Two-State Reactivity in Low-Valent Iron-Mediated C-H Activation and the Implications for Other First-Row Transition Metals

	Two-State Reactivity in Low-Valent Iron-Mediated C-H Activation and the Implications for Other First-Row Transition Metals
	Sun, Yihua 1; Tang, Hao 1; Chen, Kejuan 1; Hu, Lianrui 1; Yao, Jiannian 1; Shaik, Sason 2,3; Chen, Hui 1
刊名	JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
	2016-03-23
卷号	138 期号:11 页码:3715-3730
英文摘要	C-H bond activation/functionalization promoted by low-valent iron complexes has recently emerged as a promising approach for the utilization of earth-abundant first row transition metals to carry out this difficult transformation. Herein we use extensive density functional theory and high-level ab initio coupled cluster calculations to shed light on the mechanism of these intriguing reactions. Our key mechanistic discovery for C-H atylation reactions reveals a two-state reactivity (TSR) scenario in which the low-spin Fe(II) singlet state, which is initially an excited state, crosses over the high-spin ground state and promotes C-H bond cleavage. Subsequently, aryl transmetalation occurs, followed by oxidation of Fe(II) to Fe(III) in a single-electron transfer (SET) step in which dichloroalkane serves as an oxidant, thus promoting the final C-C coupling and finalizing the C-H functionalization. Regeneration of the Fe(II) catalyst for the next round of C-H activation involves SET oxidation of the Fe(I) species generated after the C-C bond coupling. The ligand sphere of iron is found to play a crucial role in the TSR mechanism by stabilization of the reactive low-spin state that mediates the C-H activation. This is the first time that the successful TSR concept conceived for high-valent iron chemistry is shown to successfully rationalize the reactivity for a reaction promoted by low-valent iron complexes. A comparative study involving other divalent middle and late first-row transition metals implicates iron as the optimum metal in this TSR mechanism for C-H activation. It is predicted that stabilization of low-spin Mn(II) using an appropriate ligand sphere should produce another promising candidate for efficient C-H bond activation. This new TSR scenario therefore emerges as a new strategy for using low-valent first-row transition metals for C-H activation reactions.
收录类别	SCI
语种	英语
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/35960]
专题	化学研究所_光化学实验室
作者单位	1.Chinese Acad Sci, Inst Chem, Key Lab Photochem, BNLMS, Beijing 100190, Peoples R China 2.Hebrew Univ Jerusalem, Inst Chem, IL-91904 Jerusalem, Israel 3.Hebrew Univ Jerusalem, Lise Meitner Minerva Ctr Computat Quantum Chem, IL-91904 Jerusalem, Israel
推荐引用方式 GB/T 7714	Sun, Yihua,Tang, Hao,Chen, Kejuan,et al. Two-State Reactivity in Low-Valent Iron-Mediated C-H Activation and the Implications for Other First-Row Transition Metals[J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY,2016,138(11):3715-3730.
APA	Sun, Yihua.,Tang, Hao.,Chen, Kejuan.,Hu, Lianrui.,Yao, Jiannian.,...&Chen, Hui.(2016).Two-State Reactivity in Low-Valent Iron-Mediated C-H Activation and the Implications for Other First-Row Transition Metals.JOURNAL OF THE AMERICAN CHEMICAL SOCIETY,138(11),3715-3730.
MLA	Sun, Yihua,et al."Two-State Reactivity in Low-Valent Iron-Mediated C-H Activation and the Implications for Other First-Row Transition Metals".JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 138.11(2016):3715-3730.