Kinetics of reactions of Schiff base complexes of iron(II). Part II. Reactions of substituted tris-[N-(2-pyridylmethylene)aniline]complexes with bases and with hydrogen peroxide

Abstract

Kinetics of reactions of substituted tris-[N-(2-pyridylmethylene)aniline]iron(II) complexes with hydrogen peroxide, with 2,2′-bipyridyl and related compounds, and with hydroxide ion are reported. Reaction with hydrogen peroxide proceeds by rate-determining loss of one ligand molecule, as in acid fission, followed by rapid reaction of intermediates with hydrogen peroxide. Reaction with 2,2′-bipyridyl also proceeds by rate-determining loss of one ligand molecule followed by complete conversion into the tris-(2,2′-bipyridyl)iron(II) complex. Reaction with hydroxide ion occurs partly by dissociation and partly by direct nucleophilic attack. Correlation of substituent effects on the rates for hydroxide attack with Hammett σ-values is described. Finally, reactions of nitro- and related substituent complexes, which behave anomalously in acid fission, are discussed.