SubVAR - Sub-Valent Alkaline Earth Reagents

我们的社会依赖于化学工业生产的材料，协助和维持我们的现代生活方式。基于相对简单的化学转化的制造工艺负责药物、杀虫剂、燃料和肥料的生产，并且这些工艺通常围绕基本的构建单元（例如氢气、一氧化碳和氮气）构建。一个典型的例子是费-托（FT）工艺，其是最流行的气-液工艺之一，用于由一氧化碳和氢气生产长链烃。其国家战略重要性体现在英国公司（例如约翰逊万丰、BP、Velocys）在开发新催化剂和FT反应器方面的重大投资，以将城市废物和生物质转化为可再生燃料，这符合英国政府到2030年增加FT工厂数量和合成燃料供应的战略。然而，与这些类型的化学制造工艺相关的成本通常非常高，因为它们通常依赖于昂贵且有毒的过渡金属试剂，并且需要非常高的温度和压力，地球上丰富且无毒的金属为化学制造工艺提供了更便宜和更可持续的替代品。然而，基于这些金属的试剂不能分解这些过程中使用的许多小分子，因为它们缺乏氧化还原反应性。尽管如此，近年来，已经有许多发展的氧化还原活性第2族试剂的产生，导致第一个单价铍，镁和钙物种的报告。这一领域仍处于起步阶段，这些新物种尚未提供与化学工业使用的传统过渡金属系统相当的转化。必须设计新的方法来发现更可持续的替代品和更便宜的试剂，以模拟过渡金属催化剂的性能。该项目将研究碱土金属家族（铍和镭除外）的基本性质;这些是地球上丰富的无毒金属，有朝一日可以为化学工业使用的现有材料提供更可持续的替代品。在初步工作中，我们已经证明单价碱土金属络合物可以通过明智和定制的分子设计来稳定。我们以前的实验和理论研究提供了一个蓝图，是可转移到所有的元素的组，并将提供一类新的物种，其中重碱土金属具有过渡金属样的电子配置，不同于以前的例子的低价第2族配合物。这是制备碱土金属试剂的第一个关键步骤，碱土金属试剂将与合成和催化中使用的经典过渡金属一样具有氧化还原反应性。从根本和应用的角度来看，这一点的影响都很大。第2族元素通常被认为不能像过渡金属那样表现，该项目将提供可行的分子物种的第一个实验证据，其中碱土金属的电子和化学性质将与过渡金属的电子和化学性质平行。由此产生的化合物将能够转化化学工业使用的常见气体（氢气，氮气，一氧化碳），从而为改善化学制造工艺的可持续性开辟新的合成可能性。

Our society relies on the chemical industry for the production of materials that assist and sustain our modern way of life. Manufacturing processes based on relatively simple chemical transformations are responsible for the production of drugs, pesticides, fuels and fertilisers, and it is quite common for these processes to be constructed around fundamental building blocks such as hydrogen, carbon monoxide and nitrogen. A typical example is the Fischer-Tropsch (FT) process, which is one of the most popular gas-to-liquid processes and is used for the production of long chain hydrocarbons from carbon monoxide and hydrogen. Its national strategic importance is demonstrated by the significant investments made by British companies (e.g. Johnson Matthey, BP, Velocys) in the development of new catalysts and FT reactors for the conversion of urban waste and biomass into renewable fuels, which is in line with the UK Government strategy to increase the number of FT plants and synthetic fuel supply by 2030. However, costs associated with these types of chemical manufacturing processes are usually very high, as they often rely on expensive and toxic transition metal reagents, and require very high temperatures and pressures.Earth abundant and non-toxic metals promise cheaper and more sustainable alternatives for chemical manufacturing processes. However, reagents based on these metals cannot break apart many of the small molecules used by these processes because of their lack of redox reactivity. Nonetheless, in recent years there have been many developments towards the generation of redox active Group 2 reagents, leading to the report of the first monovalent beryllium, magnesium and calcium species. This field is still in its infancy and these new species are yet to deliver transformations comparable to those of the traditional transition metal systems used by the chemical industry. New approaches must be devised to discover more sustainable alternatives and cheaper reagents that can mimic the performance of transition metal catalysts. This project will investigate the fundamental properties of the Alkaline Earth family (with the exception of beryllium and radium); these are Earth abundant and non-toxic metals, which could one day provide more sustainable alternatives for current materials employed by the chemical industry.In preliminary work we have demonstrated monovalent Alkaline Earth complexes can be stabilised with judicious and tailored molecular design. Our previous experimental and theoretical studies provide a blueprint that is transferrable to all the elements of the Group and will afford a new class of species in which the heavy Alkaline Earth metals possess transition metal-like electronic configuration, unlike previous examples of sub-valent Group 2 complexes. This is a first crucial step towards the preparation of Alkaline Earth reagents that will perform in redox reactivity in the same vein as classic transition metals employed in synthesis and catalysis. The repercussions of this are significant, both from the fundamental and applicative point of view. Group 2 elements are generally considered unable to behave like transition metals, and this project will provide the first experimental proof of viable molecular species where the electronic and chemical properties of the Alkaline Earth metals will parallel those of transition metals. The resulting compounds will be capable of transforming common gases used by the chemical industry (hydrogen, nitrogen, carbon monoxide), thus opening up new synthetic possibilities for improving the sustainability of chemical manufacturing processes.