Max-Born-Institut, Max-Born-Str. 2A, 12489 Berlin, Germany.
J Am Chem Soc. 2010 Feb 17;132(6):1831-8. doi: 10.1021/ja903636q.
Optical properties and the geometric structure of self-assembled monolayers of azobenzene-functionalized alkanethiols have been investigated by UV/visible and near edge X-ray absorption fine structure spectroscopy in combination with density-functional theory. By attaching a trifluoro-methyl end group to the chromophore both the molecular tilt and twist angle of the azobenzene moiety are accessible. Based on this detailed structural analysis the energetic shifts observed in optical reflection spectroscopy can be qualitatively described within an extended dipole model. This substantiates sizable excitonic coupling among the azobenzene chromophores as an important mechanism that hinders trans to cis isomerization in densely packed self-assembled monolayers.
通过紫外/可见和近边 X 射线吸收精细结构光谱学与密度泛函理论相结合，研究了偶氮苯功能化烷硫醇的自组装单层的光学性质和几何结构。通过在生色团上连接三氟甲基端基，可以获得偶氮苯部分的分子倾斜和扭转角。基于这种详细的结构分析，可以在扩展偶极子模型中定性描述在光学反射光谱中观察到的能量位移。这证实了在密集组装的自组装单层中，偶氮苯发色团之间存在相当大的激子耦合，这是阻碍反式到顺式异构化的重要机制。
