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.

Cupferron

Cupferron
Names
Other names cupferron ammonium N-nitrosophenylhydroxylamine
Identifiers
CAS Number	135-20-6 Y
3D model (JSmol)	Interactive image
ChemSpider	2006262 Y
ECHA InfoCard	100.004.713
EC Number	205-183-2
PubChem CID	2724103
UNII	V66QK963ED Y
CompTox Dashboard (EPA)	DTXSID1020352
InChI InChI=1S/C6H5N2O2.H3N/c9-7-8(10)6-4-2-1-3-5-6;/h1-5H;1H3/q-1;/p+1 Y Key: GDEBSAWXIHEMNF-UHFFFAOYSA-O Y 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
SMILES O=NN([O-])c1ccccc1.[NH4+]
Properties
Chemical formula	C6H9N3O2
Molar mass	155.157 g·mol−1
Melting point	150 to 155 °C (302 to 311 °F; 423 to 428 K)
Solubility in water	Soluble
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H315, H319, H335, H351
Precautionary statements	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). Y verify (what is YN ?) Infobox references

Synthesis and complexes

Structure of ferric cupferron complex

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.^[2][3][4]