大连理工大学段春迎小组报道了，在辅助因子修饰的配位胶囊中保留电子，用于仿生电合成α-羟基/氨基酯。2024年9月24日出版的《美国化学会杂志》发表了这项成果。

据介绍，利用受氧化还原生物系统启发的人工催化剂，实现可持续的电化学转化，对催化合成具有重要意义。

在该研究中，团队开发了一种由含烟酰胺腺嘌呤二核苷酸(NADH)模拟物的，配位胶囊介导的仿生电合成策略，以有效地产生α-羟基/氨基酯。配位饱和金属中心充当电子继电器，连续接受单个电子，同时向NAD+模拟体提供两个电子。

在有或没有天然酶存在的情况下，中间体的质子化产生活性NADH模拟物，通过传统的酶流形对底物进行仿生氢化。胶囊的口袋封装了底物，并加强了底物和NADH模拟物之间的紧密距离，形成了一个预先组织的中间体，将氧化还原电位阳极移动0.4 V。

钴胶囊在一定电位范围内产生扁桃酸甲酯，与汉茨酯或天然NADH相比，在-1.2 V下操作时，收率提高到了92%。动力学实验显示Michaelis-Menten机制的Km为7.5 mM, Kcat为1.1 × 10^-2 s^-1。

该扩展策略与酶串联显示TON为650 mol^-1，初始TOF为185 mol^-1·h^-1，优于相关的Rh介导的酶电合成系统，为先进的人工电合成提供了一条有吸引力的途径。

附：英文原文

Title: Reserving Electrons in Cofactor Decorated Coordination Capsules for Biomimetic Electrosynthesis of α-Hydroxy/amino Esters

Author: Huali Wang, Yu Zhang, Guanfeng Ji, Jianwei Wei, Liang Zhao, Cheng He, Chunying Duan

Issue&Volume: September 24, 2024

Abstract: Sustainable electricity-to-chemical conversion via the utilization of artificial catalysts inspired by redox biological systems holds great significance for catalyzing synthesis. Herein, we develop a biomimetic electrosynthesis strategy mediated by a nicotinamide adenine dinucleotide (NADH) mimic-containing coordination capsule for efficiently producing α-hydroxy/amino esters. The coordination saturated metal centers worked as an electron relay to consecutively accept single electrons while donating two electrons to the NAD+ mimics simultaneously. The protonation of the intermediate generated  active NADH mimics for biomimetic hydrogenation of the substrates via the conventional enzymatic manifold with or without the presence of natural enzymes. The pocket of the capsule encapsulated the substrate and enforced the close proximity between the substrate and the NADH mimics, forming a preorganized intermediate to shift the redox potential by 0.4 V anodically. The cobalt capsule gave methyl mandelate over a range of applied potentials, with an improved yield of 92% when operated at 1.2 V compared to that of Hantzsch ester or natural NADH. Kinetic experiments revealed a Michaelis–Menten mechanism with a Km of 7.5 mM and a Kcat of 1.1 × 10–2 s–1. This extended strategy in tandem with an enzyme exhibited a TON of 650 molE–1 with an initial TOF of 185 molE–1·h–1, outperforming relevant Rh-mediated enzymatic electrosynthesis systems and providing an attractive avenue toward advanced artificial electrosynthesis.

DOI: 10.1021/jacs.4c08547

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c08547