols, metal ions, and anions. These properties highlight the potential of Eu³⁺/Cu²⁺@Znpda as a robust, real-time fluorescent probe for monitoring H₂S in biological systems and environmental applications.
The synthesis of Znpda was confirmed by single-crystal X-ray diffraction, PXRD, FT-IR, and elemental analysis. The crystal structure reveals a 3D supramolecular network composed of dinuclear Zn(II) units linked by carboxylate and nitrogen atoms of pda ligands, stabilized by extensive hydrogen bonding and π–π stacking interactions. The framework contains open cavities with uncoordinated carboxylic oxygen atoms, ideal for hosting metal cations. Post-synthetic incorporation of Eu³⁺ and Cu²⁺ was verified by ICP-OES, XPS, and elemental mapping, confirming uniform distribution and coordination to the O-sites. Photoluminescence studies demonstrated that Eu³⁺@Znpda shows characteristic sharp emissions of Eu³⁺ upon excitation at 361 nm, while Eu³⁺/Cu²⁺@Znpda exhibits quenched Eu³⁺ emission and enhanced ligand fluorescence due to Cu²⁺-induced quenching.
Upon addition of NaHS, the fluorescence intensity ratio I₆₁₄/I₃₈₆ increased linearly from 0.42 to 11.88 across 0–1500 μM NaHS concentrations, with a good fit to the equation I = 0.017C + 0.449 (R² = 0.98374) in the 0–720 μM range. This allows accurate quantification of H₂S levels. The fast response time and minimal interference from other species underscore the practical utility of this probe. Notably, even in the presence of cysteine and glutathione—common thiol-containing biomolecules—the response remains selective for H₂S, thanks to the unique pore size and binding affinity of the Znpda framework.
In conclusion, this work presents a highly effective, dual-functional fluorescent platform based on a stable supramolecular zinc complex that combines turn-on sensing, ratiometric readout, and logic gate functionality for H₂S detection. Its compatibility with physiological conditions, low detection limit, and resistance to interference make it a promising candidate for future biomedical and environmental monitoring tools.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com