Lanthanides and Actinides in the +1 Oxidation State

元素周期表中约四分之一的元素是镧系元素和氡系元素，统称为f-块元素。这些元素的化学和物理性质对现代社会是不可或缺的。从医学成像、计算机硬盘驱动器和块状磁体到国防技术和光学材料，镧系元素是各种技术应用的核心。放射性元素钍、铀和钚被用于核裂变反应堆，这项技术作为英国净零战略的一部分而被指定为增长的一部分。镧系元素和鳗系元素化合物的化学和物理很大程度上依赖于金属的氧化态。对于镧系元素，氧化态+3是普遍存在的，而含有这些元素的氧化态+2和+4的化合物在有限的情况下是已知的。对于早期的吖系元素，氧化态的范围从+3到+6或+7，最近观察到了高活性的氧化态+2。这个项目将集中于合成和表征第一个含镧系元素和早期一价氧化态(钍-钚)的化合物。PI最近关于第一个铀(I)化合物的报道标志着一系列单价镧系元素和吖系元素化合物的合成和表征。首先，我们专注于一价镧系元素，旨在合成一系列茂金属类夹心化合物，并确定这些不寻常化合物的性质所依赖的因素。同时，我们将合成一价金属茂元素，包括早期的氡系元素钍、铀、铍和钚。该项目的一个核心目标是将合成和结构化学的观察与详细的物理表征和理论研究结合起来。这种方法将提供对单价f元素的电子结构和化学键的定量洞察，包括对离子和共价贡献的描述。结构-性质关系将用于设计反应性研究，重点是使用高度还原的单价f元素进行小分子活化。单价稀土元素的电子结构应该比这些元素在传统氧化态下的电子结构更加多样化。因此，可能会出现相邻稀土元素的反差反应，可能需要对f元素化学的标准描述进行修订。此外，我们将通过与德国同事的新国际合作，通过旨在用我们的科学激励公众的参与活动计划，以及通过参加与科学目标相关的各种培训计划，通过苏塞克斯团队成员的职业发展，将影响嵌入到该项目中。

The lanthanides and actinides, known collectively as the f-block elements, constitute approximately a quarter of the periodic table. The chemical and physical properties of these elements are indispensable to modern society. Lanthanides are at the heart of a huge variety of technological applications, ranging from medical imaging, computer HDDs and bulk magnets, to defence technology and optical materials. The actinides thorium, uranium and plutonium are used in nuclear fission reactors, a technology earmarked for growth as part of the UK's net-zero strategy.The chemistry and physics of lanthanide and actinide compounds depends strongly on the oxidation state of the metal. For the lanthanides, oxidation state +3 is ubiquitous whereas compounds containing these elements in oxidation states +2 and +4 are known in a limited number of cases. For the early actinides, oxidation states range from +3 up to +6 or +7, and the highly reactive oxidation state +2 has recently been observed. This project will focus on the synthesis and characterization of the first compounds containing the lanthanides and the early actinides (thorium-plutonium) in the elusive +1 or monovalent oxidation state.The PI's recent report of the first uranium(I) compound signposts a route to a family of monovalent lanthanide and actinide compounds. At the outset, we focus on monovalent lanthanides, aiming to synthesize a series of metallocene-like sandwich compounds and to determine the factors upon which the properties of these unusual compounds depends. In parallel, we will synthesize monovalent metallocenes of the early actinides thorium, uranium, neptunium and plutonium.A core goal of the project is to combine observations from synthetic and structural chemistry with detailed physical characterization and theoretical studies. This approach will provide quantitative insight into the electronic structure and chemical bonding of monovalent f-elements, including descriptions of the ionic and covalent contributions. The structure-property relationship will be used to design reactivity studies, with an emphasis on small-molecule activation using highly reducing monovalent f-elements. The electronic structure of monovalent lanthanides should be more diverse than for these elements in conventional oxidation states. As a result, contrasting reactivity for neighbouring lanthanides could occur, potentially requiring standard descriptions of f-element chemistry in terms of the lanthanide and actinide contractions to be revised.In addition, we will embed impact into the project through a new international collaboration with colleagues in Germany, through a programme of engagement activities aimed at inspiring the public with our science, and through the career development of the Sussex team members via participation in various training programmes relevant to the scientific objectives.