Oberhof Nils, Darian Leon Kambiz Paschai, Dreuw Andreas
Interdisciplinary Center for Scientific Computing, Heidelberg University, Im Neuenheimer Feld 205, 69120, Heidelberg, Germany.
Chemphyschem. 2025 Feb 16;26(4):e202400799. doi: 10.1002/cphc.202400799. Epub 2024 Nov 29.
Systems with multiple photoswitchable units in one molecule have attracted considerable attention in the past years as they are useful for a broad variety of possible applications. Especially, linked azobenzenes sharing one benzene ring are of high interest since their direct linkage introduces an additional photoswitchable unit at only small increase in molecular weight. In this spirit, linear oligo-azobenzenes had been synthesized, though their photochemical properties have only been investigated for short chain lengths. In this study, we use (time-dependent) density functional methodology for the evaluation of the excitations of meta- and para-connected oligo-azobenzenes to predict their switching ability. It becomes apparent, that the meta connection pattern enables each azobenzene subunit to act as an individual switchable unit, whereas they are strongly coupled and loose their individuality in para connection. Therefore, meta-oligo-azobenzenes are ideal candidates for future studies of azobenzene-based functional polymers, while para-oligo-azobenzenes are not.
在过去几年中，一个分子中具有多个光开关单元的体系因其在广泛的可能应用中有用而备受关注。特别是，共享一个苯环的连接偶氮苯备受关注，因为它们的直接连接仅在分子量略有增加的情况下就引入了一个额外的光开关单元。本着这种精神，线性低聚偶氮苯已被合成，尽管它们的光化学性质仅针对短链长度进行了研究。在本研究中，我们使用（含时）密度泛函方法来评估间位和对位连接的低聚偶氮苯的激发，以预测它们的开关能力。很明显，间位连接模式使每个偶氮苯亚基能够作为一个独立的可开关单元起作用，而在对位连接中它们强烈耦合并失去其个体性。因此，间位低聚偶氮苯是未来基于偶氮苯的功能聚合物研究的理想候选物，而对位低聚偶氮苯则不是。
