[N(2)H(5)](+)(2)[N(4)C-N=N-CN(4)](2-): a new high-nitrogen high-energetic material

Energetic salts based on dipicrylamine and its amino derivative

Energetic salts based on dipicrylamine and its amino derivative were synthesized. All salts were fully characterized by multinuclear NMR spectroscopy ((1)H, (13)C), vibrational spectroscopy (IR), and elemental analysis. Ethylenediammonium di-DPA (DPA=dipicrylamine) and 1,3-diaminoguanidinium DPA were further confirmed by single-crystal X-ray diffraction. These salts exhibit reasonable physical properties, such as high densities (1.71-1.81 g cm(-3)), good thermal stabilities (T(d) =155-285 °C), and low solubilities in water. The impact sensitivity of 1-methyl-3,4,5-triamino-1,2,4-triazolium DPA is lower than that of 2,4,6-trinitrotoluene (TNT), and for some other energetic salts their impact sensitivities are comparable to that of TNT. Based on experimental densities and theoretical calculations carried out by using the Gaussian 03 suite of programs, all the salts have calculated detonation pressures (22.5-27.8 GPa) and velocities (7226-7917 m s(-1)) that exceed those of conventional TNT. The toxicities of these salts measured by luminescent bacteria toxicity tests are much lower than that of TNT, and two binary eutectic mixtures with melting points that fall between 70 and 100 °C were identified.

Comparative theoretical studies of energetic azo s-triazines

In this work, the properties of the synthesized high-nitrogen compounds 4,4',6,6'-tetra(azido)azo-1,3,5-triazine (TAAT) and 4,4',6,6'-tetra(azido)hydrazo-1,3,5-triazine (TAHT), and a set of designed bridged triazines with similar bridges were studied theoretically to facilitate further developments for the molecules of interests. The gas-phase heats of formation were predicted based on the isodesmic reactions by using the DFT-B3LYP/AUG-cc-PVDZ method. The estimates of the condensed-phase heats of formation and heats of sublimation were estimated in the framework of the Politzer approach. Calculation results show that the method gives a good estimation for enthalpies, in comparison with available experimental data for TAAT and TAHT. The crystal density has been computed using molecular packing calculations. The calculated detonation velocities and detonation pressures indicate that -NF(2), -NO(2), -N═N-, and -N═N(O)- groups are effective structural units for improving the detonation performance of the bridged triazines. The synthesized TAAT and TAHT are not preferred energetic materials due to their inferior detonation performance. The p→π conjugation effect between the triazine rings and bridges makes the molecule stable as a whole. The electrostatic behavior of the bridged triazines is characterized by an anomalous surface potential imbalance when incorporating the strongly electron-withdrawing -NF(2) and -NO(2) groups into the molecule. An analysis of the bond dissociation energies shows that all these derivatives have good thermal stability over RDX and HMX, and the -NH-NH- bridge is more helpful for improving the stability than -N═N(O)- and -N═N- bridges. Considering the detonation performance and thermal stability, three bridged triazines may be considered as the potential candidates of high-energy density materials (HEDMs).

Poly[μ-(5,5'-diazenediylditetra-zolido)-dicaesium]

The asymmetric unit of the title compound, [Cs(2)(C(2)N(10))](n), comprises a Cs(+) cation, and one-half of a 5,5'-diazenediylditetra-zolide anion. The Cs(+) cation is six-coordinated by N atoms from six 5,5'-diazenediylditetra-zolide ligands. Each 5,5'-diazenediylditetra-zolide ligand is surrounded by 12 Cs(+) cations, coordinating through ten N atoms. The Cs(+) cations are arranged in a chain along the a-axis direction with a Cs⋯Cs separation of 4.4393 (10) Å. Such coordination leads to the formation of the three-dimensional framework.

