The uranyl ion (UO₂²⁺; U(vi) oxidation state) is the most common form of uranium found in terrestrial and aquatic environments and is a central component in nuclear fuel processing and waste remediation efforts. Uranyl capture from either seawater or nuclear waste has been well studied and typically relies on extremely strong chelating/binding affinities to UO₂²⁺ using chelating polymers^1,2, porous inorganic^3,4,5 or carbon-based^6,7 materials, as well as homogeneous⁸ compounds. By contrast, the controlled release of uranyl after capture is less established and can be difficult, expensive or destructive to the initial material^2,9. Here we show how harnessing the redox-switchable chelating and donating properties of an ortho-substituted closo-carborane (1,2-(Ph₂PO)₂-1,2-C₂B₁₀H₁₀) cluster molecule can lead to the controlled chemical or electrochemical capture and release of UO₂²⁺ in monophasic (organic) or biphasic (organic/aqueous) model solvent systems. This is achieved by taking advantage of the increase in the ligand bite angle when the closo-carborane is reduced to the nido-carborane, resulting in C–C bond rupture and cage opening. The use of electrochemical methods for uranyl capture and release may complement existing sorbent and processing systems.

铀酰离子（UO ₂ ²⁺；U( vi ) 氧化态）是在陆地和水生环境中发现的最常见的铀形式，是核燃料加工和废物修复工作的核心成分。从海水或核废料中捕获铀酰已得到充分研究，通常依赖于使用螯合聚合物^1,2、多孔无机^3,4,5或碳基^6,7材料对 UO ₂ ²⁺的极强螯合/结合亲和力，以及同质的⁸种化合物。相比之下，铀酰在捕获后的控制释放不太确定，并且可能很困难、昂贵或对初始材料具有破坏性^2,9。在这里，我们展示了如何利用邻位取代的closo -carborane (1,2-(Ph ₂ PO) ₂ -1,2-C ₂ B ₁₀ H ₁₀ ) 簇分子的氧化还原可切换螯合和供体特性来实现UO ₂ ²⁺在单相（有机）或双相（有机/水）模型溶剂系统中的受控化学或电化学捕获和释放。这是通过利用在近碳硼烷还原为nido时配体咬合角的增加来实现的-碳硼烷，导致 C-C 键断裂和笼子打开。使用电化学方法捕获和释放铀可以补充现有的吸附剂和处理系统。