Nature publishes study on irreversible metal-to-ligand charge transfer in copper complexes

Study details

A study titled "Carbon radical generation by irreversible metal-to-ligand charge transfer" was published in Nature on 04 November 2026. The authors are Zhiqiang Wei, Xiang Li, Lin Xiao, Yu He, Zhao Liu, Kaidi Zhu, Chuanfa Ni, Xiao-Song Xue and Jinbo Hu. The article is citable and carries a permanent DOI: It was received on 14 April 2026 and accepted on 28 October 2026. The version shared is subject to further edits and will be replaced automatically by the final Version of Record.

Research findings

The study reports a class of isolable copper–heteroaryl sulfone complexes that, upon visible light irradiation, undergo an irreversible MLCT-driven fragmentation through C–S bond cleavage within the coordinated sulfone ligand, generating carbon-centered radicals. Spectroscopic and computational studies support the formation of MLCT-derived excited states and a low-barrier pathway for C–S bond cleavage.

The reactivity is largely independent of the reduction potentials of the corresponding free sulfones, enabling the generation of fluoroalkyl and non-fluorinated tertiary, secondary, and primary (even methyl) alkyl radicals.

The researchers demonstrate the utility of this platform in copper-catalyzed C–H fluoroalkylation of arenes and terminal alkynes. Leveraging these MLCT-generated trifluoromethyl radicals to initiate halogen-atom transfer (XAT) from perfluorocyclobutyl iodide (I-FCB), they also achieve radical perfluorocyclobutylation–iodination of alkenes, addressing a longstanding challenge in the incorporation of perfluorocyclobutyl motifs.

Background and authors

Metal-to-ligand charge transfer (MLCT) is described in the study as a fundamental photoinduced process that underpins a broad range of energy- or electron-transfer events. In the absence of productive substrate engagement, the MLCT excited state typically relaxes to the ground state via photophysical deactivation, reflecting its largely reversible character.

The authors are affiliated with the State Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China, and the School of Physical Science and Technology, ShanghaiTech University, Shanghai, China. Zhiqiang Wei, Xiang Li, Lin Xiao and Yu He contributed equally. Correspondence is to Xiao-Song Xue or Jinbo Hu.

Why it matters

The study presents a method for generating carbon-centered radicals through irreversible MLCT-driven fragmentation, which the researchers say enables radical formation that is largely independent of the reduction potentials of free sulfones. The platform is demonstrated in copper-catalyzed C–H fluoroalkylation of arenes and terminal alkynes, and in radical perfluorocyclobutylation–iodination of alkenes, which the study describes as addressing a longstanding challenge in the incorporation of perfluorocyclobutyl motifs.

Sources

• nature.com: Carbon radical generation by irreversible metal-to-ligand charge transfer | Nature

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