Quantum-chemical studies on hexaazaisowurtzitanes

Highly nitrated cage molecules constitute a new class of energetic materials that have received a substantial amount of interest. Among them 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) is a powerful explosive with poor impact and friction characteristics. In the present study we aim to design novel energetic materials by tailoring the molecular structure of CL-20. Important characteristics such as the heat of formation and density have been predicted using density functional theory and packing calculations, respectively. Sensitivity correlations have been established for model compounds by analyzing the charge on the nitro groups. Molecules IDX1, IDX4, and IDX7 have been found to have comparable performance with better insensitivity characteristics and may be explored as CL-20 substitutes in defense applications.

Energetic nitrogen-rich Cu(II) and Cd(II) 5,5'-azobis(tetrazolate) complexes

Copper(II) and cadmium(II) complexes of 5,5'-azobis(tetrazolate) (ABT) were synthesized at ambient temperature. The anhydrous copper(II) and cadmium(II) salts (1) and (3) are very impact sensitive. The energetic copper(II) and cadmium(II) ABT coordination complexes, tetraammine copper 5,5'-azobis(tetrazolate) dihydrate [Cu(NH(3))(4)]ABT(H(2)O)(2) (2) and diammine dihydrate cadmium 5,5'-azobis(tetrazolate) [Cd(NH(3))(2)(H(2)O)(2)]ABT (4) were prepared and then structured by single crystal X-ray diffraction. Their vibrational spectra (IR) were measured and compared with the calculated frequencies. Thermal stabilities were obtained from differential scanning calorimetry measurements and sensitivity toward impact was determined by BAM standards. The energies of combustion of 2 and 4 were based on oxygen bomb calorimetry values and were used to calculate the corresponding heats of formation.

Theoretical investigation on the heats of formation and the interactions among the isocyano groups in polyisocyanoprismanes C(6)H(6-n)(NC)(n) (n=1-6)

A series of polyisocyanoprismanes, C(6)H(6-n)(NC)(n) (n=1-6), has been designed computationally. We have calculated the heats of formation (HOFs) of the title compounds by using density functional theory (DFT) with 6-31G** basis set. We chose [3]prismane C(6)H(6)-D(3h) as a reference compound in the process of designing isodesmic reactions. The relationship between the HOFs and the molecular structures is discussed. The results have shown that the HOFs of the title compounds gradually increase with increasing number of isocyano groups. On average, the contribution of one isocyano group to the heat of formation is about 232.3 kJ/mol and 234.1 kJ/mol at the B3LYP and B3P86 levels, respectively. The relative stabilities of the title compounds are discussed in terms of the calculated HOFs, the energy gaps between the frontier orbitals, and the bond dissociation energies. The interactions of the isocyano groups in these polyisocyanoprismanes are also discussed. The results have not only shown that these compounds may be used as high-energy-density materials, but also provide some useful information for further syntheses.

Environmentally compatible next generation green energetic materials (GEMs)

This paper briefly reviews the literature work reported on the environmentally compatible green energetic materials (GEMs) for defence and space applications. Currently, great emphasis is laid in the field of high-energy materials (HEMs) to increase the environmental stewardship along with the deliverance of improved performance. This emphasis is especially strong in the areas of energetic materials, weapon development, processing, and disposal operations. Therefore, efforts are on to develop energetic materials systems under the broad concept of green energetic materials (GEMs) in different schools all over the globe. The GEMs program initiated globally by different schools addresses these challenges and establishes the framework for advances in energetic materials processing and production that promote compliance with environmental regulations. This review also briefs the principles of green chemistry pertaining to HEMs, followed by the work carried out globally on environmentally compatible green energetic materials and allied ingredients.

Energetic N,N,N',N'-tetraaminopiperazinium salts

The formation of terraminopiperazinium salts using water as solvent provides a green, straightforward approach to highly energetic salts that exhibit good thermal stabilities and moderate densities. The N,N,N',N'-tetraaminopiperazinium cation was selected for this study because of its high nitrogen-nitrogen bond content and its hign positive near or formation. Theoretical and empirical calculations on energetic salts based on this nitrogen-rich cation reveal them to have high positive molar enthalpies of formation, as high as 1034.0 kJ mol(-1), supporting the application of these new salts as potential energetic materials.