Photocatalytic C–H activation and the subtle role of chlorine radical complexation in reactivity

doi:10.1126/science.abd8408

GSTDTAP > 气候变化

DOI	10.1126/science.abd8408
	Photocatalytic C–H activation and the subtle role of chlorine radical complexation in reactivity
	Qiaomu Yang; Yu-Heng Wang; Yusen Qiao; Michael Gau; Patrick J. Carroll; Patrick J. Walsh; Eric J. Schelter
	2021-05-21
发表期刊	Science
出版年	2021
英文摘要	Radicals are atoms or molecules that are highly reactive because they have an unpaired electron. A common means of investigating whether they are involved in a particular reaction is to try to trap them with an acceptor compound. Yang et al. reinvestigated a photoinduced alkane oxidation reaction for which a trapping study had previously implicated alkoxy radicals. Their spectroscopic, kinetic, and isotopic labeling studies revealed that chlorine, rather than alkoxy, was the key radical intermediate; the prior trapping results had stemmed from its complexation with alcohols. Science , abd8408, this issue p. [847][1] The functionalization of methane, ethane, and other alkanes derived from fossil fuels is a central goal in the chemical enterprise. Recently, a photocatalytic system comprising [CeIVCl5(OR)]2− [CeIV, cerium(IV); OR, –OCH3 or –OCCl2CH3] was disclosed. The system was reportedly capable of alkane activation by alkoxy radicals (RO•) formed by CeIV–OR bond photolysis. In this work, we present evidence that the reported carbon-hydrogen (C–H) activation of alkanes is instead mediated by the photocatalyst [NEt4]2[CeCl6] (NEt4+, tetraethylammonium), and RO• are not intermediates. Spectroscopic analyses and kinetics were investigated for C–H activation to identify chlorine radical (Cl•) generation as the rate-limiting step. Density functional theory calculations support the formation of \[Cl•\]\[alcohol\] adducts when alcohols are present, which can manifest a masked RO• character. This result serves as an important cautionary note for interpretation of radical trapping experiments. [1]: /lookup/doi/10.1126/science.abd8408
领域	气候变化 ; 资源环境
URL	查看原文
引用统计
文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/328829
专题	气候变化资源环境科学
推荐引用方式 GB/T 7714	Qiaomu Yang,Yu-Heng Wang,Yusen Qiao,等. Photocatalytic C–H activation and the subtle role of chlorine radical complexation in reactivity[J]. Science,2021.
APA	Qiaomu Yang.,Yu-Heng Wang.,Yusen Qiao.,Michael Gau.,Patrick J. Carroll.,...&Eric J. Schelter.(2021).Photocatalytic C–H activation and the subtle role of chlorine radical complexation in reactivity.Science.
MLA	Qiaomu Yang,et al."Photocatalytic C–H activation and the subtle role of chlorine radical complexation in reactivity".Science (2021).