• Zhang Xian-Zhou

      Articles written in Journal of Chemical Sciences

    • The solvent and substituent effects on bond dissociation energies of NO-donor molecules containing the N-NO bond

      Li Xiao-Hong Li Wei-Bin Zhang Xian-Zhou

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      Quantum chemical calculations are used to estimate the equilibrium N-NO bond dissociation energies (BDEs) for 15 NO-donor molecules in acetonitrile. These compounds are studied by employing the hybrid density functional theory (B3LYP, B3PW91, B3P86) methods together with 6-31G∗∗ basis set. The basis set superposition error (BSSE) and zero-point vibrational energy (ZPVE) are considered. The results are compared with the available experimental results. It is demonstrated that B3LYP/6-31G$^{\ast\ast}$ is accurate to compute the reliable BDEs for the NO-donor molecules. The solvent effects on the N-NO BDEs are analysed and the result shows that the N-NO BDEs in a vacuum computed by B3P86/6-31G∗∗ method are the closest to the computed values in acetontrile and the average solvent effect is 0.78 kcal/mol. Subsequently, the substituent effects on the N-NO BDEs are further analysed and it is found that electron donating group stabilizes the radical and as a result BDE decreases; whereas electron withdrawing group stabilizes the ground state of the molecule and thus increases the BDE.

    • Theoretical studies on a series of 1,2,4-triazoles derivatives as potential high energy density compounds

      Zhang Rui-Zhou Li Xiao-Hong Zhang Xian-Zhou

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      Density functional theory calculations at B3LYP/6-31G∗∗ and B3P86/6-31G∗∗ levels were performed to predict the densities (𝜌), detonation velocities (D), pressures (P) and the thermal stabilities for a series of 1,2,4-triazole derivatives for looking high energy density compounds (HEDCs). The heats of formation (HOFs) are also calculated via designed isodesmic reactions. The calculations on the bond dissociation energies (BDEs) indicate that the position of the subsitutent group has great effect on the BDE and the BDEs of the initial scission step are between 31 and 65 kcal/mol. In addition, the condensed phase heats of formation are also calculated for the title compounds. These results would provide basic information for further studies of HEDCs.

    • Theoretical investigation on crystal structure, detonation performance and thermal stability of a high density cage hexanitrohexaazaisowurtzitane derivative

      Li Xiao-Hong Cui Hong-Ling Li Li-Ben Zhang Xian-Zhou

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      Density functional theory calculations were performed to study the new polynitro cage compound with the similar framework of HNIW. IR spectrum, heat of formation and thermodynamic properties were predicted. The bond dissociation energies and bond orders for the weakest bonds were analysed to investigate the thermal stability of the title compound. The detonation and pressure were evaluated by using the Kamlet-Jacobs equations based on the theoretical density and condensed HOFs. In addition, the results show that there exists an essentially linear relationship between the WBIs of N-NO2 bonds and the charges -QNO2 on the nitro groups. The crystal structure obtained by molecular mechanics belongs to P21/C space group, with lattice parameters Z = 4, a = 12.3421 Å, b = 24.6849 Å, c = 20.4912 Å, 𝜌 = 1.896 g cm-3. The designed compound has high thermal stability and good detonation properties and is a promising high energy density compound.

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