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Dioxygen & Related Ligands

  1. Prof. Rebecca R. Conry

Published Online: 15 MAR 2006

DOI: 10.1002/0470862106.ia066

Encyclopedia of Inorganic Chemistry

Encyclopedia of Inorganic Chemistry

How to Cite

Conry, R. R. 2006. Dioxygen & Related Ligands . Encyclopedia of Inorganic Chemistry. .

Author Information

  1. Colby College, Waterville, ME, USA

Publication History

  1. Published Online: 15 MAR 2006


Metal–dioxygen interactions are important in the activation of dioxygen by aerobic organisms and in other processes that utilize dioxygen, for instance, in catalytic oxygenation reactions. Most d-block metals have been found to interact with dioxygen and many dioxygen-containing complexes have been isolated. A number of binding modes have been found in these complexes, including the simple binding of one O2 molecule to one metal center and systems where the O2 moiety bridges two or more metal ions. Some reduction of dioxygen occurs upon binding; thus, these complexes are generally regarded as containing superoxide (one-electron reduced) or peroxide (two-electron reduced) ligands, which are typically spectroscopically distinguished. In general, superoxo complexes exhibit υ(O[BOND]O) in their infrared or Raman spectra between about 960 and 1200 cm−1 and usually contain planar metal2–O2 units for dinuclear complexes, whereas peroxide complexes result in υ(O[BOND]O) between about 650 and 950 cm−1 and the dinuclear complexes typically have nonplanar metal2–O2 units. Examples of superoxo and peroxo complexes for the different binding modes are discussed, including the discovery that some dinuclear metal–dioxygen complexes [M[BOND](O2)[BOND]M; M = metal] are in equilibrium with bis-μ-oxo complexes [M[BOND](O)2[BOND]M; i.e. the O[BOND]O bond is no longer present].


  • dioxygen;
  • oxygen;
  • peroxide;
  • peroxo;
  • superoxide;
  • superoxo;
  • oxidation