EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3JJ, UK.
Nat Chem. 2012 Feb 21;4(3):221-7. doi: 10.1038/nchem.1270.
The most common motif in uranium chemistry is the d(0)f(0) uranyl ion UO(2) in which the oxo groups are rigorously linear and inert. Alternative geometries, such as the cis-uranyl, have been identified theoretically and implicated in oxo-atom transfer reactions that are relevant to environmental speciation and nuclear waste remediation. Single electron reduction is now known to impart greater oxo-group reactivity, but with retention of the linear OUO motif, and reactions of the oxo groups to form new covalent bonds remain rare. Here, we describe the synthesis, structure, reactivity and magnetic properties of a binuclear uranium-oxo complex. Formed through a combination of reduction and oxo-silylation and migration from a trans to a cis position, the new butterfly-shaped Si-OUO(2)UO-Si molecule shows remarkably strong U(V)-U(V) coupling and chemical inertness, suggesting that this rearranged uranium oxo motif might exist for other actinide species in the environment, and have relevance to the aggregation of actinide oxide clusters.
铀化学中最常见的主题是 d(0)f(0)铀酰离子UO(2)，其中氧基团严格呈线性且惰性。理论上已经确定了替代的几何形状，例如顺式铀酰，并且与环境形态和核废料修复中的氧原子转移反应有关。单电子还原现在被认为赋予了更大的氧基团反应性，但保留了线性 OUO 主题，并且氧基团形成新的共价键的反应仍然很少见。在这里，我们描述了双核铀-氧络合物的合成、结构、反应性和磁性。通过还原和氧硅烷基化的组合以及从反式到顺式位置的迁移形成，新的蝶形 Si-OUO(2)UO-Si 分子显示出非常强的 U(V)-U(V)偶联和化学惰性，这表明这种重排的铀氧基可能存在于环境中的其他锕系元素物种中，并且与锕系氧化物簇的聚集有关。
