Regulating the Topologies and Photoresponsive Properties of Lanthanum‐Organic Frameworks

The development of low‐cost, high‐efficiency, stable, and structurally adjustable electrocatalysts for hydrogen evolution reaction (HER) is of great significance for energy conversion. In this study, two new Cu(I) coordination polymers (CPs), formulated as {[Cu(L1)](PF6)·CH2Cl2}n (1) and {[Cu2(L2)1.5(PPh3)](PF6)2}n (2) (L1 = 1,3‐bis[1‐(pyridin‐3‐ylmethyl) ‐1H‐benzimidazol‐2‐yl]propane, L2 = 1,4‐bis[1‐(3‐pyridylmethyl)‐1H‐benzimidazol‐2‐yl]butane), were synthesized by interfacial diffusion method and characterized by single‐crystal x‐ray diffraction and IR and UV–Vis spectra. Structural analysis shows that the CP‐1 is a one‐dimensional chain structure, whereas the CP‐2 is a two‐dimensional layered structure, which is due to the different coordination modes of ligands L1 (bridging chelation) and L2 (bridging). The electrocatalytic activity for HER of Cu(I) CPs was studied by preparing modified glassy carbon electrodes (CP‐1/GCE and CP‐2/GCE). Electrochemical HER studies manifest that in 0.5 M H2SO4, the overpotential (η10298K) and Tafel slope (b 298K) are −769 mV and 173 mV dec−1 for CP‐1/GCE, −933 mV and 301 mV dec−1 for CP‐2/GCE, and −930 mV and 298 mV dec−1 for bare/GCE, respectively. The η10298K and b298K of CP‐1/GCE were significantly positive shifted and decreased compared with the bare/GCE, indicating that CP‐1/GCE has significant electrocatalytic activity and electrocatalytic HER activity order is CP‐1/GCE > CP‐2/GCE ≈ bare/GCE. This work provides an important reference for the application of non‐noble metal CPs in the field of electrocatalysis.

Electrocatalytic Applications in Hydrogen Evolution of Two Nitrogen Heterocyclic Cu(I) Coordination Polymer Modified Electrodes

Wu,

Ma,

Teng

et al. 2024

Two New Luminescent Metal–Organic Frameworks as Fluorescent Sensors of Nitrobenzene, Fe³⁺, and Cr₂O₇²⁻

Xiong,

Yue,

Yao

et al. 2024

Two new luminescent metal–organic frameworks (MOFs), namely, [Zn2(HL)2]n (1) and {[Cd2(HL)2(H2O)2]⋅(H2O)0.5}n (2) [H3L = 5‐((4‐(1H‐1,2,4‐triazol‐1‐yl)benzyl)amino)isophthalic acid ligand], have been solvothermally synthesized and characterized. Single‐crystal x‐ray diffraction shows that 1 exhibits a 3D framework, whereas 2 features 2D network. Furthermore, the fluorescence studies demonstrated that 1 and 2 exhibited luminescent sensing activity for nitrobenzene (NB), Fe3+ ions, and Cr2O72− anions with high selectivity, high sensitivity, and low detection limit, the corresponding detection limits of 1 were 6.40 × 10−7, 1.26 × 10−7, and 1.44 × 10−7 M, respectively, and that of 2 were 2.42 × 10−6, 3.41 × 10−7, and 2.90 × 10−7 M, respectively. 1 and 2 exhibited excellent solvent, pH, and thermal stabilities. The results suggested that both 1 and 2 can be considered as potential fluorescent sensors of NB, Fe3+ ions, and Cr2O72− anions.

A Novel Multifunctional Eu (III)‐MOF Luminescence Sensor for Detecting NB, Fe³⁺, and Cr₂O₇²⁻ With Outstanding Sensitivities and Selectivities

Li,

Zhang,

Fan

et al. 2024

The bowl‐shaped flexible carboxylic acid zwitterion 1,1′,1″‐(2,4,6‐trimethylbenzene‐1,3,5‐triyl)tris (methylene)‐tris(4‐carboxy‐pyridinium)tribromide (H3LBr3) ligand‐based lanthanide metal–organic framework (Ln‐MOF) was synthesized for the first time under solvothermal conditions. Single crystal X‐ray diffraction analysis indicates that the molecular formula of Ln‐MOF is [EuL2(H2O)4Br3]·2H2O (1). Luminescence sensing experiments demonstrate that 1 shows obvious fluorescence quenching for nitrobenzene (NB), Fe3+, and Cr2O72− with low detection limits of 0.118 μM, 9.098 nM, and 17.409 nM, respectively. 1 can be regarded as a luminescence sensor with multiple functions, displaying high selectivity, wonderful antiinterference ability, outstanding sensitivity, and recyclability to detect NB, Fe3+, and Cr2O72−.