Aluminum Cluster Molecular Ring-Based Heterometallic Framework Materials for Iodine Capture

With the development of the nuclear industry, the risk of elements that are difficult to degrade in nuclear fission has been gradually increasing. Therefore, the efficient capture of iodine (I₂) has attracted considerable attention in recent years. The aluminum cluster-based metal framework materials show great advantage in iodine adsorption due to the designable pore sizes, excellent physicochemical stability, and cheap raw materials. Herein, two cases of aluminum cluster-based heterometal framework materials, [Al₁₀Cu^I₂I₂(CH₃O)₂₀(INA)₁₀]_n (1) and [Al₃Cu^I_0.5Cu^II_0.25(INA)₃(CH₃O)₆·Cl_0.75]_n (2), were assembled by isonicotinic acid (HINA), aluminum isopropoxide, and CuI. Their structures feature ringy Al₁₀ and Al₁₂ clusters as the secondary building units (SBUs) and Cu/CuI-pyridine as the linkers. Moreover, they can capture iodine from cyclohexane solution with high elimination rates and uptake amounts (93%, 0.772 g/g for 1; 98%, 0.810 g/g for 2). The better I₂ adsorption performance for 2 may be ascribed to its larger pore volume than that of compound 1.