Insight into the acidic group-induced nitration mechanism of 2-methyl-4,6-dihydroxypyrimidine (MDP) with nitronium

Abstract

The strong desire for developing promising candidates of insensitive nitro energetic materials has spurred numerous attempts to discern the nitration details. The nitration mechanism of 2-methyl-4,6- expected that the present study may provide a theoretical basis to the research and engineering tests of the title nitration, and promote the exploration of related insensitive energetic materials.

Impact of the acidic group on the hydrolysis of 2-dinitromethylene-5,5-dinitropyrimidine-4,6-dione

“…Most of the computational details in the geometry investigation in the present work are very similar to those in our recent report. 12,13 The calculations were carried out using the Gaussian 09 soware package. 22 DFT-B3LYP/6-311G(d,p) 23,24 has been used in similar systems.…”

“…22 DFT-B3LYP/6-311G(d,p) 23,24 has been used in similar systems. 12,[25][26][27][28] The accuracy of this method was evaluated and veried, as shown in the ESI (Table S1). † Thus, B3LYP/6-311G(d,p) was intentionally employed to optimize the geometries of the reactant complexes, transition states, intermediates and products of the hydrolysis of NMP.…”

“…Recently, we employed a density functional theory (DFT) method to elucidate the nitration of MDP in the mixed acids, in which a coexisting HSO 4 À induced/promoted nitration mechanism was presented, via which the formation of the key intermediate NMP was discerned. 12 Such induction/promotion of HSO 4 À was also illustrated in the nitration of triazol-3-one (TO). 13 (in Angstroms) of FOX-7 using multiple methods; the calculated single point energy and activation free energy (DG s ) using multiple methods for the rst step in the direct hydrolysis of NMP in the formamide phase; the optimized geometries of reactant NMP; potential energy diagrams for the internal rotation of the dihedral angles in NMP; the optimized geometries of species in the direct hydrolysis of NMP calculated at the B3LYP/6-311G(d,p) level with the CPCM model in the gas, formamide, and DMSO phases; the optimized geometries of species in H 2 O catalyzed hydrolysis of NMP calculated at the B3LYP/6-311G(d,p) level with the CPCM model in the gas, formamide, and DMSO phases; the optimized geometries of species in HSO 4…”

“…Recently, we employed a density functional theory (DFT) method to elucidate the nitration of MDP in the mixed acids, in which a coexisting HSO 4 − induced/promoted nitration mechanism was presented, via which the formation of the key intermediate NMP was discerned. 12 Such induction/promotion of HSO 4 − was also illustrated in the nitration of triazol-3-one (TO). 13 Moreover, the impact of the solvent effects of the mixed acids on nitration was also studied.…”

“…By comparing the calculated activation free energy (DG s ) in the formamide, DMSO, and gas phases, we found that the solvent effects on the nitration of MDP may be inapparent/weak. 12 Based on such calculations, we suppose that the coexisting HSO 4…”