COMPARATIVE-STUDY OF THE CHELATION REACTION OF N-BENZOYL-N-PHENYLHYDROXYLAMINE WITH TIN(II) AND TIN(IV)

A comparative study by elemental analysis, differential scanning therm al analysis, X-ray photoelectron spectrometry, H-1 NMR spectrometry an d infrared spectrometry revealed that the product of reaction of N-ben zoyl-N-phenylhydroxylamine (BPHA) with Sn-II is identical with that wi th Sn-IV and that BPHA acts merely as a chelating ligand, neither oxid izing Sn-II nor reducing Sn-IV. A reaction mechanism is proposed. The use of BPHA in a large excess facilitates the dissociation of anionic chlorocomplexes of Sn to the active species SnCl22+ on the one hand, a nd shifts the redox equilibrium of Sn-II-Sn-IV on the other, favouring the Sn-IV state.