Light-driven depolymerization of native lignin enabled by proton-coupled electron transfer

Suong T. Nguyen, Philip R.D. Murray, Robert R. Knowles

Research output: Contribution to journalArticlepeer-review

75 Scopus citations


Here, we report a catalytic, light-driven method for the redox-neutral depolymerization of native lignin biomass at ambient temperature. This transformation proceeds via a proton-coupled electron-Transfer (PCET) activation of an alcohol O-H bond to generate a key alkoxy radical intermediate, which then facilitates the β-scission of a vicinal C-C bond. Notably, this single-step depolymerization is driven solely by visible-light irradiation, requires no stoichiometric chemical reagents, and produces no stoichiometric waste. This method exhibits good efficiency and excellent selectivity for the activation and fragmentation of the β-O-4 linkage in the polymer backbone, even in the presence of numerous other PCET-Active functional groups. The feasibility of this protocol in enabling the cleavage of the β-1 linkage in model lignin dimers was also demonstrated. These results provide further evidence that visible-light photocatalysis can serve as a viable method for the direct conversion of lignin biomass into valuable arene feedstocks.

Original languageEnglish (US)
Pages (from-to)800-805
Number of pages6
JournalACS Catalysis
Issue number1
StatePublished - Jan 3 2020

All Science Journal Classification (ASJC) codes

  • Catalysis
  • General Chemistry


  • C-C bond cleavage
  • alkoxy radicals
  • lignin depolymerization
  • photoredox catalysis
  • proton-coupled electron transfer


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