Structure-control of valence electron isomerism in the f-block

f-嵌段中价电子异构的结构控制

• 批准号: EP/Y006534/1
• 负责人: Conrad Goodwin
• 金额: $ 74.24万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FY006534%2F1
• 关键词: Structure; control; valence; electron; isomerism

The valence electron configuration of a metal describes the relative ordering and properties of the highest-energy electrons - those that are available for bonding with other elements, and thus it is these which largely dictate the physicochemical properties of metal-containing materials. For much of the Periodic Table, some known principles can guide the design criteria needed to produce a given electron configuration of the element in question and result in desirable properties. The oxidation state of the metal - the (formal) number of electrons the metal has lost versus the neutral configuration, and the geometry of bound ligands are two of the most important features which can be controlled. This project seeks to develop the redox chemistry of the lanthanides, and early actinide (thorium, uranium, neptunium, plutonium) elements towards a deeper understanding of the design criteria which dictate the valence electron configurations of these metals in lower oxidation states.Lanthanide and actinide elements (the f-block) occupy a position in the Periodic Table where the valence electrons in metal ions reside in highly angular 4f- and 5f-orbitals, which show poor radial extent and thus the bonding between these elements and others is typically quite weak. It is these characteristics which engender the unique physical properties typical of these metals (e.g. applications in magnetism and optical spectroscopy). Simply, a 3+ metal ion in a molecule may have f n valence electrons, where n is three less than the neutral configuration, and there is little which may be done to change the chemical properties of the remaining f-electrons substantially (though their physics may be altered).Developments the chemistry of f-block redox chemistry over the last 20 years have produced examples of all the lanthanides (except Pm), as well as thorium, uranium, neptunium, and plutonium in the 2+ oxidation state, many of these for the first time. This remarkable pace of advancement has overturned many preconceptions about the redox properties of these elements, but has raised questions that this project seeks to address.For some elements, the valence electron configuration of 2+ ions follows the example above with f n+1 valence electrons where n is three less than the neutral atomic configuration. Samarium, europium and ytterbium are examples of this and are often termed "traditional" 2+ lanthanide ions due to this behaviour. For other elements (such as cerium), all examples of molecular 2+ complexes feature an electron configuration described as: f n d1, where n is still three less than the neutral atomic configuration, and one electron resides in a d-orbital (for cerium 2+: f1 d1). As d-orbitals are fundamentally different to f-orbitals (larger radial extent, more diffuse, different magnetic properties), the physicochemical properties of cerium 2+ molecules (which have two metal valence electrons - f1 d1), should differ substantially from molecules with praseodymium 3+ which also features two metal valence electrons (f2). Some elements such as uranium have been shown to accommodate both types of electron configuration in the 2+ oxidation state: f n+1, and also f n d1. The underlying properties which drive the preference for one configuration over the other are poorly known, and is an under explored topic at the forefront of synthetic chemistry.This project will produce examples across the f-block of metal 2+ compounds, determine their valence electron configurations, and use a combination of magnetic and spectroscopic techniques to identify the properties which direct the formation and stability of specific configurations. These results will have applications in the fields of spintronics and quantum technologies which rely on the control of spins by developing new routes to giant molecular spins, and produce fundamental advances in f-block coordination chemistry foundational to future advances in their reactivities.

金属的价电子构型描述了最高能量电子的相对顺序和特性 - 那些可与其他元素键合的电子，因此很大程度上决定了含金属材料的物理化学特性。对于元素周期表的大部分表，一些已知的原理可以指导产生所讨论元素的给定电子构型所需的设计标准并导致理想的属性。金属的氧化态 - 金属损失与中性构型的（形式）电子数，并且结合配体的几何形状是可以控制的两个最重要的特征。该项目旨在开发兰烷基的氧化还原化学，早期的actacinide（thor，铀，海王星，plutonium）元素，以对设计标准更深入地理解，这些设计标准决定了这些金属在下部氧化状态下这些金属的构型的构造。 4F和5F轨道表现出较差的径向范围，因此这些元素与其他元素之间的键合通常很弱。正是这些特征引起了这些金属典型的独特物理特性（例如磁和光谱中的应用）。 Simply, a 3+ metal ion in a molecule may have f n valence electrons, where n is three less than the neutral configuration, and there is little which may be done to change the chemical properties of the remaining f-electrons substantially (though their physics may be altered).Developments the chemistry of f-block redox chemistry over the last 20 years have produced examples of all the lanthanides (except Pm), as well as thorium,在2+氧化状态下的铀，海王星和p，其中许多是第一次。这种显着的进步速度推翻了有关这些元素的氧化还原特性的许多先入之见，但已经提出了该项目寻求解决的问题。对于某些元素，2+离子的价电子构型遵循上述示例，其中f n+ 1价电子n在n中n比中性原子质构造小三个。 samarium，europium和ytterbium就是这样的例子，由于这种行为，通常被称为“传统” 2+灯笼离子。对于其他元素（例如石），所有分子2+复合物的示例都具有电子构型，称为：f n d1，其中n仍然比中性原子构构少三个，而一个电子位于d-轨道中（对于葡萄干2+：F1 d1）。由于D轨道与F轨道（较大的径向范围，更分散，不同的磁性特性）的根本不同，因此岩性2+分子的理化特性（具有两个金属价电子-f1 d1）应与分子有很大的不同，它与Praseodymium 3+具有两个金属价值（F2）。已经证明，一些元素（例如铀）在2+氧化状态下可容纳两种类型的电子构型：f n+ 1，以及f n d1。推动一种配置而不是另一种配置的偏爱的基本属性是鲜为人知的，并且在合成化学的最前沿是一个受过探索的主题。该项目将在金属2+化合物的F块中产生示例，确定其价值电子配置，并确定磁性和光谱技术的组合，以识别构图的组合，以识别形式和表现性。这些结果将在旋转三位型和量子技术领域具有应用，这些技术依赖于旋转的控制，通过为巨型分子旋转开发新的途径，并在F-block配位化学方面产生基本进步，从而在其反应率中为未来的进步提供了基础。