Copper complexes cupferron

Cupferron (29), as the name suggests, has been applied to the analytical determination of copper and iron. In neutral solution, a white 1 1 complex with Ag1 has been obtained which reacted with Mel to give the methyl ether.292 Reaction of the related ligand (30) with silver nitrate in aqueous methanol gave a red predpitate which on further reaction with Mel gave the methyl ether in a reaction analogous to that for cupferron.293... 

Complexes of neocupferron, the ammonium salt of Ar-nitroso-Ar-2-naphthylhydroxylamine (16 Ar = naphthyl) are less soluble and bulkier than those of cupferron and can be used to determine copper and iron from the sea and natural waters without a preliminary concentration stage. 

Soon after the introduction of dimethylglyoxime as a specific reagent for nickel by Tschugaeff-Kraut-Brunck (1905-1907), Baudisch discovered a compound which precipitates copper and iron quantitatively from acid solutions.82 He appropriately named this reagent as cupferron . It is the water soluble ammonium salt of nitrosophenylhydroxylamine (5). When dissolved in chloroform, the whitish-grey copper compound gives a bright yellow solution and the brown yellow iron(III) compound a deep red solution. This behaviour reveals the inner complex character of these derivatives (6). 

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