UNCLE: Uranium in Non-Conventional Ligand Environments

元素周期表主要由金属组成，因此对金属-金属键的研究对于改变我们对化学键、催化、金属表面化学和磁性的理解是基本的。锌-锌和镁-镁单键以及四重Re-Re和五重铬-铬键的发现就是一个例证。事实上，过渡金属-过渡金属键现在无处不在。然而，尽管理论预测了非常新颖的成键方式，但含有共价铀-金属键的铀配合物仅限于重烷基铀-锡键。这一创新项目将建立在我们的第一个铀-镓键的初步结果的基础上，从而显著和快速地扩大共价铀-M键(M=过渡金属或铀)。在这些络合物中，金属充当铀的“非常规”配体，这是新的，因为铀化学由更传统的碳基、氮基、氧基或卤化基配体主导。新的铀-金属络合物将接受详细的结构、光谱和理论审查，以全面确定它们的稳定性、结构、成键和反应性。早期金属化学和晚期金属化学的这种联系将使我们：i)更好地理解元素周期表底部的化学键；ii)在小分子活化化学中硬金属和软金属合作的协同效用；iii)对落后于元素周期表其他部分的鳗系元素化学做出快速和重大的贡献。研究铀如何成键，以及它与稀土元素的对比，是模拟高放射性钚和钚的行为和提取的关键，这些元素的放射性太强，无法在常规实验室处理，但它们存在于核废料中。此外，通过将铀直接键合到可以激活碳-氢、碳-氧或氢-氢键的过渡金属上，可以在硬氧化态和软氧化态之间穿梭，我们的目标是制造能够以选择性和原子/能源高效的方式精制工业氯素原料的协同络合物。这个项目是冒险的，极有可能产生对镧系元素和榄系元素化学具有国际意义的结果。

The periodic table is composed mainly of metals, thus the investigation of metal-metal bonds is fundamental to generating step-changes in our understanding of chemical bonding, catalysis, metal surface chemistry, and magnetism. This is exemplified by the discovery of zinc-zinc and magnesium-magnesium single bonds and quadruple rhenium-rhenium and quintuple chromium-chromium bonds. Indeed, transition metal-transition metal bonds are now ubiquitous. However, uranium complexes containing covalent uranium-metal bonds are limited to a 'heavy alkyl' uranium-tin bond even though theory predicts highly novel bonding manifolds. This innovative project will build on our preliminary result of the first uranium-gallium bond to deliver a significant and rapid expansion of covalent uranium-M bonds (M = transition metal or uranium). In these complexes the metal is acting as a 'non-conventional' ligand to uranium, which is novel because uranium chemistry is dominated by more traditional carbon-, nitrogen-, oxygen-, or halide-based ligands. The new uranium-metal complexes will be subjected to detailed structural, spectroscopic and theoretical interrogations in order to comprehensively establish their stability, structure, bonding, and reactivities. This nexus of early- and late-metal chemistry will give us: i) a greater understanding of chemical bonding at the foot of the periodic table; ii) the synergic utility of cooperating hard and soft metals in small molecule activation chemistry; iii) a rapid and significant contribution to actinide chemistry, which lags behind the rest of the periodic table. Studying how uranium bonds, and how it contrasts to lanthanide elements, is key to modelling the behaviour and extraction of highly radioactive plutonium and neptunium, which are too radioactive to handle in conventional laboratories, but which are present in nuclear waste. Additionally, by bonding uranium, which may shuttle between hard and soft oxidation states, directly to transition metals which can activate carbon-hydrogen, carbon-oxygen, or hydrogen-hydrogen bonds we aim to produce synergic complexes which can elaborate industrial C1 feedstocks in selective and atom/energy efficient ways. This project is adventurous and highly likely to generate results of international significance to lanthanide and actinide chemistry.