Radiation Chemical Studies of Nickel-Glycine. Hydrogen Abstraction by OH Radicals and Oxidation by Br2-1

Article abstract of DOI:10.1021/j150611a013

Reactions of hydroxyl radicals with Ni(II)-glycine complexes were studied by pulse radiolysis and by product analysis.Radiolytic degradation of the complexes in N2O-saturated solutions leads to the formation of carbonyl compounds.The nature and the yield of these products indicate that the transient formed by reaction of OH with the complex undergoes disproportionation.The optical absorption spectrum of this transient exhibits a maximum below 250 nm, which is similar to that observed with glycine alone.The reaction of Br2^- with the complex is found to be too slow to be observed by pulse radiolysis.However, the reaction occurs in steady-state radiolysis and yield products different from those observed with OH.Specifically, the yield of formaldehyde is appreciably higher in the presence of Br^-.It is concluded that Br2^- oxidizes the metal center of the Ni(II)-glycine complex to Ni(III), whereas OH reacts by hydrogen abstraction to form Ni(II)-coordinated glycine radical.