Structural control of the electronic coupling between donor and photosensitizer in molecular dyads via modification of a peripheral ligand

通过修饰外围配体对分子二元体中供体和光敏剂之间的电子耦合进行结构控制

• 批准号: 456209398
• 负责人: Professor Dr. Benjamin Dietzek-Ivansic
• 金额: --
• 依托单位: Arbeitsgruppe Molekulare Photonik
• 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/456209398?language=en
• 关键词: Structural; control; electronic; coupling; between

Photoinduced electron transfer is a fundamental process in natural and artificial photosynthesis. Compared to natural photosynthesis, where electron transfer occurs in high yields and leads to the formation of long-lived charge separated states, the synthesis of (supra)molecular structures with specifically controlled electron transfer properties is a challenging and usually iterative process. The targeted synthesis and optimization of molecular donor-acceptor systems with tailor-made properties with respect to of an intramolecular photoinduced electron transfer requires a detailed understanding of the underlying structure-dynamics relationships and in particular the interaction between molecular structure and electronic coupling (|H_DA |^2), reorganization energy (λ) and driving force (〖-∆G〗^*), which are the central parameters for (intramolecular) electron transfer according to the semi-classical Marcus theory. The influence of molecular structure on λ and 〖-∆G〗^* is generally well understood. In contrast, the structural factors determining the electronic coupling |H_DA |^2 between a photosensitizer in the electronically excited state and a donor chemically linked to it are much less intuitive and in general it is challenging to describe the effects of different structural factors on |H_DA |^2 in photoactive transition metal complex dyads in isolation. The aim of this project is to quantitatively determine the electronic coupling |H_DA |^2 for reductive electron transfer from the donor to the photoexcited acceptor for a class of molecular dyads based on a Ru(II)-polypyridine-based photosensitizer (as acceptor) and a covalently linked electron donor. The spectroscopic-theoretical work of this project aims at the systematic deduction of structure-mechanism relationships with respect to the influence of electron transfer by structural modification of the peripheral ligands of the photosensitizers, i.e. the ligands that do not link the photoactive center with the electron donor.

光致电子转移是自然和人工光合作用的一个基本过程。与自然光合作用相比，电子转移发生在高产量并导致形成长寿命的电荷分离态，具有特定控制电子转移性质的（超）分子结构的合成是一个具有挑战性的过程，通常是迭代的过程。在分子内光诱导电子转移方面，有针对性地合成和优化具有定制性质的分子给体-受体系统需要详细了解潜在的结构-动力学关系，特别是分子结构与电子耦合（|H_DA |^2）、重组能（λ）和驱动力（〖-∆G〗^*）之间的相互作用。根据半经典的马库斯理论，这是（分子内）电子转移的中心参数。分子结构对λ和〖-∆G〗^*的影响通常是很清楚的。相比之下，决定电子激发态的光敏剂和与之化学连接的供体之间的电子耦合|H_DA |^2的结构因素要直观得多，总的来说，单独描述不同结构因素对光活性过渡金属复合物中|H_DA |^2的影响是具有挑战性的。本项目的目的是定量确定一类基于Ru(II)-聚吡啶基光敏剂（作为受体）和共价连接电子给体的分子二元体从给体到光激发受体的还原电子转移的电子耦合|H_DA |^2。本项目的光谱理论工作旨在系统地推导光敏剂外围配体（即不连接光活性中心与电子供体的配体）的结构修饰对电子转移的影响的结构-机理关系。