A Study of 5‐(1,2,4‐Triazol‐C‐yl)tetrazol‐1‐ols: Combining the Benefits of Different Heterocycles for the Design of Energetic Materials

The synthesis and full structural and spectroscopic characterization of three 5‐(1,2,4‐triazol‐C‐yl)tetrazol‐1‐ol compounds with selected energetic moieties including nitrimino ( 5 ), nitro ( 6 ) and azido ( 7 ) groups are reported. The influence of those energetic moieties as well as the C? C connection of a tetrazol‐1‐ol and a 1,2,4‐triazole on structural and energetic properties has been investigated. All compounds were well characterized by various means, including IR and multinuclear NMR spectroscopy, mass spectrometry, and DSC. The molecular structures of 5 – 8 were determined in the solid state by single‐crystal X‐ray diffraction. The standard heats of formation were calculated on the CBS‐4M level of theory utilizing the atomization energy method, revealing highly positive values for all compounds. The detonation parameters were calculated with the EXPLO5 program and compared to the common secondary explosive RDX. Additionally, sensitivities towards impact, friction and electrostatic discharge were determined.     

Gem‐dinitromethyl‐substituted Energetic Metal–Organic Framework based on 1,2,3‐Triazole from in situ Controllable Synthesis

Synthesizing energetic metal–organic frameworks at ambient temperature and pressure has been always a challenge in the research area of energetic materials. In this work, through in situ controllable synthesis, energetic metal–organic framework gem‐dinitromethyl‐substituted dipotassium 4,5‐bis(dinitromethyl)‐1,2,3‐triazole with a “cage‐like” crystal packing was obtained and characterized. Most importantly, for the first time, we found that it could be successfully afforded with a catalytic effect of trifluoroacetic acid. This new compound exhibited its high density (2.04 g cm^?3) at ambient temperature, superior detonation velocity (8715 m s^?1) to that of lead azide (5877 m s^?1) and comparable to that of RDX (8748 m s^?1). Its detonation products are mainly N₂ (48.1 %), suggesting it is also a green energetic material. The above‐mentioned performance indicates its potential applications in detonator devices as lead‐free primary explosive.     

Bis(4‐nitraminofurazanyl‐3‐azoxy)azofurazan and Derivatives: 1,2,5‐Oxadiazole Structures and High‐Performance Energetic Materials

Bis(4‐nitraminofurazanyl‐3‐azoxy)azofurazan ( 1 ) and ten of its energetic salts were prepared and fully characterized. Computational analysis based on isochemical shielding surface and trigger bond dissociation enthalpy provide a better understanding of the thermal stabilities for nitramine‐furazans. These energetic compounds exhibit good densities, high heats of formation, and excellent detonation velocity and pressure. Some representative compounds, for example, 1 (v_D: 9541 m s^?1; P: 40.5 GPa), and 4 (v_D: 9256 m s^?1; P: 38.0 GPa) exhibit excellent detonation performances, which are comparable with current high explosives such as RDX (v_D: 8724 m s^?1; P: 35.2 GPa) and HMX (v_D: 9059 m s^?1; P: 39.2 GPa).     

Nitroxy/Azido‐Functionalized Triazoles as Potential Energetic Plasticizers

The synthesis of a series of nitroxy‐ and azido‐functionalized compounds, based on 4‐amino‐3,5‐di(hydroxymethyl)‐1,2,4‐triazole, for possible use as an energetic plasticizers is described. All compounds were fully characterized. Two of them were further confirmed by X‐ray single crystal diffraction. Energetic performance was calculated by using EXPLO5 v6.01 based on calculated heats of formation (Gaussian 03) and experimentally determined densities at 25 °C. The results show that the nitration product 1‐nitro‐3,5‐di(nitroxymethyl)‐1,2,4‐triazole, containing a nitro group and two nitroxy groups, exhibits good detonation properties (D=8574 m s^?1, P=32.7 GPa). In addition, its low melting point makes it very attractive as an energetic plasticizer in solid propellants.     

