Stable Microporous Metal–Organic Framework\nBased on Tritopic Pyrazolate Ligand for Xe/Kr Separation

Pyrazolate\nligands, renowned for their potent electron-donating\ncapabilities, have emerged as promising building blocks for the construction\nof stable metal–organic frameworks (MOFs) particularly when\npaired with late transition metals. While a plethora of diverse MOFs\nhave been meticulously crafted using ditopic pyrazolate ligands, the\nrealm of multidentate pyrazolate-based MOF structures remains relatively\nunexplored. This research unveils a notable achievement in the synthesis\nof a novel three-dimensional microporous MOF, characterized by its\nsingle-crystal form, meticulously assembled from a tritopic pyrazole\nligand and cobalt ions. This structure exhibits high structural robustness,\nwithstanding pH conditions ranging from 4 to 12. The robust framework,\nadorned with micropores, bestows upon it an exceptional ability to\nperform durable and efficient xenon (Xe)-krypton (Kr) separation.\nIt demonstrates a high Xe uptake of 23.80 cm<sup>3</sup> g<sup>–1</sup> (1.06 mmol g<sup>–1</sup>) at 0.1 bar and 55 cm<sup>3</sup> g<sup>–1</sup> (2.46 mmol g<sup>–1</sup>) at 1 bar,\nalong with a notable selectivity of 13 for Xe over Kr.