View source for Chemistry:Α-O

{{short description|Reactive oxygen species}}
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'''α-O''' (''alpha''-oxygen) is a [[Biology:Reactive oxygen species|reactive oxygen species]] formed from an oxygen-atom abstraction (OAT) from [[Chemistry:Nitrous oxide|nitrous oxide]] (N<sub>2</sub>O) by alpha-[[Chemistry:Iron|iron]] (α-Fe) [[Chemistry:Catalysis|catalysts]]. The latter is defined as a high spin (S=2) divalent iron(II) ion in a constrained [[Physics:Square planar molecular geometry|square planar]] coordination with an accessible axial coordination position. The stabilization of α-O requires structural strain on the equatorial ligand field to maintain the reactive oxygen atom in the axial position and it is this forced geometry, similar to the '[[Biology:Entatic state|entatic state]]' known in metalloproteins, that lies at the basis of its reactivity in inert C-H bond activation.<ref name="Snyder 2016">{{cite journal |vauthors= Snyder BE, Vanelderen P, Bols ML, Hallaert SD, Böttger LH, Ungur L, Pierloot K, Schoonheydt RA, Sels BF, Solomon EI |title= The active site of low-temperature methane hydroxylation in iron-containing zeolites |journal= Nature |volume= 536 |issue= 7616 |pages= 317–21 |date= August 2016 |pmid= 27535535 |doi= 10.1038/nature19059|bibcode= 2016Natur.536..317S |s2cid= 4467834 }}</ref>

The alpha-oxygen site was first discovered and named in 1990 by researchers from the [[Organization:Boreskov Institute of Catalysis|Boreskov Institute of Catalysis]] in the [[Chemistry:ZSM-5|ZSM-5]] zeolite,<ref>{{cite journal |vauthors= Pannov GI, Sobolev VI, Kharitonov AS |title=The role of iron in N2O decomposition on ZSM-5 zeolite and reactivity of the surface oxygen formed |journal=Journal of Molecular Catalysis |date=July 1990 |volume=61 |issue=1 |pages=85–97 |doi=10.1016/0304-5102(90)85197-P}}</ref><ref>{{cite journal |vauthors= Sobolev V |title=Catalytic Properties of ZSM-5 Zeolites in N2O Decomposition: The Role of Iron |journal=Journal of Catalysis |date=February 1993 |volume=139 |issue=2 |pages=435–443 |doi=10.1006/jcat.1993.1038}}</ref> and was later described in detail by researchers from [[Organization:Stanford University|Stanford University]] and KU Leuven in the beta zeolite.<ref name="Snyder 2016"/><ref>{{cite journal |vauthors= Hallaert SD, Bols ML, Vanelderen P, Schoonheydt RA, Sels BF, Pierloot K |title= Identification of α-Fe in High-Silica Zeolites on the Basis of ab Initio Electronic Structure Calculations |language= EN |journal= Inorganic Chemistry |volume= 56 |issue= 17 |pages= 10681–10690 |date= September 2017 |pmid= 28836775 |doi= 10.1021/acs.inorgchem.7b01653|url= https://lirias.kuleuven.be/handle/123456789/592553 }}</ref><ref>{{cite journal |vauthors= Snyder BE, Böttger LH, Bols ML, Yan JJ, Rhoda HM, Jacobs AB, Hu MY, Zhao J, Alp EE, Hedman B, Hodgson KO, Schoonheydt RA, Sels BF, Solomon EI |title= Structural characterization of a non-heme iron active site in zeolites that hydroxylates methane |journal= Proceedings of the National Academy of Sciences of the United States of America |volume= 115 |issue= 18 |pages= 4565–4570 |date= May 2018 |pmid= 29610304 |pmc= 5939097 |doi= 10.1073/pnas.1721717115|doi-access= free }}</ref>

==See also==
*[[Chemistry:Carbon–hydrogen bond activation|Carbon–hydrogen bond activation]]
*[[Chemistry:Catalysis|Catalysis]]

==References==
{{Reflist}}

[[Category:Reactive oxygen species]]
[[Category:Reactive intermediates]]

{{Sourceattribution|Α-O}}