Heterometallic Metal-Organic Framework Based on [Cu4I4] and [Hf6O8] Clusters for Adsorption of Iodine

Heterometallic metal-organic framework (MOF) as a kind of porous material is very important because of its excellent properties in catalysis, magnetic, sensor, and adsorption fields, but the reasonable design and syntheses of these are still challenging. Herein, we prepared one heterometallic MOF with the formula [Hf6(μ3-OH)8(OH)8][(Cu4I4) (ina)4]2·22DMF (NS-1, ina = isonicotinate). Single-crystal X-ray diffraction analysis revealed that NS-1 is a three-dimensional network with flu topology, constructed from 8-connected [Hf6(μ3-OH)8(OH)8]8+ and 4-connected [Cu4I4] clusters as second building units (SBUs). To our best knowledge, NS-1 is a rare example with two different metal clusters as SBUs in heterometallic Hf-based MOFs. Interestingly, NS-1 exhibits a reversible adsorption performance for iodine in the cyclohexane solution, the adsorption kinetics fits well with the pseudo-second-order equation, and the Freundlich model relating to multilayer adsorption better describes the process of iodine absorption.