Light-Driven Charge Accumulation Based on Earth-Abundant High-Potential Photosensitizers (CA-HiPoPS)

基于地球丰富的高电位光敏剂的光驱动电荷积累（CA-HiPoPS）

• 批准号: 501188872
• 负责人: Professorin Dr. Katja Heinze
• 金额: --
• 依托单位: Laboratoire de Chimie et Physique Quantiques - UMR5626
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/501188872?language=en
• 关键词: Light; Driven; Charge; Accumulation; Based

Photoinduced electron transfer is an elementary reaction step of natural photosynthesis and as such plays a key role in the conversion of sunlight into biological matter. The transfer of single electrons is nowadays fairly well understood, but the transfer and accumulation of multiple electrons has remained extremely challenging. Artificial photosynthesis crucially relies on multi-electron transfer reactions, because the conversion of low-energy input molecules into higher-energy products intrinsically involves multiple redox events. Against this background, this consortium will develop new concepts for the light-driven accumulation of multiple redox equivalents to unravel its basic operating principles. We aim to make three conceptual key advances: (1) We will use new photosensitizers made from abundant transition metals featuring higher reducing power than well-known precious metal-based photosensitizers; (2) We will develop new molecular electron storage units that help us exploit the concept of redox potential inversion to facilitate the light-driven accumulation of redox equivalents; (3) We will use state-of-the-art two-pulse two-color pump-pump-probe UV-Vis absorption spectroscopy to monitor the consecutive transfer of multiple electrons. The first project phase will focus on high-potential photosensitizer (HiPoPS) design and development based on molybdenum(0) complexes, guided by computational chemistry. The second project phase will concentrate on synthesis, photochemical characterization and theoretical understanding of novel photosensitizer-acceptor (PS-A) dyads with acceptors capable of storing up to two electrons, e. g. the well-known naphthalene diimide acceptor, in which the primary reduction is thermodynamically easier to perform than secondary reduction. In parallel, the second project phase will develop and explore new types of electron acceptors featuring redox potential inversion. The new acceptors (TTP; 4,5,9,10-tetrathiapyrene and TBP, [1,1’:4’,1’’-terphenyl]-2,2’,2’’,5’-bis(dithiin)) will be able to accumulate and store up to four redox equivalents, and they will be covalently connected with two HiPoPS units giving PS-A-PS triads. The third project phase targets fully integrated (all-covalent) molecular pentads D-PS-A-PS-D comprised of two peripheral TMPD (N,N,N’,N’-tetramethyl-p-phenylene diamine) donors D connected via two Mo0 HiPoPS to a central TTP acceptor unit A. The three involved teams offer complementary expertise in polypyridine ligand and metal complex design, isocyanide chelates, and computational tailoring of long-lived MLCT excited states in 4d6 metal complexes. The three involved teams share complementary backgrounds and expertise in photoinduced electron transfer reactivity, encompassing bioinspired coupled electron and proton transfer, theoretical aspects of excited-state charge transfer processes, and light-driven charge accumulation in molecular systems.

光诱导电子转移是自然光合作用的基本反应步骤，因此在将阳光转化为生物物质的过程中起着关键作用。如今，单电子的转移已被很好地理解，但多电子的转移和积累仍然极具挑战性。人工光合作用关键依赖于多电子转移反应，因为低能量输入分子转化为高能量产物本质上涉及多个氧化还原事件。在此背景下，该联盟将开发光驱动累积多个氧化还原当量的新概念，以阐明其基本操作原理。我们的目标是在概念上取得三个关键进展：（1）我们将使用由丰富的过渡金属制成的新型光敏剂，其还原能力比众所周知的贵金属基光敏剂更高； （2）我们将开发新的分子电子存储单元，帮助我们利用氧化还原电位反转的概念来促进光驱动的氧化还原当量的积累； (3)我们将使用最先进的双脉冲双色泵浦探针紫外-可见吸收光谱来监测多个电子的连续转移。项目第一阶段将重点关注计算化学指导下基于钼（0）配合物的高电位光敏剂（HiPoPS）的设计和开发。项目第二阶段将集中于新型光敏剂-受体（PS-A）二元组的合成、光化学表征和理论理解，其中受体能够存储最多两个电子，例如电子。 g。众所周知的萘二酰亚胺受体，其中初级还原在热力学上比次级还原更容易进行。与此同时，项目第二阶段将开发和探索具有氧化还原电位反转功能的新型电子受体。新的受体（TTP；4,5,9,10-四硫芘和TBP，[1,1':4',1''-三联苯]-2,2',2'',5'-双（二硫因））将能够积累和存储多达四个氧化还原当量，并且它们将与两个HiPoPS单元共价连接，形成PS-A-PS三联体。第三项目阶段的目标是完全集成的（全共价）分子五联体 D-PS-A-PS-D，由两个外围 TMPD（N,N,N',N'-四甲基对苯二胺）供体 D 通过两个 Mo0 HiPoPS 连接到中心 TTP 受体单元 A 组成。三个参与的团队在聚吡啶配体和金属配合物设计方面提供互补的专业知识， 异氰化物螯合物，以及 4d6 金属配合物中长寿命 MLCT 激发态的计算定制。三个参与团队在光诱导电子转移反应性方面拥有互补的背景和专业知识，包括生物启发的耦合电子和质子转移、激发态电荷转移过程的理论方面以及分子系统中光驱动的电荷积累。