Abstract:
We report a sensitive method for comparing weak interactions between aryl rings located on the external surfaces of equilibrating homo- and heterodimeric capsules. Two identical self-complementary resorcin[4]arene tetrabenzoate molecules and one tetramethylammonium cation form in CDCl3 hydrogen-bonded homodimeric capsules whose exteriors are decorated with four tight pairs of weakly interacting aryl rings. The pair wise mixing of six different homodimers establishes their equilibria with the corresponding heterodimeric species in which two types of aryl rings exert on each other some gentle forces. This equilibrium is significantly shifted either towards homo- or heterodimers depending on the nature and location of the substituents in the weakly interacting aryl rings. The thermodynamic favorability or disadvantage of the heterodimerization is determined by stronger or weaker aryl-aryl attractions in the hetero- or homodimeric capsules, respectively. The four-fold amplification of weak aryl-aryl interactions on the external surfaces of the equilibrating capsules is responsible for high sensitiveness of our approach.
摘要:
我们报告了一种灵敏的方法,用于比较位于平衡的均聚和异二聚体胶囊外表面上的芳基环之间的弱相互作用。两个相同的自互补间苯二酚[4]芳烃四苯甲酸酯分子和一个四甲基铵阳离子在CDCl3氢键键合的同二聚体胶囊中形成,其外部装饰有四对紧密的弱相互作用的芳基环。六个不同的同二聚体的成对混合建立了它们与相应的异二聚体物种的平衡,其中两种类型的芳基环彼此施加一些温和的力。取决于弱相互作用的芳基环中取代基的性质和位置,该平衡向均二聚体或杂二聚体显著移动。异二聚化的热力学有利性或不利性由异或同二聚体胶囊中更强或更弱的芳基-芳基吸引力决定,分别。平衡胶囊外表面上的弱芳基-芳基相互作用的四倍放大是我们方法的高灵敏度的原因。