Singly Reduced Iridium Chromophores: Synthesis, Characterization, and Photochemistry

Yunjung Baek, Adam Reinhold, Lei Tian, Philip D. Jeffrey, Gregory D. Scholes, Robert R. Knowles

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


One-electron reduced photosensitizers have been invoked as crucial intermediates in photoredox catalysis, including multiphoton excitation and electrophotocatalytic processes. However, such reduced chromophores have been less investigated, limiting mechanistic studies of their associated electron transfer processes. Here, we report a total of 11 different examples of isolable singly reduced iridium chromophores. Chemical reduction of a cyclometalated iridium complex with potassium graphite affords a 19-electron species. Structural and spectroscopic characterizations reveal a ligand-centered reduction product. The reduced chromophore absorbs a wide range of light from ultraviolet to near-infrared and exhibits photoinduced bimolecular electron transfer reactivity. These studies shed light on elusive reduced iridium chromophores in both ground and excited states, providing opportunities to investigate a commonly invoked intermediate in photoredox catalysis.

Original languageEnglish (US)
Pages (from-to)12499-12508
Number of pages10
JournalJournal of the American Chemical Society
Issue number23
StatePublished - Jun 14 2023

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Biochemistry
  • Catalysis
  • Colloid and Surface Chemistry


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