Hyponitrite

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Bis(hyponitrite)
Names
Preferred IUPAC name
Hyponitrite
Systematic IUPAC name
Diazenebis(olate)
Other names
Hyponitrite(2-)
Identifiers
3D model (JSmol)
3DMet B00354
ChEBI
ChemSpider
130273
KEGG
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

In chemistry, hyponitrite may refer to the anion N
2
O2−
2
([ON=NO]2−), or to any ionic compound that contains it. In organic chemistry, it may also refer to the group -O-N=N-O-, or any organic compound with the generic formula R1-O-N=N-O-R2, where R1 and R2 are organic groups.[1] Such compounds can be viewed as salts and esters, respectively, of hyponitrous acid H
2
N
2
O
2
or HON=NOH.

An acid hyponitrite is an ionic compound with the anion HN
2
O
2
([HON=NO]).

Hyponitrite ion[edit]

Hyponitrite exhibits cis–trans isomerism.[2]

The trans (E) form is generally found in hyponitrite salts such as sodium hyponitrite, Na
2
N
2
O
2
and silver(I) hyponitrite, Ag
2
N
2
O
2
.

The cis (Z) form of sodium hyponitrite can be obtained too, and it is more reactive than the trans form.[2] The cis hyponitrite anion is nearly planar and almost symmetric, with lengths of about 140 pm for N-O bond and 120 pm for the N-N bond, and O-N-N angles of about 119 degrees.[3]

Reactions[edit]

The hyponitrite ions can act as a bidentate ligand in either bridging or chelating mode. There is a bridging cis-hyponitrite group in the red dinuclear form of nitrosyl pentammine cobalt(III) chloride, [Co(NH3)5NO]Cl2.[4]

Hyponitrite can act as a reducing agent for example reducing iodine:[4]

N
2
O2−
2
+ 3 I
2
+ 3 H
2
O
NO
3
+ NO
2
+ 6 HI

Hyponitrite esters[edit]

Organic trans-hyponitrites R1–O–N=N–O–R2 can be obtained by reacting trans silver(I) hyponitrite Ag
2
N
2
O
2
with various alkyl halides. For example, reaction with t-butyl chloride yields trans di-tert-butyl hyponitrite.[5][6][7][8]

Other alkyl radicals reported in the literature include ethyl,[9] and benzyl,.[10][11][12] These compounds can be a source of alkoxyl radicals.[13]

See also[edit]

Other nitrogen oxoanions include

References[edit]

  1. ^ M. N. Hughes (1968), "Hyponitrites". Quarterly Reviews of the Chemical Society, volume 22, issue 1, pages 1-13. doi:10.1039/QR9682200001
  2. ^ a b Egon Wiberg, Arnold Frederick Holleman (2001) Inorganic Chemistry, Elsevier ISBN 0-12-352651-5
  3. ^ Claus Feldmann, Martin Jansen (1996), "cis-Sodium Hyponitrite - A New Preparative Route and a Crystal Structure Analysis". Angewandte Chemie International Edition in English, volume 35, issue 15, pages 1728–1730. doi:10.1002/anie.199617281
  4. ^ a b Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0-08-037941-9. 
  5. ^ Navamoney Arulsamy; D. Scott Bohle; Jerome A. Imonigie; Elizabeth S. Sagan (2000). "Correlation of the Product E/Z Framework Geometry and O/O vs O/N Regioselectivity in the Dialkylation of Hyponitrite". J. Am. Chem. Soc. 122 (23): 5539–5549. doi:10.1021/ja994261o. 
  6. ^ H. Kiefer and T. G. Traylor (1966), Tetrahedron Lett., page 6163.
  7. ^ R. L. Huang, T. W. Lee, and S. H. Ong (1969), J. Chem. Soc. C, page 40.
  8. ^ R. C. Neuman and R. J. Bussey (1970), J. Amer. Chem. Soc., volume 92, page 2440.
  9. ^ J. R. Partington and C. C. Shah (1932), J. Chem. Soc., page 2589.
  10. ^ J. B. Sousa and S. K. Ho (1961), J. Chem. Soc., page 1788.
  11. ^ J. B. Sousa and S. K. Ho (1960), Nature, volume 186, page 776.
  12. ^ N. H. Ray (1960), J. Chem. Soc., page 4023.
  13. ^ Craig A. Ogle; Steven W. Martin; Michael P. Dziobak; Marek W. Urban; G. David Mendenhall (1983). "Decomposition rates, synthesis, and spectral properties of a series of alkyl hyponitrites". J. Org. Chem. 48 (21): 3728–3733. doi:10.1021/jo00169a023.