Organo-Fluoro-Pnictonium Cations: Designing a New Class of Lewis Acid Catalyst

商业合成的有机化学品对农业、医药和电子等多种行业至关重要。面对药物设计和日常技术的创新，如移动的电话和太阳能电池板，全球对这些产品的巨大需求不断增加。与此相反的是，在环境问题和自然资源减少的情况下，越来越需要节约能源和原材料。催化是调和这些相互竞争的需求的一个极其重要的工具。使用催化剂降低了进行特定化学反应的能量障碍，使过程能够在较低的温度和压力下运行，消耗更少的能量。催化剂还可以通过促进新的反应，减少获得最终产品所需的试剂和步骤的数量来提高资源和时间经济性。催化剂在这些过程中不会消耗，而是再生，使其成为可持续合成化学的基石。该项目将为开发低成本，高效和可获得的新催化剂提供所需的基础研究。目前，在商业有机合成中最广泛使用的许多催化剂是基于昂贵的过渡金属如铂、钯、铑和金，其具有低的天然丰度。对新催化剂的研究越来越多地集中在用更便宜的金属取代现有催化工艺中的催化剂。还期望开发用于新工艺的催化剂，从而导致改进的反应途径和新产品。虽然主族元素的简单卤化物长期以来一直用作刘易斯酸催化剂，但这些通常是腐蚀性的并且缺乏任何过渡金属。基于有机金属主族衍生物的催化剂的开发是一个新兴但快速增长的研究领域。近年来的一些重要进展已经挑战了过渡金属对于有机键形成反应的催化是必要的这一想法。主族金属如锑（Sb）和铋（Bi）是丰富和廉价的（比铂便宜20倍以上，例如）。拟议的研究将开发直接的合成路线，以新的分子，包括有机和氟取代的锑和铋阳离子与弱配位阴离子。基于以前的工作，这些分子有潜力成为良好的催化剂，有机转化，因为它们的可调的刘易斯酸性和明确的空结合位点。到目前为止，重主族金属的有机化合物的研究远远少于过渡金属的有机化合物，而对Sb和Bi的有机氟化物的研究特别有限，尽管这些有希望的属性。该项目的一个重要成果是了解这些类型化合物的基本化学和键合，并确定生产它们的最有效方法。研究它们与刘易斯碱和小有机分子的反应性将有助于确定潜在的催化剂，这些催化剂将根据一组关键反应的测试进行筛选。建立控制主族有机金属分子与有机基质相互作用的基本化学对于长期减少全球对昂贵过渡金属催化剂的依赖至关重要。

Commercially synthesised organic chemicals are crucial to industries as diverse as agriculture, medicine and electronics. The enormous global demand for these products is constantly rising in the face of innovations in drug design and everyday technology, such as mobile phones and solar panels. Set against this is the increasingly important need to conserve energy and raw materials, in the context of environmental concerns and diminishing natural resources. Catalysis is an extremely important tool in reconciling these competing demands. Using a catalyst lowers the energy barrier to carry out a given chemical reaction, allowing processes to function at lower temperatures and pressures, consuming less energy. Catalysts can also improve resource and time economy by promoting new reactions, reducing the number of reagents and steps required to obtain an end product. Catalysts are not consumed in these processes, but regenerated, making them a keystone of sustainable synthetic chemistry. This project will provide the fundamental research needed for development of low cost, efficient and accessible new catalysts. Currently, many of the catalysts most widely used in commercial organic synthesis are based on costly transition metals such as platinum, palladium, rhodium and gold, which have low natural abundance. Research into new catalysts is increasingly focused on replacing these with cheaper metals in existing catalytic processes. It is also desirable to develop catalysts for new processes, leading to improved reaction pathways and new products. While simple halides of main group elements have long been used as Lewis acid catalysts, these are generally corrosive and lack any tuneability. The development of catalysts based on organometallic main group derivatives is a nascent but rapidly growing area of study. Several important advances in recent years have challenged the idea that transition metals are necessary for the catalysis of organic bond forming reactions. Main group metals such as antimony (Sb) and bismuth (Bi) are abundant and inexpensive (more than 20 times cheaper than platinum, for example). The proposed research will develop straightforward synthetic routes to new molecules comprising organic and fluoride substituted Sb and Bi cations with weakly coordinating anions. Based on previous work, these molecules have the potential to be good catalysts for organic transformations because of their tuneable Lewis acidity and well-defined vacant binding sites. Organometallic compounds of heavy main group metals have until now received far less study than those of transition metals, and research into the organic fluorides of Sb and Bi has been particularly limited, despite these promising attributes. An important outcome of this project will be to understand the fundamental chemistry and bonding of these types of compound, and determine the most efficient ways to produce them. Investigation of their reactivity with Lewis bases and small organic molecules will help to identify potential catalysts which will be screened against a test set of key reactions. Establishing the basic chemistry governing the interaction of main group organometallic molecules with organic substrates is essential to reducing global dependence on expensive transition metal catalysts in the long term.