Nie Shi-Xin, Huang Teng-Yu, Guo Hao, Wang Li-Xia, Cui Jie, Xiang Jun-Feng, Ao Yu-Fei, Wang De-Xian, Wang Qi-Qiang
Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
J Am Chem Soc. 2022 Dec 21;144(50):22884-22889. doi: 10.1021/jacs.2c12202. Epub 2022 Dec 8.
Xenon binding represents a formidable challenge, and efficient hosts remain rare. Here we report our findings that while enantiomeric bis(urea)-bis(thiourea) macrocycles form exclusive homochiral dimeric assemblies, xenon is able to overcome the narcissism and induces an otherwise-nonobservable heterochiral assembly as its preferred host. An experimental approach and fitting model were developed to obtain binding constants associated with the invisible assembly species. The determined xenon binding affinity with the heterochiral capsule reaches 1600 M, which is 15 times higher than that with the homochiral capsule and represents the highest record for an assembled host. The origin of the large difference in xenon affinity between the two subtle diastereotopic assemblies was revealed by single-crystal analysis. In the heterochiral capsule with symmetry, the xenon atom is more tightly enclosed by van der Waals surroundings of the four thiourea groups arranged in a spherical cross-array, superior to the antiparallel array in the homochiral capsule with symmetry.
氙气结合是一项艰巨的挑战，高效的主体仍然很少见。在此，我们报告我们的研究发现，虽然对映体双（脲）-双（硫脲）大环形成排他性的同手性二聚体组装体，但氙气能够克服这种“自恋”现象，并诱导出一种原本不可观察到的异手性组装体作为其优选主体。我们开发了一种实验方法和拟合模型来获得与不可见组装物种相关的结合常数。测定的氙气与异手性胶囊的结合亲和力达到1600 M，这比与同手性胶囊的结合亲和力高15倍，代表了组装主体的最高记录。通过单晶分析揭示了这两种微妙的非对映异位组装体之间氙气亲和力存在巨大差异的原因。在具有 对称性的异手性胶囊中，氙原子被以球形交叉阵列排列的四个硫脲基团的范德华环境更紧密地包围，优于具有 对称性的同手性胶囊中的反平行阵列。
