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Predicted Crystal Structures, Analysis, Impact Sensitivities and Morphology of Solid High-Energy Complexes: Alkaline-Earth Carbohydrazide Perchlorates

Liu Y., Zhang R., Feng C.-G., Yang L., Zhang T.-L.

Central European Journal of Energetic Materials

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2015

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Vol. 12, no. 2

229--248

EN

The crystal structures, density of states, energy gap, thermodynamic properties, impact sensitivities and morphology of beryllium carbohydrazide perchlorate ([Be(CHZ)3](ClO4)2), magnesium carbohydrazide perchlorate ([Mg(CHZ)3](ClO4)2), calcium carbohydrazide perchlorate ([Ca(CHZ)3] (ClO4)2), strontium carbohydrazide perchlorate ([Sr(CHZ)3](ClO4)2) and barium carbohydrazide perchlorate ([Ba(CHZ)3](ClO4)2) were investigated using the density functional theory (DFT) and crystal morphology theory. The results show that all of the complexes have six-coordinated distorted octahedra, which is different from previous works. This was rationalised by consideration of the intermolecular interactions in the crystal structures. Hence the crystal structure is now more reliable. The chemical reactions of the whole molecule may be triggered by an electron transition of CHZ or ClO4 −. Furthermore the energy gaps were observed, and the values of the impact sensitivities were inferred to have the following sequence: [Be(CHZ)3](ClO4)2 > [Mg(CHZ)3](ClO4)2 > [Sr(CHZ)3](ClO4)2 > [Ca(CHZ)3](ClO4)2 > [Ba(CHZ)3](ClO4)2. In addition, the thermodynamic equations at 25-1000 K were obtained. The positive values of the standard molar free enthalpies shows that carbohydrazide perchlorates are stable at 298.15 K. The (1 0 -1) and (0 0 2) faces are the most important growth directions of the crystal morphologies, and have the minimum growth rates. From the cleaved main growth faces, it can be deduced that surface active agents with active hydrogen atoms in the functional groups could be used as crystal-control reagents to control the crystal morphology for alkaline-earth carbohydrazide perchlorates.

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Quantum Chemistry Studies on Bis(p-aminobenzoato)–lead(II) Complex [Pb(C6H4NH2COO)2]

Zhao P., Xu J., Li R., Zhang W., Cai Z.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 1

85-93

EN

The title complex, bis(p-aminobenzoato)–lead(II) [Pb(C6H4NH2COO)2], has been optimized at B3LYP/LANL2DZ level of theory and the calculated results show that the lead(II) ion adopts a four-coordinate geometry. The analyses of NPA and Mulliken atomic charge distributions indicate that during the process of the formation of this compound, both aminobenzoato ligands transfer their negative charges to the lead(II) ion. The lead atom and oxygen atoms form covalent bonds by using their 6p and 2p orbitals, respectively. The calculations of electronic spectra of the title complex show that there exist four absorption bands and the electronic transitions are mainly derived from the contributions ofboth an intraligand* transition and ligand-to-metal charge transfer (LMCT) transitions. The thermodynamic properties of the studied compound at different temperatures have been calculated and the corresponding relations between the properties and temperatures have also been obtained. The calculation of the second order optical nonlinearity has been carried out, and the molecular hyperpolarizability of the title complex is 7.61379x10–30 esu.

3

Experimental and Density Functional Studies on Two Substituted 1H-Benzimidazoles

Zhao P., Yu H., Jian F., Wang X.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 8

1511-1519

EN

Two substituted 1H-benzimidazoles, 2-(4-chlorophenyl)-1H-benzimidazole and 1-(2- chlorobenzyl)-2-(2-chlorophenyl)-1H-benzimidazole, have been synthesized and characterized by elemental analysis, IR and UV-Vis spectra. An extended MO calculations using density functional theory (DFT) at B3LYP/6-311G** level have been carried out on the two compounds. Comparison of the experiments with the calculated results suggests that the optimized geometries can well reproduce the molecular structures. Atomic charge distributions show that both of the title compounds are potential ligands to coordinate with metallic ions. Natural population analyses indicate that the electronic transitions corresponding to electronic spectra are mainly derived from the contribution of bands pi--pi*. Thermodynamic properties of the two title compounds at different temperatures have also been calculated on the basis of vibration analyses.

4

Crystal Structure, Infrared Spectra and Density Functional Theory Study on 2,3-Diketo-benzopiperazine Dimer

Zhao P., Jian F. F., Xiao H., Sun P.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 10

1935-1944

EN

2,3-Diketo-benzopiperazine, which exists as dimeric form in its crystal structure has been synthesized. The calculated results on the dimer at B3LYP/6-31G* level show that the average strength of the double hydrogen bonds is of medium-grade. Natural bond orbital analyses have been performed. The predicted harmonic vibration frequencies support the experimental values. The thermodynamic properties of the dimer at different temperatures have been calculated and the change of Gibbs free energy for the aggregation from the monomer to the dimerDelta GT = -30.86 kJ/mol at 298.15 K, which implies the spontaneous process of the dimer formation.