德国开姆尼茨工业大学Teichert Johannes F.团队报道了光开关中性同芳烃。相关研究成果发表在2023年1月26日出版的《自然—化学》。

同芳香族化合物具有中断的π系统，但由于通过空间或通过键相互作用而显示出芳香性质。稳定的中性均芳香烃仍然很少，且通常不稳定。

该文中，研究人员介绍了一类稳定的中性同芳香分子的制备，并得到实验证据（通过NMR光谱观察到的环电流和通过X射线结构分析实现的键长均衡）和通过非核化学位移（NICS）和诱导电流密度各向异性（ACID）进行的计算分析提供的验证。研究还表明，同芳香烃是一种通过可逆光化学[1，11]顺向重排的光开关。

计算分析表明，在光开关时，同芳香态的性质在其周边从更明显的局部6π同芳香态变化到全局10π同芳香状态。这些稳定和易制备的均芳香族中性烃及其光开关行为的演示为研究有机分子中的同共轭相互作用以及设计新的响应分子材料提供了新的理解和见解。

附：英文原文

Title: Photoswitching neutral homoaromatic hydrocarbons

Author: Tran Ngoc, Trung, Grabicki, Niklas, Irran, Elisabeth, Dumele, Oliver, Teichert, Johannes F.

Issue&Volume: 2023-01-26

Abstract: Homoaromatic compounds possess an interrupted π system but display aromatic properties due to through-space or through-bond interactions. Stable neutral homoaromatic hydrocarbons have remained rare and are typically unstable. Here we present the preparation of a class of stable neutral homoaromatic molecules, supported by experimental evidence (ring current observed by NMR spectroscopy and equalization of bond lengths by X-ray structure analysis) and computational analysis via nucleus-independent chemical shifts (NICS) and anisotropy of the induced current density (ACID). We also show that one homoaromatic hydrocarbon is a photoswitch through a reversible photochemical [1,11] sigmatropic rearrangement. Our computational analysis suggests that, upon photoswitching, the nature of the homoaromatic state changes in its perimeter from a more pronounced local 6π homoaromatic state to a global 10π homoaromatic state. These demonstrations of stable and accessible homoaromatic neutral hydrocarbons and their photoswitching behaviour provide new understanding and insights into the study of homoconjugative interactions in organic molecules, and for the design of new responsive molecular materials.

DOI: 10.1038/s41557-022-01121-w

Source: https://www.nature.com/articles/s41557-022-01121-w