Investigation of London Dispersion Interactions with Azobenzene Switches

大群的影响主要是根据它们的排斥相互作用来考虑的。最近，人们认识到范德华相互作用的吸引部分，即伦敦色散，可以用作分子和反应设计中的稳定元素。尽管取得了进展，但这些力量的性质仍然没有得到充分了解。特别是对不同基团（分散供体基团= ddg）的分散强度的实验评价几乎没有得到解决。一个长期争论的问题是溶剂化对分散的影响。在过去的几年里，我们可以证明偶氮苯从Z-到e -异构体的热反反应是解决这些问题的理想方法。它允许两个ddg近距离定位。通过检测异构化速率，可以根据Bell-Evans-Polyani关系来评价各种ddg的稳定性。本文将根据其分散强度对从烷基到与生命科学相关的结构，如肽、核碱基等各种ddg进行比较。此外，还将研究不同溶剂对给定ddg分散强度的影响，为如何设计理想的条件以最佳地利用分散相互作用提供必要的指导。这些研究将与spp1807催化、超分子化学和结构分析领域的其他小组合作完成。

The effect of bulky groups has been mainly considered according to their repulsive interactions. Recently, it has been realized, that the attractive part of the van-der-Waals interactions, London dispersion, can be utilized as stabilizing element in molecular and reaction design. Despite the progress made, the nature of these forces are still not fully understood. Especially the experimental evaluation of the strength in terms of dispersion of different groups (dispersion donor groups = DDGs) has only been scarcely addressed. A long disputed issue is the effect of solvation on dispersion. In the past years, we could show that the thermal back reaction of azobenzene from the Z- to the E-isomer is ideally suited to address these questions. It allows positioning two DDGs in close proximity. By examining the isomerization rate, the stability of various DDGs can be assayed based on the Bell-Evans-Polyani relationship. Herein, various DDGs ranging from alkyl to structures relevant in life science, such as peptides, nucleobases, etc. will compared according to their dispersion strength. Furthermore, the influence of different solvents on the dispersion strength of given DDGs will be investigated providing essential guidelines, how to design ideal conditions to make the best use of dispersive interactions. The studies will be completed with collaborative efforts with other groups within the SPP 1807 in the area of catalysis, supramolecular chemistry and structural analysis.