Modelling of photochemical water splitting based on charge accumulation in macrocycles

使用均相催化剂的光化学水分解为可持续制氢提供了一种概念上简单而有前途的途径。这个过程的核心是分子光敏剂和催化剂。虽然这样的光氧化还原催化系统在合成化学的其他领域已经建立，但光催化水分解需要一个多电子过程，其中几个电子积聚在一个分子单元中，这是一个特别的挑战。最近开发的一类基于对环phanetetraene的大环为可以积累多个电荷的分子系统提供了一个有希望的新范例，其中多个电荷可以通过大环中全局芳构性的发生而稳定。他们在多电子光氧化还原催化中的应用正在由帝国理工学院和拉夫堡大学合作进行的EPSRC项目EP/V048686/1中进行研究。这个项目的目的是通过详细的计算研究来支持这些努力。计算不仅可以预测氧化还原电位，还可以详细了解大环中全局芳构性发生的电子结构。最近开发的高效动力学方法将允许以前所未有的细节研究所需的电荷分离过程。该项目将研究原型大环催化剂，将其与现有光氧化还原催化剂的性能进行对比，并提出新的候选催化剂。成果-通过均相催化光化学水分解的详细机理研究-新催化剂的开发

Photochemical water splitting using homogeneous catalysts provides a conceptually simple and promising route towards sustainable hydrogen production. At the heart of this processes lies a molecular photosensitizer along with a catalyst. Whereas such photoredox catalytic systems are well-established in other areas of synthetic chemistry, it is a particular challenge that photocatalytic water splitting requires a multielectron process where several electrons are accumulated in one molecular unit.A promising new paradigm for molecular systems that can accumulate several charges is provided by a class of recently developed macrocycles based on paracyclophanetetraene, where multiple charges can be stabilized with the occurrence of global aromaticity in the macrocycle. Their use in multielectron photoredox catalysis is being investigated in the on-going EPSRC project EP/V048686/1 in collaboration betweenImperial College and Loughborough. It is the purpose of this project to support these efforts with detailed computational studies. Computations will not only predict redox potentials but will give detailed insight into the electronic structure involved focussing on the occurrence of global aromaticity in the macrocycle. Recently developed efficient dynamics methods will allow to study the required charge separation processes in unprecedented detail. The project will investigate prototype macrocyclic catalysts, contrast their properties with existing photoredox catalysts and suggest new candidates.Deliverables-Detailed mechanistic insight into photochemical water splitting via homogeneous catalysis-Development of new catalysts