Pulse radiolysis study on radical cations of alkyl bromides in aqueous solutions

Abstract

The transient optical absorption bands formed on reaction of ˙OH radicals with 1,m-dibromoalkanes and n-alkyl bromides in acidic aqueous solutions have been assigned to intra-, [graphic omitted], and inter-molecular, (RBr∴BrR)⁺, radical cations, respectively. Depending upon R, these radical cations exhibit an optical absorption band in the 385–450 nm region. Increases in the chain length and electron-releasing power of R results in a red shift of λ_max and a decrease in the lifetime. These radical cations are strong oxidants and oxidize various substrates with bimolecular rate constants of the order of 10⁹ dm³ mol^–1 s^–1.