Halogen-engineered metal-organic frameworks enable high-performance electrochemical glucose sensing

The introduction of halogen atoms into the skeleton to regulate the intrinsic properties or improve task-specific performance of metal-organic frameworks (MOFs) has developed rapidly in recent years. Herein, a series of halogen-engineered MOFs were designed and prepared for electrochemical glucose sensing. Three isomorphic Ni-MOFs were constructed by using tetra-halogenated-phthalic acids as the organic ligand and incorporating 4,4 '-bipyridine as an auxiliary ligand. Halogen atoms can enhance the stability of Ni-MOFs through their hydrophobicity and interlayer halogen bonds (X-X or X-pi, X = F, Cl, Br). Combined experimental and theoretical results show that the hydrogen bond between halogen atoms and glucose improves the reaction thermodynamics, enabling the wide linear range of 0.01-5.0 mM, high sensitivity of 4709.9 mu A mM-1 cm-2 and low detection limit of 0.043 mu M. This work provides practical guidance for the rational design of halogenated MOFs and promotes their applications in electrochemical sensing. A series of isomorphically halogen-engineered MOFs are synthesized for electrochemical glucose sensing. By tuning the electronegativity of the halogen atom on the MOF skeleton, the sensing performance are significantly improved.