Kinetics of complex formation between 1-(2-hydroxyphenyl)-3,5-diphenylformazan and ammineaquacopper(II) complexes

A kinetic study is reported on the reaction between copper(II) perchlorate and the tridentate ligand 1-(2-hydroxyphenyl)-3,5-diphenylformazan in ammoniacal ethanol–water mixtures at constant ionic strength. A detailed analysis of medium effects has resulted in the elucidation of the mechanism of the reaction. Coordination of an amminecopper(II) complex to the formazan is shown to occur in discrete steps. A rather stable bicoordinated intermediate could be studied in solution. A comparison with earlier results has clarified some of the factors that determine the attack of metal ions on the formazans.