近日，香港大学何健团队实现了利用光激发Hantzsch酯制备高还原性非均相镍光催化剂。该项研究成果发表在2025年9月1日出版的《美国化学会志》上。

虽然人们已经实现了复杂的设计，将贵金属配合物和复杂的有机分子转化为活性光催化剂，用于单电子还原非活化的烷基卤化物，但基于地球丰富金属的高还原性光催化系统的发展仍处于早期阶段。

研究组证明了一个简单的三吡啶连接的镍（II）配合物，整合到一个亚胺连接的共价有机框架中，可以很容易地被光激发至Hantzsch酯还原，以产生具有相当低的激发态氧化电位的异相镍(I)光催化剂，大约为- 3.5 V（参照饱和甘汞电极）。框架支架内有效的电子转移过程和稳定镍(I)物种的约束效应有助于提高这种创新的异相镍光催化的性能。

值得注意的是，目前的系统允许大量减少催化剂负载，并在促进具有挑战性的有机卤化物亲电试剂和烯丙基砜之间的还原偶联方面表现出高可回收性。该研究表明，采用基于框架的多相化策略可以促进开发新型的具有地球丰富金属的机器人光氧化还原催化剂，用于可持续和实用的有机合成。

附：英文原文

Title: Developing a Highly Reducing Heterogeneous Nickel Photocatalyst with Photoexcited Hantzsch Esters

Author: Ming Cui, Deyang Wang, Jun Guo, Minhui Dai, Meng-Ying Sun, Zekun Li, Ching Kit Tommy Wun, Stephanie Bachmann, Wing Ying Chow, Tsz Woon Benedict Lo, Meng Zhou, Wen Wu Xu, Jian He

Issue&Volume: September 1, 2025

Abstract: While intricate designs have been implemented to transform noble-metal complexes and sophisticated organic molecules into reactive photocatalysts for the single-electron reduction of unactivated alkyl halides, the development of highly reducing photocatalytic systems based on earth-abundant metals is still in its early stages. Herein, we show that a simple terpyridine-ligated nickel(II) complex, integrated into an imine-linked covalent organic framework, can be readily reduced by photoexcited Hantzsch esters to produce a heterogeneous nickel(I) photocatalyst with a fairly low excited-state oxidation potential of approximately 3.5 V (referenced to the saturated calomel electrode). The efficient electron transfer processes within the framework support and the confinement effects that stabilize the nickel(I) species contribute to the improved performance of this innovative heterogeneous nickel photocatalysis in comparison to its homogeneous counterparts. Notably, the current system allows for substantial reductions in catalyst loadings and exhibits high recyclability in promoting reductive couplings between challenging organohalide electrophiles and allyl sulfones. Our research indicates that employing framework-based heterogenization strategies can facilitate the development of new classes of robust photoredox catalysts with earth-abundant metals for sustainable and practical organic synthesis.

DOI: 10.1021/jacs.5c10198

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.5c10198