Kinetics of the oxidation of hydrogen azide (hydrazoic acid) by bis(2,2′-bipyridine)manganese(III) ions in aqueous perchlorate media

Abstract

On mixing HN₃ with solutions containing [Mn(bipy)₂]³⁺(aq)(bipy = 2,2′-bipyridine) the absorbance at 400 nm first increases before decreasing to zero. The analysis of the absorption coefficient extrapolated to zero time for the rise in absorbance shows that two 1 : 1 complexes are formed between N₃^– and [Mn(bipy)₂]³⁺. The kinetics of the subsequent decay in absorbance shows that both these complexes, [Mn(bipy)₂(N₃)]²⁺ and [Mn(bipy)₂(OH)(N₃)]⁺, are involved in the oxidation process producing free radicals N₃˙. This oxidation is compared with the kinetics of the oxidation of HN₃ by aqua cations and by [Ni(bipy)₃]³⁺.