Triplet excited-state organic chromophores present countless opportunities for applications in photocatalysis. Here we describe an approach to the engineering of the triplet excited states of aromatic chromophores, which involves incorporating pyrene into pyridinium-containing mechanically interlocked molecules (MIMs). The π-extended nature of the pyrenes enforces [π···π] stacking, affording an efficient synthesis of tetrachromophoric octacationic homo[2]catenanes. These MIMs generate triplet populations and efficient intersystem crossing on account of the formation of a mixed charge-transfer/exciplex electronic state and a nanoconfinement effect, which leads to a high level of protection of the triplet state and extends the triplet lifetimes and yields. These compounds display excellent catalytic activity in photo-oxidation, as demonstrated by the aerobic oxidation of a sulfur-mustard simulant. This research highlights the benefits of using the mechanical bond to fine-tune the triplet photophysics of existing aromatic chromophores, providing an avenue for the development of unexplored MIM-based photosensitizers and photocatalysts.

三重激发态有机发色团为光催化应用提供了无数机会。在这里，我们描述了一种设计芳香生色团三重激发态的方法，该方法涉及将芘掺入含吡啶鎓的机械互锁分子 (MIM) 中。芘的π扩展性质强制执行 [ π ··· π] 堆叠，提供了四发色八阳离子高 [2] 链烷的有效合成。由于混合的电荷转移/激子电子态的形成和纳米限制效应，这些 MIM 产生了三重态群体和有效的系统间交叉，这导致了对三重态的高水平保护并延长了三重态寿命和产量。这些化合物在光氧化中表现出优异的催化活性，硫芥模拟物的有氧氧化证明了这一点。这项研究强调了使用机械键来微调现有芳香生色团的三重态光物理的好处，为开发未开发的基于 MIM 的光敏剂和光催化剂提供了途径。