Bespoke Bimetallics for Chemical Cooperativity

英国化工和制药行业的重要性可以从一个统计数据中看出：它每个工作日为我们的国内生产总值(GDP)提供6000万GB的附加值(相当于每年150亿GB)。GDP是一个国家一年提供的商品和服务的总价值。尖端研究、创新和可持续性是该项目的核心。这项研究是在有机金属化学领域进行的，这是化学的一个核心领域，在现实世界的无数应用中得到了应用，横跨化学和其他学科，如生物化学和材料科学。有机金属化合物由有机部分和金属部分组成，是构建大小分子的基本工具。已知的化学过程有很大一部分依赖于有机金属化合物的金属部分，有机金属化合物是一种贵重的过渡金属(通常是钯、铂、铑、铱、Ru和Os)，它们对从农用化学品到药品(特别是抗癌药物)的许多特种化学品的制造都是必不可少的。贱(非贵金属)通常要便宜得多(因为它们的自然丰度更高)，并且反映出地壳中的高丰度，它们比贵金属对应的金属具有更少的毒性。问题是，它们的化学反应(它们有效地进行有用反应的能力)受到比较的限制，所以它们在许多化学过程中往往效率低下。如果贱金属化学能够发展到贵金属过渡金属化学的状态，或者更好地超越这种状态，那么可持续性将显著提高，对环境不那么友好的贵金属过渡金属的依赖将减少。研究小组最近的进展表明，通过制备含有两种贱金属元素而不是一种贱金属元素的有机金属化合物，可以使贱金属化学的效率提高一个数量级。所有这些金属对共有的金属是碱金属(锂、钠或钾)，而第二种金属是镁、锌、铝或富含地球的过渡金属铁和锰。通过形成在单一金属系统中不可能形成的混合金属双金属结构，诱导了合作效应，从而改变了贱金属的反应性，开辟了大量目前仅凭贱金属本身无法实现的新反应。在我们的目标C-C键的形成和通过碱金属-Fe或-Mn对C-F键的激活中，协同性将特别重要，因为目前这些反应通常是贵金属过渡金属催化的领域。实现可持续贱金属化学的这种升级本身将是一个重大突破，但这个项目将面临另一个雄心勃勃的挑战。碱金属有机金属化学总是需要在厌氧条件下进行，因为所涉及的化合物在空气或湿气的痕迹下迅速分解。然而，该团队最近发现，某些有机碱金属反应可以在有氧条件下使用深度共晶溶剂(DES)进行，而不是使用工业标准的经典有机溶剂。与有机溶剂相比，DES更具成本效益、更环保、可生物可再生，改用它们还将消除对昂贵的惰性大气协议的需求。DES的概念验证结果是单一贱金属，因此挑战是在DES中开发这种新的双金属化学。这项研究的成功将对世界范围内的有机金属化学实践产生影响。

The importance of the UK's chemical and pharmaceutical sector can be seen in the statistic that it supplies £60M of added value each working day (that equates to £15bn a year) to our Gross Domestic Product (the total value of goods and services provided by a country in one year). Cutting edge research, innovation and sustainability lie at the heart of this project. The research is in organometallic chemistry, a core area of chemistry that is utilised in a myriad of real world applications, spanning chemistry and other disciplines such as biochemistry and material science. Organometallic compounds, comprising an organic moiety and a metal moiety are essential tools for constructing molecules big and small. A large proportion of known chemical processes depend on the metal moiety of organometallic compounds being a precious transition metal (commonly palladium, platinum, rhodium, iridium, ruthenium, and osmium), which are essential for the manufacture of numerous specialty chemicals from agrochemicals through to pharmaceuticals (especially anticancer drugs).Base (non-precious) metals are generally much cheaper (due to their higher natural abundance) and reflecting this high abundance in the earth's crust they have less toxicity concerns than their precious metal counterparts. The problem is their chemistry (their ability to carry out useful reactions efficiently) is rather limited by comparison so more often than not they are inefficient in many chemical processes. If base metal chemistry could be developed to the status of precious transition metal chemistry or better still to go beyond this status, then sustainability would be significantly improved and reliance on less environmentally benign precious transition metals would be reduced.Recent advances by the research team have demonstrated that base chemistry can be made orders of magnitude more efficient by preparing organometallic compounds that contain two base metal elements instead of one. The metal common to all of these metal pairs is an alkali metal (lithium, sodium or potassium), while the second metal is magnesium, zinc, aluminium or the earth-abundant transition metals iron and manganese. By forming mixed-metal bimetallic structures impossible in single-metal systems, cooperative effects are induced which transform the reactivity of the base metals opening up a vast number of novel reactions that are currently inaccessible to base metals on their own. Cooperativity will be especially important in our targeted C-C bond formations and C-F bond activations through alkali metal -Fe or -Mn partnerships as currently these reactions are generally the domain of precious transition metal catalysis. Realising this escalation of sustainable base metal chemistry will be a major breakthrough in itself but this project will take on an additional ambitious challenge. Alkali metal organometallic chemistry invariably needs to be performed under anaerobic conditions as the compounds involved rapidly decompose with even traces of air or moisture. However, the team recently made the extraordinary finding that certain organoalkali metal reactions could be run under aerobic conditions by using Deep Eutectic Solvents (DES) as opposed to industry standard classical organic solvents. DES are more cost-effective, greener and biorenewable than organic solvents and switching to them would also do away with the need for costly inert atmosphere protocols. The proof of concept results with DES have been with single base metals, so the challenge is to develop this new bimetallic chemistry in DES. Success will impact the practice of organometallic chemistry worldwide.