Characterization of Novel Polyhalogen Monoanions

本提案旨在提供各种实验光谱工具，辅以最先进的量子化学计算，指导制备新型多卤阴离子，这些阴离子对研究基体隔离条件具有挑战性但具有指导意义，并有望建立非共价网络。关于所有这些非共价相互作用，有许多重要的问题，比如它们有多强，主要贡献是什么，它们如何随构象变化，以及它们如何受到晶体填充效应的影响等，最后，如何利用这些知识来设计新的结构和应用。主要目标是在基质隔离条件下制备这种新型弱束缚系统，这种系统允许在极低温度（<20 K）下对有效隔离的分子系统（伪气相条件）进行严格的时间无关光谱表征。从足够简单但极具挑战性的系统中获得的实验结果，如[F5]-， [Cl5]-和类似的卤化物对偶物，如[F(Cl2)2]-, [Cl(Br2)2]-, [F(Br2)2]-，将发展我们对这些富电子系统中非共价相互作用的理解，并将用于验证最先进的量子化学计算。除了对有效分离的分子种类进行光谱分析外，我们还打算大量制备新的多卤素单阴离子，如[Cln]-；n=5,7,9和新的卤素间单阴离子如[F(Br2)2]-或[Cl(Br2)2]-。这个子项目将阐明从孤立的分子物种到溶液中的大量分子，以及在固态中扩展网络的转变。新物质的制备将以多种现有的光谱技术为指导，如低温红外、紫外/可见、原位拉曼光谱，以及单晶x射线结构测定，并将结合高水平量子化学研究探索其潜在的应用前景。

The present proposal aims at providing a variety of experimental spectroscopic tools comple-mented by state-of-the-art quantumchemical calculations guiding the preparation of novel polyhalogen anions which are challenging but instructive to study undermatrixisolation conditions and which are expected to build up noncovalent networks. There is a number of important questions regarding all these non-covalent interactions, such as how strong they are and what are the main contributions, how these change with the conformation, and how these are affected by crystal packing effects etc, and finally, how can this knowledge be used to design novel structures and applications. A primary goal is the preparation of such novel weakly bound systems under matrixisolation conditions which allows a rigorous time independent spectroscopic characterization of effectively isolated molecular systems (pseudo-gas-phase conditions) at very low temperatures (<20 K). The experimental results obtained from sufficiently simple but highly challenging systems such as [F5]-, [Cl5]-, and analogous interhalide counterparts such as [F(Cl2)2]-, [Cl(Br2)2]-, [F(Br2)2]- will develop our understanding of noncovalent interaction in these electron-rich systems and will be used to validate state-of-the-art quantum chemical calculations. Beside spectroscopy on effectively isolated molecular species we intend to prepare novel polyhalogene monoanions also in bulk quantities, such as [Cln]-; n=5,7,9 and new interhalogen monoanions like [F(Br2)2]- or [Cl(Br2)2]-. This subproject will elucidate the transition from isolated molecular species to bulk quantities in solution, and to extended networks in the solid state. The preparation of novel species will be guided by a variety of available spectroscopic techniques such as low-temperature IR, UV/VIS, and in situ Raman spectroscopy, as well as single crystal x-ray structure determination, and their potential applications will be explored in combination with high-level quantum chemical studies.