The metal-complexing properties of N-benzoyl-N-phenylhydroxylamine derivatives containing N-phenyl ring substituents

The syntheses and chelating properties of a number of N-benzoyl-N-phenylhydroxyl-amine derivatives substituted in the N-phenyl ring have been investigated. The acid dissociation constants, selective precipitation, solvent extraction and spectrophotometric properties of a range of metal chelates are compared with those of the corresponding 3,5-dinitrobenzoylphenylhydroxylamines. The N-phenyl ring substituents have only small effects on reagent acidity. If the substituents are in the ortho position, considerable selectivity is found because of steric hindrance. The use of an o-chloro derivative as a selective precipitant for iron(III) in the presence of cobalt, nickel, copper and aluminium, is described.