Energetic Materials Based on 5,5′‐Diamino‐4,4′‐dinitramino‐3,3′‐bi‐1,2,4‐triazole

A simple and straightforward synthesis of 5,5′‐diamino‐4,4′‐dinitramino‐3,3′‐bi‐1,2,4‐triazole by the selective nitration of 4,4′,5,5′‐tetraamino‐3,3′‐bi‐1,2,4‐triazole is presented. The interaction of the amino and nitramino groups improves the energetic properties of this functionalized bitriazole. For a deeper investigation of these properties, various nitrogen‐rich derivatives were synthesized. The new compounds were investigated and characterized by spectroscopy (¹H and ¹³C NMR, IR, Raman), elemental analysis, mass spectrometry, differential thermal analysis (DTA), X‐ray analysis, and impact and friction sensitivities (IS, FS). X‐ray analyses were performed and deliver insight into structural characteristics with which the stability of the compounds can be explained. The standard enthalpies of formation were calculated for all compounds at the CBS‐4M level of theory, revealing highly positive heats of formation. The energetic performance of the new molecules was predicted with the EXPLO5 V6.02 computer. A small‐scale shock reactivity test (SSRT) and a toxicity test gave a first impression of the performance and toxicity of selective compounds.     

Study of Six Green Insensitive High Energetic Coordination Polymers Based on Alkali/Alkali‐Earth Metals and 4,5‐Bis(tetrazol‐5‐yl)‐2 H‐1,2,3‐triazole

Constructing insensitive high‐performance energetic coordination polymers (ECPs) with alkali/alkali‐earth metal ions and a nitrogen‐rich organic backbone has been proved to be a feasible strategy in this work. Six diverse dimensional novel ECPs (compounds 1 – 6 ) were successfully synthesized from Na^I, Cs^I, Ca^II, Sr^II, Ba^II ions and a nitrogen‐rich triheterocyclic 4,5‐bis(tetrazol‐5‐yl)‐2 H ‐1,2,3‐triazole (H₃BTT). All compounds show outstanding stability and low sensitivity, the thermal stability of these ECPs are significantly improved as the structural reinforcement increases from 1D to 3D, in which the decomposition temperature of 3D Ba^II based compound 6 is as high as 397 °C. Long‐term storage experiments show that compounds 5 and 6 are stable enough at high temperature. Moreover, the six compounds hold considerable detonation performances, in which Ca^II based compound 5 possesses the detonation velocity of 9.12 km s⁻¹, along with the detonation pressure of 34.51 GPa, exceeding those of most energetic coordination polymers. Burn tests further certify that the six compounds can be versatile pyrotechnics.     

Application of a 1‐benzyl‐4‐ferrocenyl‐1H‐[1,2,3]‐triazole/carbon nanotube modified glassy carbon electrode for voltammetric determination of hydrazine in water samples

The electrochemical behaviour of hydrazine at a 1‐benzyl‐4‐ferrocenyl‐1H‐[1,2,3]‐triazole‐triazole/carbon nanotube modified glassy carbon electrode has been studied. The modified electrode shows an excellent electrocatalytic activity for the oxidation of hydrazine and accelerates electron transfer rate. The electrocatalytic current increases linearly with hydrazine concentration in the range 0.5–700.0 μm and the detection limit for hydrazine was 33.0 ± 2.0 nm . The diffusion coefficient (D = 2.5 ± 0.1 × 10^?5 cm² s^?1) and kinetic parameters such as the electron transfer coefficient, (α = 0.52) and the heterogeneous rate constant (k′ = 5.5 ± 0.1 × 10^?3 cm s^?1) for hydrazine were determined using electrochemical approaches. Finally, the method was employed for the determination of hydrazine in water samples. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis of Amino,Azido, Nitro,and Nitrogen‐Rich Azole‐Substituted Derivatives of 1H‐Benzotriazole for High‐Energy Materials Applications

