Huisheng Huang

A screened hybrid density functional study on energetic complexes: cobalt, nickel and copper carbohydrazide perchlorates.

The molecular geometry, electronic structure, infrared spectra and thermochemical properties of cobalt and nickel tris(carbohydrazide) perchlorates (CoCP and NiCP) as well as copper bis(carbohydrazide) perchlorate (CuCP) were investigated using the Heyd-Scuseria-Ernzerhof (HSE) screened hybrid density functional. The results show that both perchlorate ions coordinate with the copper atom, and the interactions between copper and perchlorate are ionic, whereas all the metal-carbohydrazide interactions are covalent. Due to the delocalization from the sigma(N-H) bond orbital to the n*(M) antibond orbital, the amino stretching vibrations of these complexes show considerable red-shift compared with those of free carbohydrazide ligand. The calculated heats of reaction and formation indicate that the formations of these complexes are exothermic, and the order of their thermal stability is NiCP>CoCP>CuCP. These agree well with the experimental results. Finally, we find that there is a relationship between the energy gap and impact sensitivity.

Synthesis, structure, thermal behavior and energetic properties of a new 2D polymeric Ba(II) compound with tetrazole-1-acetic acid

A new energetic Ba(II) coordination polymer [Ba(tza)2]n (where tza = tetrazole-1-acetic acid anion) was synthesized and characterized by X-ray single crystal diffraction, elemental analysis and IR spectroscopy. In the molecule, the central Ba(II) cation was coordinated by eight carboxylic O atoms from six different tza ions. Quadridentate tza anion bridged three various Ba(II) atoms and formed a 2D supramolecular network. Differential scanning calorimetry (DSC) and thermogravimetric differential thermogravimetric (TG DTG) analyses were applied to assess the thermal decomposition behavior. The kinetic parameters were obtained by non-isothermal reaction kinetics, and the Arrhenius equation can be expressed as lnk = 22.47 – 291× 103/RT. Critical temperature of thermal explosion, thermodynamic parameters, energy of combustion, enthalpy of formation and sensitivities of [Ba(tza)2]n were measured or calculated to argue that as a potential energetic material.

Synthesis, crystal structure and thermal behavior of a new 1D polymeric strontium complex with tetrazole-1-acetic acid

A new 1D polymeric strontium compound (Sr(tza)2(H2O)2)n was synthesized by reaction of tetrazole-1-acetic acid (Htza) with strontium carbonate, and characterized by X-ray single crystal diffraction, elemental analysis and IR spectroscopy. The central Sr(II) atom is coordinated by eight O atoms from 4 tza − ions and two water molecules. A zigzag chain along the c-axis is constructed by the tridentate tza − anion bridging two Sr(II) atoms. Differential scanning calorimetry (DSC) and thermogravimetric-differential thermogravimetric (TG-DTG) analyses were applied to assess the thermal decomposition behav- ior. The kinetic parameters were obtained by non-isothermal reaction kinetics, and the Arrhenius equation can be expressed as lnk = 22.17-258.2 × 10 3 /RT. The critical temperature of thermal explosion values, �S / = , �H / = andG / = were obtained at 562 K as, −65.71 J mol −1 K −1 , 255.51 kJ mol −1 and 291.78 kJ mol −1 , respectively.

Theoretical Study for High Energy Density Compounds from Cyclophosphazene

The phosphazenes have distinguished ancestry. The reaction between phosphorus pentachloride and ammonia was described by Rose in 1834[1], and in an editorial comment, Liebig [13] reported work carried out in conjunction with Wohler. The major reaction product was phospham and a small quantity of a stable crystalline compound containing nitrogen, phosphorus, and chlorine was obtained. Gerhardt and Laurent established that the empirical composition was NPCl2, and Gladstone and Holmes and Wichelhaus measured the vapor density and deduced the molecular formula, N3P3Cl6[2].

First-principles study of energetic complexes (II): (5-cyanotetrazolato-N2) pentaammine cobalt (III) perchlorate (CP) and Ni, Fe and Zn analogues

AbstractFirst-principles methods using the TPSS density functional level of theory with the basis set 6-31G** were applied to study (5-cyanotetrazolato-N2) pentaammine cobalt (III) perchlorate (CP) and Ni, Fe and Zn analogues in the gas phase. The optimized lowest-energy geometry of CP was calculated from reported experimental structural data using the TPSS method. The calculated values are in good agreement with those measured by X-ray diffraction. Ni, Fe and Zn analogues were constructed and calculated on the same basis. NBO results showed that the metal-ligand interactions have covalent character. Donor-acceptor analyses predicted that the delocalization energy E2 decreases from Co to Zn, so the covalent nature of the complexes increases in the order Co>Fe>Ni>Zn. In addition, HOMO-LUMO composition was investigated to determine the stability of the title compounds. FigureFirst-principles methods employing the TPSS density functional level of theory with the basis sets 6-31G**, has been applied to study the (5-cyanotetrazolato-N2) pentaammine cobalt (III) perchlorate (CP) and its transition metal (Ni/Fe/ Zn) perchlorate analogues in the gas phase

Thermal stability improved by π-π stacking interactions: Synthesis, crystal structure and thermal decomposition of sodium nitroformate

An energetic salt, sodium nitroformate (NaNF), was synthesized and characterized by elemental analysis, IR and UV spectra, and its crystal structure was first determined by single crystal X-ray diffraction. The structure exhibits two types of π-π stacking interactions between the nitroformate anions, i e, the parallel-displaced and T-shaped configurations. Furthermore, the thermal decomposition mechanism was investigated by DSC, TG-DTG and FTIR techniques. The kinetic parameters of the thermal decomposition were also calculated by using Kissinger’s and Ozawa-Doyle’s methods. The results show that NaNF has a good thermal stability, which is attributed to the π-π stacking interactions.