Chalcogen Bonding and Hydrophobic Effects Force Molecules into Small Spaces
Chalcogen Bonding and Hydrophobic Effects Force Molecules into Small Spaces
复制标题
硫族键合和疏水效应迫使分子进入小空间
DOI：
10.1021/jacs.0c01290
复制
发表时间：
2020-03-25
影响因子：
15
通讯作者：
Yu, Yang
中科院分区：
文献类型：
--
作者：
Rahman, Faiz-Ur;Tzeli, Demeter;Yu, Yang
超分子胶囊是研究小空间分子行为的理想容器，并在运输、催化和材料科学领域提供应用。我们在这里报告了使用硫属元素键合来形成在水中稳定的容器组件。由间苯二酚[4]芳烃以良好的收率合成了用2,1,3-苯并硒二唑壁功能化的空穴配体1-3。 3的固态单晶X射线结构显示出通过多个Se中心点N硫族键粘合在一起的二聚体组装体。通过 H-1 NMR 方法研究了 D2O 中疏水性和两亲性客体的结合，并揭示了 1:1、2:1 和 2:2 化学计量的主客体组装。小客体（例如正己烷或环己烷）组装为 2:2 胶囊复合物，较大客体（例如环己烷羧酸或环癸烷）形成 1:1 空配体复合物，较长的线性客体（例如正十二烷、环己烷羧酸酐和酰胺）形成 2:1 胶囊复合物。胶囊与环己烷羧酸酐的2:1复合物稳定超过2周，表明硫族键接缝是“防水的”。用胶囊在水溶液中观察到环己烷相对于苯的选择性吸收和甲基环己烷相对于甲苯的选择性吸收。客体分子（例如 3-甲基丁酸）之间的疏水力和氢键吸引力在水的竞争作用下稳定了组装体。 Se 的高极化性和适度的电负性提供了与客体 C-H 键互补的胶囊内衬。 2,1,3苯并硒二唑壁赋予胶囊环境异常高的磁各向异性，这得到了密度泛函理论计算的支持。
Supramolecular capsules are desirable containers for the study of molecular behavior in small spaces and offer applications in transport, catalysis, and material science. We report here the use of chalcogen bonding to form container assemblies that are stable in water. Cavitands 1-3 functionalized with 2,1,3-benzoselenadiazole walls were synthesized in good yield from resorcin[4]arenes. The solid-state single-crystal X-ray structure of 3 showed a dimeric assembly cemented together through multiple Se center dot center dot center dot N chalcogen bonds. Binding of hydrophobic and amphiphilic guests in D2O was investigated by H-1 NMR methods and revealed host- guest assemblies of 1:1, 2:1, and 2:2 stoichiometries. Small guests such as n-hexane or cyclohexane assembled as 2:2 capsular complexes, larger guests like cyclohexane carboxylic acid or cyclodecane formed 1:1 cavitand complexes, and longer linear guests like ndodecane, cyclohexane carboxylic acid anhydride, and amides created 2:1 capsular complexes. The 2:1 complex of the capsule with cyclohexane carboxylic acid anhydride was stable over 2 weeks, showing that the seam of chalcogen bonds is "waterproof". Selective uptake of cyclohexane over benzene and methyl cyclohexane over toluene was observed in aqueous solution with the capsule. Hydrophobic forces and hydrogen-bonding attractions between guest molecules such as 3-methylbutanoic acid stabilized the assemblies in the presence of the competing effects of water. The high polarizability and modest electronegativity of Se provide a capsule lining complementary to guest C-H bonds. The 2,1,3benzoselenadiazole walls impart an unusually high magnetic anisotropy to the capsule environment, which is supported by density functional theory calculations.