The amino, azido, nitro, and nitrogen‐rich azole substituted derivatives of 1H‐benzotriazole have been synthesized for energetic material applications. The synthesized compounds were fully characterized by ¹H and ¹³C NMR spectroscopy, IR, MS, and elemental analysis. 5‐Chloro‐4‐nitro‐1H‐benzo[1,2,3]triazole ( 2 ) and 5‐azido‐4,6‐dinitro‐1H‐benzo[1,2,3]triazole ( 7 ) crystallize in the Pca2₁ (orthorhombic) and P2₁/c (monoclinic) space group, respectively, as determined by single‐crystal X‐ray diffraction. Their densities are 1.71 and 1.77 g cm^?3, respectively. The calculated densities of the other compounds range between 1.61 and 1.98 g cm^?3. The detonation velocity (D) values calculated for these synthesized compounds range from 5.45 to 8.06 km s^?1, and the detonation pressure (P) ranges from 12.35 to 28 GPa.     

Nitrogen‐Rich Bis‐1,2,4‐triazoles—A Comparative Study of Structural and Energetic Properties

In this contribution, the synthesis and full structural and spectroscopic characterization of five bis‐1,2,4‐triazoles in combination with different energetic moieties like amino, nitro, nitrimino, azido, and dinitromethylene groups is presented. The main goal is a comparative study on the influence of those energetic moieties on the structural and energetic properties. A complete characterization including IR, Raman, and multinuclear NMR spectroscopy of all compounds is presented. Additionally, X‐ray crystallographic measurements were performed and deliver insight into structural characteristics as well as inter‐ and intramolecular interactions. The standard enthalpies of formation were calculated for all compounds at the CBS‐4M level of theory, the detonation parameters were calculated by using the EXPLO5.05 program. Additionally, the impact as well as the friction sensitivities and the sensitivity against electrostatic discharge were determined. The potential application of the synthesized compounds as energetic material will be studied and evaluated by using the experimentally obtained values for the thermal decomposition, the sensitivity data, and the calculated performance characteristics.     

Design and Synthesis of 2,5‐Disubstituted‐1,3,4‐Oxadiazole Hybrids Bearing Pyridine and 1,2,3‐Triazole Pharmacophores

A novel series of 2,5‐disubstituted‐1,3,4‐oxadiazoles decorated with two biodynamic moieties pyridine and 1,2,3‐triazole have been successfully synthesized in good yields under mild reaction conditions. The synthesized compounds are valuable for biological activity exploration since three biodynamic moieties are covalently linked together in a single molecular framework. All the synthesized compounds were fully characterized by their detailed spectral studies IR, ¹HNMR, ¹³C NMR and Mass.     

4‐Nitro‐3‐(5‐tetrazole)furoxan and Its Salts: Synthesis,Characterization, and Energetic Properties

A series of new energetic salts based on 4‐nitro‐3‐(5‐tetrazole)furoxan (HTNF) has been synthesized. All of the salts have been fully characterized by nuclear magnetic resonance (¹H and ¹³C), infrared (IR) spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). The crystal structures of neutral HTNF ( 3 ) and its ammonium ( 4 ) and N‐carbamoylguanidinium salts ( 9 ) have been determined by single‐crystal X‐ray diffraction analysis. The densities of 3 and its nine salts were found to range from 1.63 to 1.84 g cm^?3. Impact sensitivities have been determined by hammer tests, and the results ranged from 2 J (very sensitive) to >40 J (insensitive). Theoretical performance calculations (Gaussian 03 and EXPLO 5.05) provided detonation pressures and velocities for the ionic compounds 4 – 12 in the ranges 25.5–36.2 GPa and 7934–8919 m s^?1, respectively, which make them competitive energetic materials.     

Synthesis,Crystal Structure,and Thermal Behavior of a Novel Insensitive Energetic Cocrystal Composed of 3,3′‐Bis(1,2,4‐oxadiazole)‐5,5′‐dione and 4‐Amino‐1,2,4‐triazole

A novel insensitive energetic cocrystal consisting of 3,3′‐bis(1,2,4‐oxadiazole)‐5,5′‐dione and 4‐amino‐1,2,4‐triazole in a 1:2 molar ratio was prepared and characterized. The structure of this cocrystal was characterized by single‐crystal X‐ray diffraction. The crystal structure of the cocrystal is a monoclinic system with P1 space group. Properties of the cocrystal studied included thermal decomposition and detonation performance. This cocrystal has a crystal density of 1.689 g · cm^–3 at 173 K and good detonation performance (D = 6940 m · s^–1, P = 20.9 GPa). Moreover, measured impact and friction sensitivities (IS > 40 J, FS > 360 N) show that it can be classified as an insensitive energetic material. Its thermodynamic properties indicate that it has moderate thermal stability with a sharp exothermic peak (244 °C, 5 K · min^–1) and a high critical temperature of thermal explosion (523 K). In view of the observations above, it may serve as a promising alternative to known explosives such as TNT.     

