A Microporous shp-Topology Metal–Organic Framework with an Unprecedented High-Nuclearity Co10-Cluster for Iodine capture and Histidine Detection

Herein we report the synthesis of a microporous metal–organic framework (JNU-200) underlying a rare shp topology with 12-connected high-nuclearity Co10-cluster and 4-connected carboxylate ligand, 4,4',4'',4'''-(pyrazine-2,3,5,6-tetrayl)tetrabenzoate (BTTB). The redox potential of Co2+/Co3+ and the nitrogen-containing π-electron-rich BTTB render JNU-200 an ideal platform for iodine capture. Indeed, the adsorption capacity in iodine vapor can reach up to 1.08 g g–1, comparable to the best-performing MOFs materials reported so far. Kinetic studies show that JNU-200 can capture most of I2 from an iodine solution of 200 ppm within 48 h, corresponding to 99% removal efficiency, far exceeding many reported MOF materials. Single crystal X-ray diffraction was studied to reveal the structural changes of JNU-200 upon iodine adsorption and the precise location of the trapped iodine. Raman spectra analysis was performed to shed light on the host-guest interactions and the iodine adsorption mechanism. Furthermore, JNU-200 exhibits a rapid and facile detection of histidine (His) with a luminescence turn-on response and a yellowish precipitate which was confirmed to be a mixture of cobalt complexes with His.