Criegee intermediate

Not to be confused with Criegee oxidation or Criegee rearrangement.
Criegee zwitterion

A Criegee intermediate (also called a Criegee zwitterion or Criegee biradical) is a carbonyl oxide with two charge centers. These chemicals may react with sulfur dioxide and nitrogen oxides in the Earth's atmosphere, and are implicated in the formation of aerosols, which are an important factor in controlling global climate.[1][2] Criegee intermediates are also an important source of OH (hydroxyl radicals).[3] OH radicals are the most important oxidant in the troposphere,[4] and are important in controlling air quality and pollution.

The formation of this sort of structure was first postulated in the 1950s by Rudolf Criegee,[5] for whom it is named. It was not until 2012 that direct detection of such chemicals was reported.[6] Infrared spectroscopy suggests the electronic structure has a substantially zwitterionic character rather than the biradical character that had previously been proposed.[7]

  1. ^ Welz, Oliver; Savee, John D.; Osborn, David L.; Vasu, Subith S.; Percival, Carl J.; Shallcross, Dudley E.; Taatjes, Craig A. (13 January 2012). "Direct Kinetic Measurements of Criegee Intermediate (CH2OO) Formed by Reaction of C2I with O2". Science. 335 (6065): 204–207. Bibcode:2012Sci...335..204W. doi:10.1126/science.1213229. PMID 22246773. S2CID 26810853.
  2. ^ Castro, Joseph (January 12, 2012). "How mysterious molecules may help cool Earth". NBC News. Retrieved 2012-01-12.
  3. ^ Heard, Dwayne E.; Whalley, Lisa K.; Stone, Daniel (2012). "Tropospheric OH and HO2 radicals: field measurements and model comparisons". Chemical Society Reviews. 41 (19): 6348–6404. doi:10.1039/C2CS35140D. PMID 22907645.
  4. ^ Finlayson-Pitts, Barbara J.; Pitts, James N. (2000). Chemistry of the upper and lower atmosphere : theory, experiments, and applications. San Diego: Academic Press. ISBN 9780080529073. OCLC 162128929.
  5. ^ "Offsetting Global Warming: Molecule in Earth's Atmosphere Could 'Cool the Planet'". Science Daily. January 12, 2012. Retrieved 2012-01-14.
  6. ^ Taatjes, Craig A.; Shallcross, Dudley E.; Percival, Carl J.; Vasu, Subith S.; Osborn, David L.; Savee, John D.; Welz, Oliver (2012-01-13). "Direct Kinetic Measurements of Criegee Intermediate (CH2OO) Formed by Reaction of CH2I with O2". Science. 335 (6065): 204–207. Bibcode:2012Sci...335..204W. doi:10.1126/science.1213229. ISSN 1095-9203. PMID 22246773. S2CID 26810853.
  7. ^ Su, Yu-Te; Huang, Yu-Hsuan; Witek, Henryk A.; Lee, Yuan-Pern (12 April 2013). "Infrared Absorption Spectrum of the Simplest Criegee Intermediate CH2OO". Science. 340 (6129): 174–176. Bibcode:2013Sci...340..174S. doi:10.1126/science.1234369. PMID 23580523. S2CID 31499893.