Potassium 4,4′‐Bis(dinitromethyl)‐3,3′‐azofurazanate: A Highly Energetic 3D Metal–Organic Framework as a Promising Primary Explosive

Environmentally acceptable alternatives to toxic lead‐based primary explosives are becoming increasingly important for energetic materials. In this study, potassium 4,4′‐bis(dinitromethyl)‐3,3′‐azofurazanate, comprising two dinitromethyl groups and an azofurazan moiety, was synthesized and isolated as a new energetic 3D metal–organic framework (MOF). Several attractive properties, including a density of 2.039 g cm^?3, a decomposition temperature of 229 °C, a detonation velocity of 8138 m s^?1, a detonation pressure of 30.1 GPa, an impact sensitivity of 2 J, and friction sensitivity of 20 N make 4 a good candidate as a green primary explosive.     

Nitrogen‐Rich Energetic Monoanionic Salts of 3,4‐Bis(1 H‐5‐tetrazolyl)furoxan

3,4‐Bis(1H‐5‐tetrazolyl)furoxan (H₂BTF, 2 ) and its monoanionic salts that contain nitrogen‐rich cations were readily synthesized and fully characterized by multinuclear NMR (¹H, ¹³C) and IR spectroscopy, differential scanning calorimetry (DSC), and elemental analyses. Hydrazinium ( 3 ) and 4‐amino‐1,2,4‐triazolium ( 7 ) salts crystallized in the monoclinic space group P2(1)/n and have calculated densities of 1.820 and 1.764 g cm^?3, respectively. The densities of the energetic salts range between 1.63 and 1.79 g cm^?3, as measured by a gas pycnometer. Detonation pressures and detonation velocities were calculated to be 23.1–32.5 GPa and 7740–8790 m s^?1, respectively.     

Metal Salts of 3,3′‐Diamino‐4,4′‐dinitramino‐5,5′‐bi‐1,2,4‐triazole in Pyrotechnic Compositions

The synthesis of alkali and alkaline earth salts of 3,3′‐diamino‐4,4′‐dinitramino‐5,5′‐bi‐1,2,4‐triazole (H₂ANAT) is reported. The fast and convenient three steps reaction toward the target compounds does not require any organic solvents. In addition to an intensive characterization of all synthesized metal salts, the focus was on developing chlorine and nitrate‐free red‐light‐generating pyrotechnical formulations. Strontium 3,3′‐diamino‐4,4′‐dinitramino‐5,5′‐bitriazolate hexahydrate served as colorant and oxidizer in one molecule. The energetic properties of all developed pyrotechnical formulations assure safe handling and manufacturing.     

4,4′‐Butane‐1,4‐diylbis[3‐ethyl‐1H‐1,2,4‐triazol‐5(4H)‐one] and 4‐hydr­oxy‐3‐n‐prop­yl‐1H‐1,2,4‐triazol‐5(4H)‐one

The title compounds, C₁₂H₂₀N₆O₂, (I), and C₅H₉N₃O₂, (II), display the characteristic features of 1,2,4‐triazole derivatives. Compound (I) lies about an inversion centre which is at the mid‐point of the central C—C bond. Compound (II) also contains a planar 1,2,4‐triazole ring but differs from (I) in that it has a hydr­oxy group attached to the ring. Mol­ecules of (I) are held together in the crystal structure by inter­molecular N—H⋯O contacts and by weak π–π stacking inter­actions between the 1,2,4‐triazole moieties. Compound (II) contains inter­molecular O—H⋯O and N—H⋯O hydrogen bonds.     

