High-affinity guests have been reported for the macrocyclic host cucurbit[7]uril (CB[7]), enabling widespread applications, but hindering CB[7] materials from being returned to their guest-free state for reuse. Here, we present polyhedral boron clusters (carboranes) as strongly binding, yet easily removable, guests for CB[7]. Aided by a Pd-catalyzed coupling of an azide anion, we prepared boron-functionalized 9-amino-ortho-carborane that binds to CB[7] with a Ka ≈ 1010 M-1. Upon basic treatment, ortho-carborane readily undergoes deboronation to yield anionic nido-carborane, a poor guest for CB[7], facilitating recovery of guest-free CB[7]. We showcase the utility of the modified ortho-carborane guest by recycling a CB[7]-functionalized resin. With this report, we introduce stimuli-responsive decomplexation as an additional consideration in the design of high-affinity host-guest complexes.

中文翻译：

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用于 Cucurbit[7]uril 的碳硼烷客体促进强结合和按需去除

据报道，大环宿主葫芦[7]脲（CB[7]）具有高亲和力，可实现广泛应用，但阻碍了CB[7]材料恢复到无客体状态以供重复使用。在这里，我们提出多面体硼簇（碳硼烷）作为 CB [7] 的强结合且易于去除的客体。在 Pd 催化的叠氮阴离子偶联的帮助下，我们制备了硼功能化的 9-氨基邻碳硼烷，它以 Ka ≈ 1010 M-1 与 CB[7] 结合。在碱性处理后，邻碳硼烷很容易发生脱硼反应，生成阴离子基碳硼烷，它是 CB 的不良客体 [7]，促进了无客体 CB [7] 的回收。我们通过回收 CB[7]-官能化树脂来展示改性邻碳硼烷客体的效用。有了这份报告，