Th₆-Based Multicomponent Heterometallic Metal–Organic Frameworks Featuring 6,12-Connected Topology for Iodine Adsorption

Abstract

Its high coordination number and tendency to cluster make Th 4+ suitable for constructing metal–organic frameworks (MOFs) with novel topologies. In this work, two novel thorium-based heterometallic MOF isomers (IHEP-17 and IHEP-18) were assembled from a Th 6 cluster, a multifunctional organic ligand [4-(1 H -pyrazol-4-yl)benzoic acid (HPyba)], and Cu 2+ /Ni 2+ cations via the one-pot solvothermal synthesis strategy. The framework features a 6,12-connected new topology net and contains two kinds of supramolecular cage structures, Th 36 M 4 and Th 24 M 2, suitable for guest exchange. Both MOF materials can efficiently adsorb I 2 . X-ray photoelectron spectroscopy, Raman spectroscopy, and single-crystal X-ray diffraction indicate that the adsorbed iodine is uniformly distributed within the Th 36 M 4 cage but not the Th 24 M 2 cage in the form of I 3 – .