Article · Wikipedia archive · Last revised Jun 22, 2026

Cupferron

Cupferron is jargon for the ammonium salt of the conjugate base derived from N-nitroso-N-phenylhydroxylamine. This conjugate base is abbreviated as CU−. It once was a common reagent for the complexation of metal ions, being of interest in the area of qualitative inorganic analysis. Its formula is NH4[C6H5N(O)NO]. The anion binds to metal cations through the two oxygen atoms, forming five-membered chelate rings.

Last revised
Jun 22, 2026
Read time
≈ 2 min
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Citations
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Source
Wikipedia ↗
Cupferron
Cupferron
Cupferron source ↗
Names
Other names
cupferron
ammonium N-nitrosophenylhydroxylamine
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.004.713
EC Number
  • 205-183-2
UNII
  • InChI=1S/C6H5N2O2.H3N/c9-7-8(10)6-4-2-1-3-5-6;/h1-5H;1H3/q-1;/p+1 checkY
    Key: GDEBSAWXIHEMNF-UHFFFAOYSA-O checkY
  • InChI=1/C6H5N2O2.H3N/c9-7-8(10)6-4-2-1-3-5-6;/h1-5H;1H3/q-1;/p+1
    Key: GDEBSAWXIHEMNF-IKLDFBCSAP
  • O=NN([O-])c1ccccc1.[NH4+]
Properties
C6H9N3O2
Molar mass 155.157 g·mol−1
Melting point 150 to 155 °C (302 to 311 °F; 423 to 428 K)
Soluble
Hazards
GHS labelling:
GHS06: ToxicGHS07: Exclamation markGHS08: Health hazard
Danger
H301, H315, H319, H335, H351
P201, P202, P261, P264, P270, P271, P280, P281, P301+P310, P302+P352, P304+P340, P305+P351+P338, P308+P313, P312, P321, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Cupferron is jargon for the ammonium salt of the conjugate base derived from N-nitroso-N-phenylhydroxylamine. This conjugate base is abbreviated as CU−. It once was a common reagent for the complexation of metal ions, being of interest in the area of qualitative inorganic analysis. Its formula is NH4[C6H5N(O)NO]. The anion binds to metal cations through the two oxygen atoms, forming five-membered chelate rings.

Synthesis and complexes

Structure of ferric cupferron complex source ↗

Cupferron is prepared from phenylhydroxylamine and an NO+ source:1

C6H5NHOH + C4H9ONO + NH3 → NH4[C6H5N(O)NO] + C4H9OH

Being a bidentate mono-anionic ligand, CU− forms complexes analogous to those produced with acetylacetonate. Illustrative complexes include Cu(CU)2, Fe(CU)3, and Zr(CU)4.234

See also

See also

References

References

  1. C. S. Marvel (1925). "Cupferron". Organic Syntheses. 4: 19. doi:10.15227/orgsyn.004.0019.
  2. Elerman, Y.; Atakol, O.; Svoboda, I.; Geselle, M. (1995). "Bis(cupferronato)copper(II), [Cu(C6H5N2O2)2]". Acta Crystallographica Section C Crystal Structure Communications. 51 (8): 1520–1522. doi:10.1107/S0108270195002770.
  3. Van Der Helm, D.; Merritt, L. L.; Degeilh, R.; MacGillavry, C. H. (1965). "The Crystal Structure of IIron Cupferron Fe(O2N2C6H5)3". Acta Crystallographica. 18 (3): 355–362. doi:10.1107/S0365110X65000816.
  4. Mark, Wanda; Aava, Ulf; Haaland, A.; Resser, Dag; Rasmussen, S. E.; Sunde, Erling; Sørensen, Nils Andreas (1970). "The Crystal Structure of Zirconium Cupferrate, Zr(C6H5N2O2)4". Acta Chemica Scandinavica. 24: 1398–1414. doi:10.3891/acta.chem.scand.24-1398.