Molecular structure, the quantum chemical investigation and the thermal behavior of the dimethylamine salt of 3-nitro-1,2,4-triazol-5-one, (CH3)2NH2+C2N4O3H$minus;

Abstract

(CH 3 ) 2 NH 2 + C 2 N 4 O 3 H − was prepared by mixing the NTO ethanol solution and the dimethylamine aqueous solution. Single crystals suitable for X-ray measurement were obtained by recrystallization with the mixed solvent of methanol and dimethyl formamide (v/v=5:1) at room temperature. The crystal is monoclinic, space group P 2(1)/ c with crystal parameters of a =0.7116(1) nm, b =0.8735(2) nm, c =1.3160(3) nm, β =101.12(2)°, V =0.8026(3) nm 3 , d calc. =1.450 g/cm 3 , Z =4, F (000)=368. The theoretical study on the title compound as a structure unit was carried out at HF/6-31+G(d), MP2/6-31+G(d) and B3LYP/6-31+G(d) levels. The population analysis and the stability have been discussed. The melting enthalpy (Δ H m ) and melting entropy (Δ S m ) of the title compound are 14.94±0.51 kJ mol −1 and 32.37 J K −1 mol −1 , respectively, and the apparent activation energy and the pre-exponential constants of the exothermic decomposition reaction are 109.84 kJ mol −1 and 10 9.41 s −1 , respectively.