Unprecedented lead–antimony oxohalide clusters with efficient capture of UO22+ ions

Abstract

The exploration of novel metal–oxo clusters with unique composition and functionality remains an attractive goal in the field of structural chemistry and materials chemistry. By employing a triply synergistic induction strategy that combines ligand induction with the structural tailoring effect of halide anions (I⁻) and lone pair electrons of low-valency p-block metal ions (Pb²⁺ and Sb³⁺ ions), two unprecedented organic ligand-decorated lead–antimony oxohalide cluster compounds have been successfully prepared, namely [(HTEOA)SbOPbI]₄·2H₂O (H₃TEOA = triethanolamine) (1) and (HTEOA)₃Sb₃OPbI₃·CH₃OH (2). 1 features a sandwich configuration formed by two pairs of Sb–L (L = HTEOA) layers and a central [Pb₄O₄I₄] unit. By contrast, 2 represents a crown configuration consisting of a [Sb₃OL₃] base and a [PbI₃] cap. Compound 1 exhibits excellent irradiation stability and high removal capacity for UO₂²⁺ ions, with a rapid kinetics response reaching a removal rate (R^U) of 99.89% within 5 minutes. Even in the presence of high concentrations of competing ions (e.g., Na⁺, Ca²⁺ and Mg²⁺) and in actual water samples, it maintains exceptional selectivity toward UO₂²⁺ with high removal efficiency (distribution coefficient (K^U_d) > 7.42 × 10⁴ mL g⁻¹, R^U > 98.64%). This work not only represents a breakthrough in p-block heterometallic oxohalide cluster chemistry but also expands the potential of antimony oxohalide clusters for radionuclide remediation.