A microporous shp-topology metal-organic framework with an unprecedented high-nuclearity Co_(10)-cluster for iodine capture and histidine detection

摘要

Herein we report the synthesis of a microporous shp-topology metal-organic framework (JNU-200) with 12-connected high-nuclearity Co_(10)-cluster and 4-connected carboxylate ligand, 4,4',4",4"'-(pyrazine-2,3,5,6-tetrayl)tetrabenzoate (BTTB). The redox potential of Co~(2+)/Co~(3+) 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 MOF materials reported so far. Kinetic studies show that JNU-200 can capture most of the 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 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.