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Paired electrolysis enables selective C–N coupling for the synthesis of nitrogenous aromatics

Nature Synthesis (2026)Cite this article

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Abstract

Nitrogen-containing aromatic compounds, such as aromatic imines and aromatic oximes, are vital in the pharmaceutical and agrochemical industries. However, their synthesis via conventional C–N coupling strategies remains dependent on fossil-derived feedstocks and energy-intensive processes. Here we report a paired electrolysis integrating lignin cleavage with subsequent C–N coupling to synthesize these compounds. The system uses a Pd1/TivO2-NS cathode (palladium single atoms confined in titanium vacancies on monolayer TivO2 nanosheets) and a PbO2 plate anode in phosphate electrolyte. During electrolysis, lignin-derived polyols generated by cathodic cleavage are oxidized to carbonyl intermediates at the anode while nitroarenes are reduced to amines at the cathode, enabling C–N bond formation. Using poplar lignin and nitrobenzene, an aryl imine yield of 74.6% (based on β-O-4 units) is achieved. Compatibility with various nitrogen sources, including substituted nitroaromatics and nitrogen oxides (NOx), is also investigated. This work demonstrates the possibility of using lignin as a sustainable alternative to petroleum-based synthesis of nitrogen-containing aromatic compounds.

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Fig. 1: Optimization of paired electrodes and evaluation of electrolysis performance.
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Fig. 2: Electrolyte engineering for paired electrocatalytic C–N coupling of PPE and NBz.
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Fig. 3: MD simulations of local proton distribution.
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Fig. 4: Structural characterization of the Pd1/TivO2-NS catalyst.
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Fig. 5: In situ Raman spectroscopy and EQCM analysis of adsorption behaviour.
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Fig. 6: Mechanistic investigation of the paired electrocatalytic C–N coupling reaction.
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Fig. 7: Substrate scope and generality of the paired electrocatalytic system.
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Supporting data for the study are available in this article and its Supplementary Information. Source data are provided with this paper.

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Acknowledgements

This work was supported by the National Key R&D Program of China (grant no. 2023YFA1507400) and the National Natural Science Foundation of China (grant nos. U24A20498 and 22425021).

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Author notes

  1. These authors contributed equally: Yuanqing He, Shiheng Mo, Xu Zeng, Yuhao Zhang, Ta Thi Thuy Nga.

Authors and Affiliations

  1. State Key Laboratory of Chemo and Biosensing, College of Chemistry and Chemical Engineering, International Joint Lab of Energy Electrochemistry of the Ministry of Education, Hunan University, Changsha, China

    Yuanqing He, Shiheng Mo, Yulu Yang, Zhuoran Lu, Yajing Zhang, Zhongcheng Xia, Shuangyin Wang & Yuqin Zou

  2. Academy of Advanced Carbon Conversion Technology, Huaqiao University, Xiamen, China

    Xu Zeng

  3. National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, China

    Yuhao Zhang & Qinghua Liu

  4. Department of Physics, Tamkang University, New Taipei City, Taiwan

    Ta Thi Thuy Nga & Chung-Li Dong

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Contributions

Y. Zou and S.W. conceived the idea and directed the research. Y.H. designed the experiments. Y.H., S.M. and X.Z. performed research; Y.H. and Yajing Zhang contributed to the theoretical calculations. Z.L., Y.Y. and Z.X. analysed data; Yuhao Zhang and Q.L. performed SR–FTIR measurements; T.T.T.N. and C.-L.D. performed XANES measurements. Y. Zou and Y.H. wrote the paper. All authors have approved the final version of the paper.

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Correspondence to Shuangyin Wang or Yuqin Zou.

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Nature Synthesis thanks Haohong Duan, Jason Chun-Ho Lam and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: Eric Piechota, in collaboration with the Nature Synthesis team.

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He, Y., Mo, S., Zeng, X. et al. Paired electrolysis enables selective C–N coupling for the synthesis of nitrogenous aromatics. Nat. Synth (2026). https://doi.org/10.1038/s44160-026-01057-w

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