Zheng Jieyu, Yang Yuchong, Ronson Tanya K, Wood Daniel M, Nitschke Jonathan R
Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
Adv Mater. 2023 Oct;35(42):e2302580. doi: 10.1002/adma.202302580. Epub 2023 Sep 19.
Precise control over guest release and recapture using external stimuli is a valuable goal, potentially enabling new modes of chemical purification. Including redox moieties within the ligand cores of molecular capsules to trigger the release and uptake of guests has proved effective, but this technique is limited to certain capsules and guests. Herein, the construction of a series of novel metal-organic capsules from ditopic, tritopic, and tetratopic ligands is demonstrated, all of which contain redox-active azo groups coordinated to Fe centers. Compared to their iminopyridine-based analogs, this new class of azopyridine-based capsules possesses larger cavities, capable of encapsulating more voluminous guests. Upon reduction of the capsules, their guests are released and may then be re-encapsulated when the capsules are regenerated by oxidation. Since the redox centers are on the ligand arms, they are modular and can be attached to a variety of ligand cores to afford varying and predictable architectures. This method thus shows promise as a generalized approach for designing redox-controlled guest release and uptake systems.
利用外部刺激精确控制客体的释放和再捕获是一个有价值的目标，这有可能实现新的化学纯化模式。在分子胶囊的配体核心中引入氧化还原部分以触发客体的释放和摄取已被证明是有效的，但该技术仅限于某些胶囊和客体。在此，展示了由双齿、三齿和四齿配体构建一系列新型金属有机胶囊，所有这些胶囊都含有与铁中心配位的氧化还原活性偶氮基团。与基于亚氨基吡啶的类似物相比，这类新型基于偶氮吡啶的胶囊具有更大的空腔，能够封装体积更大的客体。当胶囊被还原时，其客体被释放，然后当胶囊通过氧化再生时，客体可以被重新封装。由于氧化还原中心位于配体臂上，它们具有模块化特点，可以连接到各种配体核心上，以提供不同且可预测的结构。因此，这种方法有望成为设计氧化还原控制的客体释放和摄取系统的通用方法。
