The Reactions of Bromide with Ozone Towards Bromate and the Hypobromite Puzzle: A Density Functional Theory Study

Taking the solvent water into account, the energetics of the reactions of O3 with Br− leading to BrO3 − have been calculated by Density Functional Theory at the B3LYP/6–311+G(d)/SCRF =COSMO level. Br− reversibly forms an adduct, BrOOO−, (ΔG = +6 kJ mol−1) that decays spin allowed into BrO− and O2(1Δg) (ΔG = +13 kJ mol−1). BrO− undergoes an oxidation to BrO2 − and a reduction to Br−. This may be accounted for if two different adducts, OBrOOO− and BrOOOO−, decay into BrO− plus O2 and Br− plus 2 O2. After cyclization, OBrOOO− may also lead to Br− plus 2 O2.