Enhanced Benzene Adsorption\nin Chloro-Functionalized\nMetal–Organic Frameworks

The functionalization of metal–organic frameworks\n(MOFs)\nto enhance the adsorption of benzene at trace levels remains a significant\nchallenge. Here, we report the exceptional adsorption of trace benzene\nin a series of zirconium-based MOFs functionalized with chloro groups.\nNotably, MFM-68-Cl<sub>2</sub>, constructed from an anthracene linker\nincorporating chloro groups, exhibits a remarkable benzene uptake\nof 4.62 mmol g<sup>–1</sup> at 298 K and 0.12 mbar, superior\nto benchmark materials. In situ synchrotron X-ray diffraction, Fourier\ntransform infrared microspectroscopy, and inelastic neutron scattering,\ncoupled with density functional theory modeling, reveal the mechanism\nof binding of benzene in these materials. Overall, the excellent adsorption\nperformance is promoted by an unprecedented cooperation between chloro-groups,\nthe optimized pore size, aromatic functionality, and the flexibility\nof the linkers in response to benzene uptake in MFM-68-Cl<sub>2</sub>. This study represents the first example of enhanced adsorption\nof trace benzene promoted by −C<u>H</u>···Cl\nand Cl···π interactions in porous materials.