Merging Nanoparticle and Capsule Single Electron Transfer Catalysis

自然界在生物合成中经常使用自由基过程。虽然各种辅因子被用来启动单电子转移（SET），但蛋白质框架发挥着与传统离子酶机制完全不同的作用-控制固有的反应性物质，而不是激活正常稳定的实体。最近，卢斯比小组发现了一种新的主客体化学方法，其中固有极化的Pd 2L 4笼状结构使用多个弱氢键封装客体。我们还发现，结合“激活”弱氧化性醌，如四氯对苯醌，使它们催化各种基于SET的反应（[4+2]，[2+2]环加成等）。未观察到未结合的醌。该项目提出了几个挑战和机遇。金属纳米颗粒以前没有被配位组装功能化，因此控制多主题配体的表面覆盖率等问题可能是成功的关键。然而，Kay开发的表面改性方法将促进这一雄心勃勃的探索性科学。4我们还预计，胶囊微环境可以调节以影响正向和反向SET，从而影响反应性，同时限制也将在控制区域和/或糖化选择性方面发挥关键作用。

Nature frequently uses radical processes in biosynthesis. While various co-factors are employed to initiate single electron transfer (SET), the protein framework plays a quite different role to conventional ionic enzyme mechanisms - controlling inherently reactive species rather than activating normally stable entities. Recently, the Lusby group uncovered a novel approach to host-guest chemistry wherein an inherently polarised Pd2L4 cage structure encapsulates guests using multiple weak H-bonds. We have also found that binding "activates" weakly-oxidising quinones, such as chloranil, so that they catalyse various SET-based reactions ([4+2], [2+2] cycloadditions etc.) not observed for the unbound quinones.This project presents several challenges and opportunities. Metal nanoparticles have not previously been functionalised with coordination assemblies, therefore issues such as controlling surface coverage of multitopic ligands will likely be key to success. However, the surface modification methodology developed by Kay will facilitate this ambitious exploratory science.4 We also anticipate that the capsule microenvironment can be tuned to affect both forward and reverse SET and hence reactivity, while the confines will also play a key role in controlling regio and/or diastreoselectivity.