3(4)-Amino-4(3)-nitro-1,2,5-oxadiazole-2-oxides and their Ring-opened Isomers-A DFT Treatment

Abstract

Amino and nitro substituted 1,2,5-oxadiazole-2-oxide isomers and their ring-opened nitroso forms have been subjected to density functional treatment at the level of B3LYP/6-311++G(d,p). The transition states for the ring opening processes are obtained and the corresponding activation energies have been calculated. Also, 1,3- and 1,5-proton tautomerism yielding imine, oxime and aci forms are investigated. For all the structures, the stabilities, the HOMO, LUMO energies and the interfrontier molecular orbital energy gaps are obtained and the effects of substituents (NH2 and NO2) are discussed.