State Key Laboratory of Fine Chemicals, Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian, 116024, China.
Angew Chem Int Ed Engl. 2022 Jan 10;61(2):e202114490. doi: 10.1002/anie.202114490. Epub 2021 Nov 22.
The activation and oxidization of inert C(sp )-H bonds into value-added chemicals affords attractively economic and ecological benefits as well as central challenge in modern chemistry. Inspired by the natural enzymatic transformation, herein, we report a new multiphoton excitation approach to activate the inert C(sp )-H bonds and oxygen by integrating the photoinduced electron transfer (PET), ligand-to-metal charge transfer (LMCT) and hydrogen atom transfer (HAT) events together into one metal-organic framework. The well-modified nicotinamide adenine dinucleotide (NAD ) mimics oxidized Ce -OEt moieties to generate Ce -OEt chromophore and its reduced state mimics NAD via PET. The in situ formed Ce -OEt moiety triggers a LMCT excitation to form the alkoxy radical EtO , abstracts a hydrogen atom from the C(sp )-H bond, accompanying the recovery of Ce -OEt and the formation of alkyl radicals. The formed NAD activates oxygen to regenerate the NAD for next recycle, wherein, the activated oxygen species interacts with the intermediates for the oxidization functionalization, paving a catalytic avenue for developing scalable and sustainable synthetic strategy.
惰性 C(sp )-H 键的活化和氧化为增值化学品提供了极具吸引力的经济和生态效益，同时也是现代化学的核心挑战。受自然酶促转化的启发，本文报道了一种新的多光子激发方法，通过将光诱导电子转移（PET）、配体到金属电荷转移（LMCT）和氢原子转移（HAT）事件整合到一个金属-有机骨架中，来激活惰性 C(sp )-H 键和氧。经过精心修饰的烟酰胺腺嘌呤二核苷酸（NAD ）模拟氧化的 Ce -OEt 部分生成 Ce -OEt 生色团，其还原态通过 PET 模拟 NAD。原位形成的 Ce -OEt 部分触发 LMCT 激发，形成烷氧基自由基 EtO ，从 C(sp )-H 键中夺取一个氢原子，伴随着 Ce -OEt 的恢复和烷基自由基的形成。形成的 NAD 激活氧气以再生 NAD 用于下一次循环，其中，活化的氧物种与中间体相互作用，进行氧化官能化，为开发可扩展和可持续的合成策略铺平了催化途径。
