Pulse and γ-radiolysis of nickel(II) nitrilotriacetate in aqueous solutions

Abstract

The radiolysis of the title complex [Ni(nta)]^– has been studied by pulse radiolysis and by product analysis after γ-radiolysis. Hydroxide radicals abstract a hydrogen from the ligand of the complex, k=(1.2 ± 0.1)× 10⁹ dm³ mol^–1 s^–1, to give complex radicals which react with various metal ions such as Cu²⁺, Ir^IV, and Ni²⁺ and in their absence with [Ni(nta)]^– by electron transfer. Reaction of O₂ with the radicals is comparatively slow, k=(3.9 ± 0.4)× 10³ dm³ mol^–1 s^–1. Ligand-oxidation products and their yields are consistent with the mechanisms of the reactions suggested. Hydrated electrons reduce the complex to [Ni(nta)]^2–, k=(1.5 ± 0.1)× 10⁹ dm³ mol^–1 s^–1, which rapidly disappears through a bimolecular reaction, 2k=(1.5 ± 0.1)× 10⁹ dm³ mol^–1 s^–1, which is independent of pH in the range 5–9.