Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, 35392, Giessen, Germany.
Center of Material Research (LaMa/ZfM), Justus Liebig University, Heinrich-Buff-Ring 16, 35392, Giessen, Germany.
Chemistry. 2022 Jul 6;28(38):e202200972. doi: 10.1002/chem.202200972. Epub 2022 Jun 3.
Herein, we report a series of azobenzene-substituted triptycenes. In their design, these switching units were placed in close proximity, but electronically separated by a sp center. The azobenzene switches were prepared by Baeyer-Mills coupling as key step. The isomerization behavior was investigated by H NMR spectroscopy, UV/Vis spectroscopy, and HPLC. It was shown that all azobenzene moieties are efficiently switchable. Despite the geometric decoupling of the chromophores, computational studies revealed excitonic coupling effects between the individual azobenzene units depending on the connectivity pattern due to the different transition dipole moments of the π→π* excitations. Transition probabilities for those excitations are slightly altered, which is also revealed in their absorption spectra. These insights provide new design parameters for combining multiple photoswitches in one molecule, which have high potential as energy or information storage systems, or, among others, in molecular machines and supramolecular chemistry.
本文报道了一系列取代的三联苯。在设计中，这些开关单元被放置得很近，但通过 sp 中心在电子上分离。作为关键步骤，通过 Baeyer-Mills 偶联制备了偶氮苯开关。通过 1 H NMR 光谱、UV/Vis 光谱和 HPLC 研究了其互变异构行为。结果表明，所有的偶氮苯部分都可以有效地进行开关操作。尽管发色团的几何解耦，但由于不同的π→π*激发跃迁偶极矩，计算研究表明，由于连接模式的不同，各个偶氮苯单元之间存在激子耦合效应。这些激发的跃迁概率略有改变，这也反映在它们的吸收光谱中。这些见解为在一个分子中组合多个光开关提供了新的设计参数，它们在能量或信息存储系统中具有很高的应用潜力，或者在分子机器和超分子化学等领域也具有很高的应用潜力。
