02016nas a2200133   4500008004100000245023100041210006900272260000800341300000900349490000800358520136800366100001301734856013501747       2017                        eng d00aDFT study on the effect of relative positions of methyl-, nitro- and N→oxide groups on the molecular structure, thermal/kinetic stability, crystal density, heat of decomposition and performance characteristics of triazolones0 aDFT study on the effect of relative positions of methyl nitro an  cAPR  a1-100 v1153 aMethyl-, nitro- and N→oxide substituted triazolones are of interest in the contest of high-energy density compounds and have been found to have true local energy minima at the B3LYP/aug-cc-pVDZ level. The optimised structures, harmonic frequencies and thermodynamic values for all the model molecules have been obtained in their ground state. The velocity of detonation (D) and detonation pressure (P) have been evaluated by the Kamlet–Jacob equations using the crystal density and the heat of explosion. The estimated performance properties are higher (D = 9.92–10.27 km/s, P = 48.10–52.52 GPa) compared with 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (D = 9.20 km/s, P = 42.0 Gpa). The higher densities are possibly due to the intramolecular hydrogen bonds and the layered structures in the crystal lattice. We speculate that the calculated heat of explosion and the density are for the gas phase compounds and in the reality they should be for the solid phase which would diminish the magnitude of the calculated values. The –N→O and –NO2 group leads to the desirable consequences of higher heat of explosion and diminished sensitivities. The substituting of N–H hydrogen atom(s) of triazolones for a –CH3 group decreases melting point, heat of formation and density; however, the methyl group increases the thermal stability.1 aRavi, P.  uhttps://library.ncl.res.in/content/dft-study-effect-relative-positions-methyl-nitro-and-n%E2%86%92oxide-groups-molecular-structure01760nas a2200145   4500008004100000022001300041245013800054210006900192260000800261300001000269490000900279520118900288100001301477856012401490       2017                        eng d  a2405830000aExperimental study and Ab-initio calculations on the molecular structure, infrared and Raman spectral properties of dinitroimidazoles0 aExperimental study and Abinitio calculations on the molecular st  cAUG  a11-230 v9-103 aThe structural and vibrational properties of 1,4-dinitroimidazole, 2,4-dinitroimidazole and 1-methyl-2,4-dinitroimidazole have been explored both experimentally and theoretically. The N1-N6, C2-NO2, C4-NO2, N1-CH3 lengths were found to be varied with the levels of theory and the calculated values were over estimated compared with those of experimental values. The experimental vibrational frequencies were compared with those values calculated at the HF/6–311 ++G(d,p), B3P86/6–311 ++G(d,p), B3LYP/6–311 ++G(d,p) and B3LYP/aug-cc-pVDZ levels. The calculated frequencies were in good agreement with the experimental values and the relative mean deviations between the measured and calculated vibrational frequencies were smaller than 1% for all molecules. The discrepancies in the bond lengths bond angles and harmonic frequencies are confined to the relative positions of NO2 groups that present a great deviation from the planarity of the molecule. Nevertheless the structural parameters and harmonic vibrational frequencies of nitroimidazoles calculated at the B3LYP/aug-cc-pVDZ level are superior compared with those values computed from other levels of calculation. 1 aRavi, P.  uhttps://library.ncl.res.in/content/experimental-study-and-ab-initio-calculations-molecular-structure-infrared-and-raman