A quantum chemical study of the mechanism of thermal decomposition of N′-methoxy-N-methyldiazene N-oxide

• Published in: Russian chemical bulletin 2022-12, Vol.71 (12), p.2595-2604
• Main Authors: Nikolaeva, E. V., Aristov, I. V., Chachkov, D. V., Khrapkovskii, G. M., Shamov, A. G.
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Decomposition reactions; Enthalpy; Full Articles; Inorganic Chemistry; Isomerization; Organic Chemistry; Oxygen atoms; Quantum chemistry; Thermal decomposition
• ISSN: 1066-5285; 1573-9171
• DOI: 10.1007/s11172-022-3688-7

Alternative primary reactions of thermal decomposition of N′ -methoxy- N -methyldiazene N -oxide ( 1 ) to the experimentally observed products under normal conditions and the average experimental temperature were studied using the density functional methods PBE, B3LYP, wB97XD, wB97X with different basis sets and the composite method G4. All methods gave qualitatively consistent results. Based on these results and a detailed PBE/L11 and B3LYP/6-31G (2df, p) study of various secondary processes, it was concluded that the most energetically advantageous and, hence, the most likely channel of thermal decomposition of 1 involves the isomerization of the latter by rotation of the MeO group around the NO bond followed by the transfer of the Me group between oxygen atoms. The enthalpy of activation of the Me group transfer obtained by all the methods used agrees well with the experimentally obtained value, and this reaction is the limiting step of the entire process of thermal decomposition of 1 .