Construction and investigation of dual-functional metal–organic frameworks (MOFs) with luminescent sensing and proton conduction provide widespread applications in clean energy and environmental monitoring fields. By selecting a phosphonic acid ligand 4-pyridyl-CH₂N(CH₂PO₃H₂)₂ (H₄L) and coligand 2,2′-biimidazole (H₂biim), two cadmium-based MOFs [Cd_1.5(HL)(H₂biim)_0.5] (1) and (H₄biim)_0.5·[Cd₂(L)(H₂biim)Cl] (2) with different structures and properties have been hydrothermally synthesized by controlling reaction temperature. Based on the excellent thermal and chemical stabilities, and good luminescent stabilities in water solution, 1 and 2 can serve as luminescent sensors of chloramphenicol (CAP) with different quenching constant (K_SV) values and detection limits (LODs) in water, simulated environmental system, and real fish water system. Meanwhile, different sensing effects and possible sensing mechanisms are analyzed in detail. Moreover, 1 and 2 can also serve as good proton-conducting materials. The proton conductivities can reach up to 1.41 × 10^–4 S cm^–1 for 1 and 1.02 × 10^–3 S cm^–1 for 2 at 368 K and 95% relative humidity (RH). Among them, 2 shows better luminescent sensing and proton conduction performance than 1, which indicates that different crystal structures have a great impact on the properties of MOFs. Through the discussion of the relationship between structures and properties in detail, the possible reasons for the differences in properties are obtained, which can provide theoretical guidance for the rational design of this kind of dual-functional MOFs in the future.

中文翻译：

---

两种稳定的 Cd-MOF 作为具有抗生素发光传感和质子传导的双功能材料

具有发光传感和质子传导功能的双功能金属有机框架（MOF）的构建和研究在清洁能源和环境监测领域提供了广泛的应用。通过选择膦酸配体 4-pyridyl-CH ₂ N(CH ₂ PO ₃ H ₂ ) ₂ (H ₄ L) 和辅助配体 2,2'-联咪唑 (H ₂ biim)，两个镉基 MOFs [Cd _1.5 ( HL)(H ₂ biim) _0.5 ] ( 1 ) 和 (H ₄ biim) _0.5 ·[Cd ₂ (L)(H ₂ biim)Cl] ( 2)通过控制反应温度水热合成了不同结构和性质的化合物。基于优异的热稳定性和化学稳定性，以及在水溶液中良好的发光稳定性，1和2可作为氯霉素（CAP）在水中具有不同猝灭常数（K _SV）值和检测限（LODs）的发光传感器，模拟环境系统和真正的鱼水系统。同时，详细分析了不同的传感效果和可能的传感机制。此外，1和2也可以作为良好的质子传导材料。质子电导率可达 1.41 × 10 ^–4 S cm ^–1对于1和 1.02 × 10 ^–3 S cm ^–1对于2在 368 K 和 95% 相对湿度 (RH) 下。其中，2比1表现出更好的发光传感和质子传导性能，表明不同的晶体结构对MOFs的性能有很大的影响。通过对结构与性能关系的详细讨论，得出了性能差异的可能原因，可为今后此类双功能MOFs的合理设计提供理论指导。