Modelling of photochemical water splitting based on charge accumulation in macrocycles

使用均相催化剂的光化学分解水提供了一条概念上简单且前景看好的可持续制氢途径。这一过程的核心是分子光敏剂和催化剂。虽然这种光催化体系在合成化学的其他领域中已经得到了很好的应用，但光催化分解水需要一个分子单元中积累多个电子的多电子过程，这是一个特别具有挑战性的问题。最近发展起来的一类基于对环芳四烯的大环为分子体系提供了一个很有前途的新范例，其中多个电荷可以随着大环中全局芳香性的出现而稳定下来。帝国理工学院和拉夫堡大学正在进行的EPSRC项目EP/V048686/1正在研究它们在多电子光氧化还原催化中的应用。这个项目的目的是通过详细的计算研究来支持这些努力。计算将不仅预测氧化还原电位，而且将详细地洞察所涉及的电子结构，重点关注大循环中全局芳香性的发生。最近发展起来的高效动力学方法将使我们能够对所需的电荷分离过程进行前所未有的详细研究。该项目将研究大环催化剂的原型，将它们的性能与现有的光氧化还原催化剂进行比较，并推荐新的候选催化剂。成果-均相催化光化学分解水的详细机理洞察-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