Pulse and γ-radiolysis studies on aqueous solution of 1,1′-dimethyl-2-selenourea

Abstract

One-electron oxidation of 1,1′-dimethyl-2-selenourea (DMSeU) by hydroxyl radicals, one-electron-specific oxidants, was studied using pulse radiolysis technique in aqueous solution. Hydroxyl ( OH) radicals and one-electron oxidants, N 3 , X 2 − (X=Cl, Br, and I) react with DMSeU to form a transient having an absorption spectrum with λ max at 430 nm. By following the absorbance at 430 nm as a function of solute concentration and in analogy with similar sulfur and selenium compounds, this transient is assigned to dimer radical cation. The dimer radical cations of DMSeU react with oxygen with bimolecular rate constant of 1.0±0.3×10 8 M −1 s −1. Steady-state γ-radiolysis studies on aqueous solution of DMSeU under hydroxyl radical-induced oxidation condition indicated formation of elemental selenium as one of the by-products, which has been stabilized by the addition of poly vinyl alcohol (PVA), and characterized by dynamic light scattering technique.