Thermally Stable 3,6‐Dinitropyrazolo[4,3‐c]pyrazole‐based Energetic Materials

3,6‐Dinitropyrazolo[4,3‐c]pyrazole was prepared using an efficient modified process. With selected cations, ten nitrogen‐rich energetic salts and three metal salts were synthesized in high yield based on the 3,6‐dinitropyrazolo[4,3‐c]pyrazolate anion. These compounds were fully characterized by IR and multinuclear NMR spectroscopies, as well as elemental analyses. The structures of the neutral compounds 4 and its salt 16 were confirmed by single‐crystal X‐ray diffraction showing extensive hydrogen‐bonding interactions. The neutral pyrazole precursor and its salts are remarkably thermally stable. Based on the calculated heats of formation and measured densities, detonation pressures (22.5–35.4 GPa) and velocities (7948–9005 m s^?1) were determined, and they compare favorably with those of TNT and RDX. Their impact and friction sensitivities range from 12 to >40 J and 80 to 360 N, respectively. These properties make them competitive as insensitive and thermally stable high‐energy density materials.     

Combination of 1,2,4‐Oxadiazole and 1,2,5‐Oxadiazole Moieties for the Generation of High‐Performance Energetic Materials

Salts generated from linked 1,2,4‐oxadiazole/1,2,5‐oxadiazole precursors exhibit good to excellent thermal stability, density, and, in some cases, energetic performance. The design of these compounds was based on the assumption that by the combination of varying oxadiazole rings, it would be possible to profit from the positive aspects of each of the components. All of the new compounds were fully characterized by elemental analysis, IR spectroscopy, ¹H, ¹³C, and (in some cases) ¹⁵N NMR spectroscopy, and thermal analysis (DSC). The structures of 2 – 3 and 5 ‐ 1 ?5 H₂O were confirmed by single‐crystal X‐ray analysis. Theoretical performance calculations were carried out by using Gaussian 03 (Revision D.01). Compound 2 ‐ 3 , with its good density (1.85 g cm^?3), acceptable sensitivity (14 J, 160 N), and superior detonation pressure (37.4 GPa) and velocity (9046 m s^?1), exhibits performance properties superior to those of 1,3,5‐trinitroperhydro‐1,3,5‐triazine (RDX).     

Nitramines with Varying Sensitivities: Functionalized Dipyrazolyl‐ N‐nitromethanamines as Energetic Materials

1,3‐Dichloro‐2‐nitro‐2‐azapropane is an excellent precursor to dense energetic functionalized dipyrazolyl‐N‐nitromethanamines. This new family of energetic compounds was fully characterized by using ¹H, ¹³C, and ¹⁵N NMR and IR spectroscopy, differential scanning calorimetry, elemental analysis, and impact sensitivity tests. Additionally, single‐crystal X‐ray structuring was done for 3 and 5? CH₃CN, which gave insight into structural characteristics. The experimentally determined densities of 2 – 9 fall between 1.69 and 1.90 g cm^?3. Heats of formation and detonation properties were calculated by using Gaussian 03 and EXPLO5 programs, respectively. The influence of different energetic moieties on the structural and energetic properties was established theoretically.     

Potassium 1,1′‐Dinitramino‐5,5′‐bistetrazolate: A Primary Explosive with Fast Detonation and High Initiation Power

Adequate primary explosives such as lead azide mostly contain toxic ingredients, which have to be replaced. A new candidate that shows high potential, potassium 1,1′‐dinitramino‐5,5′‐bistetrazolate (K₂DNABT), was synthesized by a sophisticated synthetic procedure based on dimethylcarbonate and glyoxal. It was intensively characterized for its chemical (X‐ray diffraction, EA, NMR and vibrational spectroscopy) and physico‐chemical properties (sensitivity towards impact, friction, and electrostatic, DSC). The obtained primary explosive combines good thermal stability with the desired mechanical stability. Owing to its high heat of formation (326 kJ mol^?1) and density (2.11 g cm^?3), impressive values for its detonation velocity (8330 m s^?1) and pressure (311 kbar) were computed. Its superior calculated performance output was successfully confirmed and demonstrated by different convenient energetic test methods.