Computational study of the stability of α-nitroxy-substituted alkyl radicals

The impact of nitroxy-substituents, –ONO2, on the dominant chemical reactions in the atmosphere is still not fully understood. A theoretical DFT and coupled cluster theory analysis of alkyl radicals with nitroxy-substituents on the radical carbon revealed that such radicals are unstable, dissociating by O–N bond scission and leading to a carbonyl compound and NO2. This dissociation occurs sequentially after completion of the reaction forming the α-nitroxy-substituted alkyl radical, such that the formation process is independent of the subsequent O–N bond scission. The presence of a β-nitroxy substituent in alkoxy radicals decreases the barrier to decomposition by 12 kJ mol−1.