A-Nor: New Concepts for the Norbornadiene/Quadricyclane (NBD/QC) Interconversion

对于未来MOST系统的设计和优化，精确的化学微调以及对光化学异构化机制的全面了解是非常重要的。因此，有针对性地合成新的降冰片二烯/四环（NBD/QC）衍生物，开发高效且前所未有的催化触发能量释放工艺。基于NBD/QC互转化偶对，以及发色团-最色团杂化结构，我们的目标是优化分子结构和系统特性，以便接近竞争性的MOST应用，同时对潜在的光异构化和能量释放过程的基本机制产生新的见解。为此目的，我们的建议将包括三个工作包。工作包1的重点是生成一个新的NBD/QC偶对及其相关的杂环类似物库，这些杂环类似物在桥中含有氧或氮。因此，重点是对NBD/QC对进行定制化功能化，以获得优化的光物理性质，这是未来应用所必需的。合成新型乙烯-降冰片二烯杂化结构作为全光可切换系统的模型化合物是工作包2的任务。这将有助于揭示基本的开关过程，并对潜在的光物理机制产生全面的理解，从而允许对NBD/QC偶联的相关性质进行精确的化学调整。在工作包3中，将研究从NBD到QC的[2+2]光循环以及在壳-壳功能化纳米颗粒及其在双层中的受限空间内的催化反转化。因此，定制的功能化纳米颗粒将被用作a)准均相催化剂，b)提供可调节的密闭空间反应场景的平台，以及c)作为相转移介质，例如允许在水溶液中操作。通过认真处理所提出的工作包，将调查三个主要的研究问题：(i)我们如何设计和优化NBD/QC对，使其成为适合的MOST系统，合成成本低，反应程序高效？（ii）我们如何实现基本的机制理解，以揭示限制相关MOST属性（如能量存储密度）的关键因素？（iii）我们如何才能最大限度地提高由定制的纳米颗粒催化剂触发的催化能量释放的效率，将这种系统用于实际应用的主要挑战是什么？作为FOR MOST的重要组成部分，我们的项目将通过提供一系列基于降冰片二烯的新型储能系统、用于研究基本机理的模型化合物和触发能量释放反应的纳米颗粒催化剂，推动未来MOST技术的发展。

For the design and optimization of future MOST systems, precise chemical fine-tuning as well as comprehensive understanding of the photochemical isomerization mechanism is of major importance. Therefore, the syntheses of new norbornadiene/quadricyclane (NBD/QC) derivatives and the development of efficient and unprecedented catalytically triggered energy release processes is targeted. Based on the NBD/QC interconversion couple, as well as chromophore-mostophore hybrid structures, our goal is to optimize the molecular architectures and system properties in order to approach competitive MOST applications while simultaneously generating new insights into the fundamental mechanistics of the underlying photoisomerization and energy release processes. For this purpose, our proposal will consist of three work-packages. The thrust of work-package 1 is to generate a library of new NBD/QC couples and their related heterocyclic analogues containing e.g. oxygen or nitrogen in the bridge. Consequently, the focus is to perform tailored functionalization of NBD/QC couples to obtain optimized photophysical properties, which are necessary for future applications. The synthesis of novel rylene-norbornadiene hybride structures as model compounds for fully photo-switchable systems is the task of work package 2. This will help to unravel the fundamental switching process and generate comprehensive understanding of the underlying photophysical mechanism, thus allowing for precise chemical tuning of the related properties of NBD/QC couples. In work-package 3, both the [2+2] photocyclization from NBD to QC and the catalytic back-conversion within shell-by-shell functionalized nanoparticles and their confined space in the bilayer, will be investigated. Therefore, tailor-made functionalized nanoparticles will be used as a) quasi-homogeneous catalysts, b) platforms providing a tunable confined space reaction scenario and c) as phase-transfer mediators allowing for example to operate in aqueous solutions. Through the conscientious processing of the proposed work-packages, three main research questions will be investigated: (i) How can we design and optimize NBD/QC couples as suitable MOST systems with low synthetic effort and efficient reaction procedures? (ii) How do we implement the fundamental mechanistic understanding to unravel the key factors limiting the relevant MOST properties such as energy storage density? (iii) How can we maximize the efficiency of the catalytic energy release trigged by tailor-made nanoparticle-based catalysts and what are the main challenges by using such systems for practical applications? As essential part within FOR MOST, our project will push forward the future MOST technology by providing a series of novel norbornadiene-based energy storage systems, model compounds for the investigation of fundamental mechanistics and nanoparticle-based catalysts to trigger the energy release reaction.