基于联吡啶的 Cu(II) MOF：拓扑、磁性和探索多种硝基芳香族炸药的传感能力

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Cu(II) MOFs Based on Bipyridyls: Topology, Magnetism, and Exploring Sensing Ability toward Multiple Nitroaromatic Explosives

In this work, a series of three copper(II) metal-organic frameworks (MOFs), [Cu(4,4′-DP)Cl]_n (1), [Cu(4,4′-DP)_0.5Cl]_n (2), and [Cu(4,4′-TMDP)Cl]_n (3) (4,4′-DP = 4,4′-dipyridyl, 4,4′-TMDP = 4,4′-trimethylenedipyridyl), is designed and synthesized under solvothermal conditions. Crystallographic investigations reveal that 1 and 2 have tetrahedral and 3 has octahedral environment around the Cu(II) ion. By varying the solvent conditions and ligand derivatives, the topology can be interestingly tuned. TOPOS Pro provides topological conclusions that 1 is stabilized by unusual 2D + 2D → 3D polycatenation of layers lying in (110) and (11̅0) planes with dihedral angle of 90° showing altogether fes, hcb, and sql topologies. On the other hand, 2 exhibits a bey (3,4-c net) topology and 3 shows 4-fold interpenetration with the dia topology. The dc measurements for 1–3 performed on polycrystalline samples in a 0.1 T field confirm strong ferromagnetic behaviors for 1 and 2 and moderate antiferromagnetic behavior for 3. To examine the sensing properties of the three MOFs, various hazardous nitroaromatic compounds (NACs) were used as analytes. While 1 is a potent fluorescence sensor for highly sensitive detection of multiple NACs, 2 selectively detects meta-dinitrobenzene (m-DNB) with K_SV = 5.73 × 10⁵ M^–1 and a remarkably lower limit of detection (LOD) value of 1.23 × 10^–7 M. 3 does not show sensing ability toward any NAC probably due to the coordination environment being different from those in 1 and 2. The work demonstrates fine-tuning of the topology and in turn magnetic and sensing properties by changing the reaction conditions.