FLP Zintl Clusters for the Electrochemical Catalytic Reduction of Small Molecules

用于小分子电化学催化还原的 FLP Zintl 簇

• 批准号: 2466112
• 金额: --
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2466112
• 关键词: FLP; Zintl; Clusters; Electrochemical; Catalytic; FLP; Zintl; Clusters; Electrochemical; Catalytic

We will harness the untapped reactivity of Zintl ions, polayanionic clusters of earth abundant main-group elements, to affect small molecule activations in stoichiometric and catalytic fashions. Coupling reactions to yield new bonds, especially C-C bonds, occupy a central position in synthetic chemistry. To this end, a rich history of Pd cross-coupling reactions exploited by both academic and industrial chemists has developed. However, the high operational costs and toxicity of metal-based catalysts has spurred an interest in main-group systems that can represent this reactivity. Perhaps the most diverse and successful examples of main-group catalysts are frustrated Lewis pairs (FLPs). Traditional FLP systems rely on a Lewis acidic and a Lewis basic site to activate small molecules, and most homoatomic and heteroatomic bond formation reactions are accessed by bond polarisation mechanisms. However, the scope of these bond formation reactions remains limited and C-C bond formation with CO2 remains unidentified in the field. In this project, a new family of FLPs consisting of clusters capable of multi-site activation will be coupled with electrochemical methods to promote bond formation chemistries.We intend to establish Zintl clusters as the basic component in FLP chemistry. Preliminary investigations are targeted with [P7]3-, not only because of its synthetic accessibility, presence of an NMR handle, and greater stability relative to group 14 clusters, but also because of the wide-spread success of phosphines as the basic component in established FLP systems. Once functionalised with an acidic component, these polyanionic clusters are excellent targets for small molecule activation via a FLP pathway, as they feature both the necessary electron-rich and electron-poor components. With this proximity and the propensity to undergo redox reactions in mind, these systems will be assessed in the electrochemical reduction of small molecules, our most ambition target would be the selective reduction of CO2 to ethane. Recycling the C1 building-block, environmental toxin, and industrial by-product into value-added products reminiscent of the fuels from which CO2 is generated upon combustion.This research project will be collaboratively undertaken by the Mehta and Dryfe groups, and has been divided into two work packages.Work Package 1 (primarily based in the Mehta group):1. Functionalise the group 15 Zintl clusters, namely [P7]3-, with a Lewis acidic component2. Perform insertion chemistry between acidic and basic centres on these clusters akin to FLP chemistry. Small molecules of particular interest include CO2, olefins, carbonyls, carbodiimides, and isocyanates.PhD project call 20203. Reductively couple activated substrates to form new bondsWork Package 2 (primarily based in the Dryfe group):4. Immobilise FLP Zintl material on suitable electrode surfaces, e.g. glassy carbon or edge-plane pyrolytic graphite5. Electrochemically close catalytic cycles by reducing the expected oxidatively coupled cluster product6. Use kinetic analysis methods to determine, and optimise, rates of catalytic processes via fitting of electrochemical data.Zintl clusters capture the imagination of academics because they are molecular models for larger heterogenous systems. Technology we develop with [P7]3- can be expanded to larger polyphosphides, such as [P11]3-, [P16]2-, [P21]3-, and eventually inform reactivity possible with functionalised red phosphorus. The strategy of electrochemically / photochemically converting CO2 to reduced value-added products is referred to as artificial photosynthesis.

我们将利用Zintl离子（地球丰富的主元素的polayanionic簇）的未开发的反应性，以影响化学计量和催化时尚中的小分子激活。产生新键，尤其是C-C键的耦合反应在合成化学中占据了中心位置。为此，学术和工业化学家所利用的PD交叉偶联反应的丰富历史已经发展。但是，基于金属的催化剂的高运营成本和毒性激发了对可以代表这种反应性的主体系统的兴趣。也许主要的主体催化剂的最多样化和成功的例子是沮丧的刘易斯对（FLPS）。传统的FLP系统依靠刘易斯酸性和刘易斯基本位点激活小分子，并且大多数同种子和杂色键的形成反应是通过键极化机制访问的。但是，这些键形成反应的范围仍然有限，并且与CO2的C-C键形成在现场仍然不明。在这个项目中，由能够多站点激活的簇组成的新FLP家族将与电化学方法结合起来，以促进键形成化学。初步研究的目标是[P7] 3-，这不仅是因为其合成的可及性，NMR手柄的存在以及相对于第14组群集的稳定性更高，而且还因为磷在已建立的FLP系统中的基本成分取得了广泛的成功。一旦用酸性成分官能化，这些聚苯式簇是通过FLP途径激活小分子的绝佳靶标，因为它们具有必要的富含电子和电子贫乏的成分。考虑到这种接近性和考虑到氧化还原反应的倾向，这些系统将在小分子的电化学降低中进行评估，我们最大的野心目标是将CO2的选择性减少到乙烷。将C1建筑块，环境毒素和工业副产品回收到增值产品中，让人联想到燃烧时二氧化碳生成的燃料。这项研究项目将由Mehta和Dryfe组进行，并已将两个工作套餐分为两个工作套件。功能化15组的Zintl簇，即[P7] 3-，用刘易斯酸性分子2。在类似于FLP化学的这些簇上进行酸性和基本中心之间的插入化学。特别感兴趣的小分子包括二氧化碳，烯烃，羰基，碳纤维酰亚胺和异氰酸酯。PHD项目致电20203。还原性夫妇激活的基板以形成新的债券工作包2（主要基于Dryfe Froup）：4。将FLP Zintl材料固定在合适的电极表面上，例如玻璃碳或边缘平面热解石墨5。通过减少预期的氧化耦合簇产物6来关闭电化学上的催化循环6。使用动力学分析方法通过拟合电化学数据来确定并优化催化过程的速率。Zintl簇捕获了学者的想象，因为它们是用于较大异源系统的分子模型。我们使用[P7] 3-开发的技术可以扩展到较大的多磷化物，例如[P11] 3-，[P16] 2-，[P21] 3-，并最终通过功能化的红磷提供了反应性。电化学 /光化学上将二氧化碳转换为降低的增值产品的策略称为人工光合作用。