Hein Robert, Gisbert Yohan, Feringa Ben L
Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 3, Groningen 9747 AG, the Netherlands.
Organic Chemistry Institute, University of Münster, Corrensstraße 40, Münster 48149, Germany.
J Am Chem Soc. 2025 Apr 23;147(16):13649-13657. doi: 10.1021/jacs.5c00997. Epub 2025 Apr 11.
The modulation of molecular recognition underpins numerous wide-ranging applications and has inspired the development of a myriad of switchable receptors, in particular photo- or redox-responsive hosts. Herein, we report a highly versatile three-state cation receptor family and switch system based on an overcrowded alkene strapped with crown ethers, which can be switched by both redox and light stimuli, thereby combining the advantages of both approaches. Specifically, the neutral switches can be quantitatively converted between and folded receptor geometries by irradiation, leading to the discovery of a significant increase or decrease in cation binding affinity, which was exploited to shuttle the pseudorotaxane-forming dibenzylammonium guest between the switchable crown ethers of slightly different sizes. Alternatively, two-electron oxidation to the orthogonal, dicationic, nonvolatile state completely turns off cation binding to the host, thereby ejecting the guest. Upon reduction, the metastable folded state is first formed, which then thermally relaxes, resulting in a unique, autonomous, and cation-dependent multistate switching cascade.
分子识别的调控是众多广泛应用的基础，并激发了无数可切换受体的发展，特别是光响应或氧化还原响应主体。在此，我们报道了一个基于冠醚修饰的过度拥挤烯烃的高度通用的三态阳离子受体家族和开关系统，它可以通过氧化还原和光刺激进行切换，从而结合了两种方法的优点。具体而言，中性开关可以通过光照在展开和折叠的受体几何结构之间进行定量转换，导致阳离子结合亲和力显著增加或降低，这被用于在尺寸略有不同的可切换冠醚之间穿梭形成准轮烷的二苄基铵客体。或者，将其氧化为正交的双阳离子非挥发性状态会完全关闭阳离子与主体的结合，从而排出客体。还原时，首先形成亚稳态折叠态，然后热弛豫，产生独特、自主且依赖阳离子的多态切换级联反应。
