美国哈佛大学Daniel G. Nocera团队报道了Ag(II)全氟烷基羧酸盐LMCT激发的光电催化全氟烷基化。相关研究成果于2023年12月14日发表在国际顶尖学术期刊《科学》。

分子Ag（II）配合物是一种超氧化性光氧化还原催化剂，能够从氧化还原抑制剂底物中产生自由基。

该本文中，研究人员通过可见光诱导均解激活三氟乙酸(TFA)，开发了[Ag(bpy)₂(TFA)][OTf]和Ag(bpy)(TFA)₂配合物中Ag(II)中心的亲电性。生成的三氟甲基自由基可与多种芳烃反应形成C(sp²) -CF₃键。该方法是通用的，并扩展到其他链长更高的全氟烷基羧酸盐（R_FCO₂^-；RF=CF₂CF₃或CF₂CF₂CF₃）。

光氧化还原反应可以通过在辐照期间电化学再生Ag（II）络合物而被赋予电子光催化作用。通过光激发Ag（II）–TFA配体到金属电荷转移（LMCT）态，然后将Ag（I）光产物电化学再氧化回Ag（Ⅱ）光反应剂，实现了周转数超过20的芳烃的电光催化全氟烷基化。

附：英文原文

Title: Electrophotocatalytic perfluoroalkylation by LMCT excitation of Ag(II) perfluoroalkyl carboxylates

Author: Brandon M. Campbell, Jesse B. Gordon, Elaine Reichert Raguram, Miguel I. Gonzalez, Kristopher G. Reynolds, Matthew Nava, Daniel G. Nocera

Issue&Volume: 2023-12-14

Abstract: Molecular Ag(II) complexes are super-oxidizing photoredox catalysts capable of generating radicals from redox reticent substrates. Herein, we exploit the electrophilicity of Ag(II) centers in [Ag(bpy)2(TFA)][OTf] and Ag(bpy)(TFA)2 complexes to activate trifluoroacetate (TFA) by visible-light-induced homolysis. The resulting trifluoromethyl radicals may react with a variety of arenes to forge C(sp2)–CF3 bonds. This methodology is general and extends to other perfluoroalkyl carboxylates of higher chain length (RFCO2–; RF = CF2CF3 or CF2CF2CF3). The photoredox reaction may be rendered electrophotocatalytic by regenerating the Ag(II) complexes electrochemically during irradiation. Electrophotocatalytic perfluoroalkylation of arenes at turnover numbers exceeding 20 is accomplished by photoexciting the Ag(II)–TFA ligand-to-metal charge transfer (LMCT) state followed by electrochemical re-oxidation of the Ag(I) photoproduct back to the Ag(II) photoreactant.

DOI: adk4919

Source: https://www.science.org/doi/10.1126/science.adk4919