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.     

Nitration Products of 5‐Amino‐1H‐tetrazole and Methyl‐5‐amino‐1H‐tetrazoles – Structures and Properties of Promising Energetic Materials

The nitration of 5‐amino‐1H‐tetrazole ( 1 ), 5‐amino‐1‐methyl‐1H‐tetrazole ( 3 ), and 5‐amino‐2‐methyl‐2H‐tetrazole ( 4 ) with HNO₃ (100%) was undertaken, and the corresponding products 5‐(nitrimino)‐1H‐tetrazole ( 2 ), 1‐methyl‐5‐(nitrimino)‐1H‐tetrazole ( 5 ), and 2‐methyl‐5‐(nitramino)‐2H‐tetrazole ( 6 ) were characterized comprehensively using vibrational (IR and Raman) spectroscopy, multinuclear (¹H, ¹³C, ¹⁴N, and ¹⁵N) NMR spectroscopy, mass spectrometry, and elemental analysis. The molecular structures in the crystalline state were determined by single‐crystal X‐ray diffraction. The thermodynamic properties and thermal behavior were investigated by using differential scanning calorimetry (DSC), and the heats of formation were determined by bomb calorimetric measurements. Compounds 2, 5 , and 6 were all found to be endothermic compounds. The thermal decompositions were investigated by gas‐phase IR spectroscopy as well as DSC experiments. The heats of explosion, the detonation pressures, and velocities were calculated with the software EXPLO5, whereby the calculated values are similar to those of common explosives such as TNT and RDX. In addition, the sensitivities were tested by BAM methods (drophammer and friction) and correlated to the calculated electrostatic potentials. The explosion performance of 5 was investigated by Koenen steel sleeve test, whereby a higher explosion power compared to RDX was reached. Finally, the long‐term stabilities at higher temperatures were tested by thermal safety calorimetry (FlexyTSC). X‐Ray crystallography of monoclinic 2 and 6 , and orthorhombic 5 was performed.     

Insensitive and Thermostable Energetic Materials Based on 3‐Ureido‐4‐tetrazole‐furazan: Synthesis,Characterization, and Properties

Energetic salts composed of ureido, furazan, and tetrazole were prepared by simple and efficient chemical routes to explore new insensitive and thermostable energetic materials. 3‐Ureido‐4‐tetrazole‐furazan ( 3 ) and its ammonium salt ( 5 ) and hydrazinium salt ( 6 ) were confirmed by single‐crystal X‐ray diffraction. The thermal stabilities of the synthesized salts were studied using differential scanning calorimetry, and the detonation performances of these salts were calculated using EXPLO 5 V6.01. All the salts exhibit good thermal stability (Td: 148–259 °C) and mechanical sensitivities (IS > 40 J, FS > 360 N), and their detonation velocities range from 7316 to 8655 m · s^–1. Compounds 6 and 10 are potential candidates as novel insensitive and heat‐resistant explosives because of their high detonation temperatures of 247 and 256 °C, good detonation velocities of 8432 and 8523 m · s^–1, and good detonation pressures of 25.6 and 26.8 GPa.     

2‐(Dinitromethylene)‐1‐nitro‐1, 3‐diazacyclopentane‐Based Energetic Salts

Energetic salts that contain nitrogen‐rich cations and the 2‐(dinitromethyl)‐3‐nitro‐1, 3‐diazacyclopent‐1‐ene anion were synthesized in high yield by direct neutralization reactions. The resulting salts were fully characterized by multinuclear NMR spectroscopy (¹H and ¹³C), vibrational spectroscopy (IR), elemental analysis, density and differential scanning calorimetry (DSC), and elemental analysis. Additionally, the structures of the ammonium ( 1 ) and isopropylideneaminoguanidinium ( 9 ) 2‐(dinitromethyl)‐3‐nitro‐1, 3‐diazacyclopent‐l‐ene salts were confirmed by single‐crystal X‐ray diffraction. Solid‐state ¹⁵N NMR spectroscopy was used as an effective technique to further determine the structure of some of the products. The densities of the energetic salts paired with organic cations fell between 1.50 and 1.79 g · cm^–3 as measured by a gas pycnometer. Based on the measured densities and calculated heats of formation, detonation pressures and velocities were calculated using Explo 5.05 and found to to be 25.2–35.5 GPa and 7949–9004 m · s^–1, respectively, which make them competitive energetic materials.     

Brighter‐ and Longer‐Burning Barium‐Free Illuminants for Military and Civilian Pyrotechnics

The development of barium‐free pyrotechnic illuminants is described. Heavy metal barium nitrate oxidizer and strontium nitrate oxidizer were replaced with sodium nitrate to adequately address environmental concerns while providing the brightest possible illuminant. The new formulations further address environmental concerns and mitigate single‐point‐of‐failure through the replacement of polyester‐based Laminac 4116/Lupersol binder system with the epoxy‐based Epon 813/Versamid 140 binder system. The new formulations were found to burn longer and brighter than the control with a low sensitivity to various ignition stimuli.     

Energetic Materials Based on the 5‐Azido‐3‐nitro‐1, 2,4‐tri­azolate Anion

This study presents the preparation of 5‐azido‐3‐nitro‐1H‐1, 2,4‐triazole ( 1 ) in both good yield and high purity, starting from commercially available chemicals in a three step synthesis. Furthermore, several metal and nitrogen‐rich salts with sodium ( 3 ), potassium ( 4 ), cesium ( 5 ), silver ( 6 ), lead ( 7 ), ammonium ( 8 ), guanidinium ( 9 ), and aminoguanidinium ( 10 ) were prepared by simple acid‐base reactions. All compounds were well characterized by various means, including vibrational (IR, Raman) and multinuclear (¹H, ¹³C, ¹⁴N, ¹⁵N) NMR spectroscopy, mass spectrometry, and DSC. Additionally the structure of 7 was determined by single‐crystal X‐ray diffraction. The sensitivities towards various outer stimuli (impact, friction, electrostatic discharge) were determined according to BAM standards. The metal salts were tested as potential primary explosives utilizing various preliminary tests.     

New Substituted 1‐Aryl‐4,4,6‐Trimethyl‐3,4‐Dihydropyrimidine‐2‐(1H)Thiones; A Metal‐Free and Solvent‐Free Synthesis,Characterization, and Lymphoid Tyrosine Phosphatase Inhibition Studies

A series of fourteen 3,4‐dihydropyrimidine‐2‐thiones ( 3a–n ) were synthesized by a green protocol, and their structures were characterized by spectroanalytical data. The compounds were obtained in high yields by efficient annulation of mesityl oxide (4‐methylpent‐3‐en‐2‐one) with anilines in the presence of potassium thiocyanate. The reaction is essentially metal‐catalyst‐ and solvent‐free, as mesityl oxide itself is the solvent as well as the reactant. The compounds were tested for their ability to inhibit the lymphoid tyrosine phosphatase PTPN22, and 5 of the 14 compounds exhibited IC₅₀ values in the mid‐micromolar range, with the most potent hit being the compound 3d , having a methoxy substituent at the 2‐position of the phenyl ring with an IC₅₀ = 18 ± 1 μM, and second most potent compound ( 3c ) with an IC₅₀ value of 45 ± 3 μM, having methyl substituents at both 2‐ and 4‐position of the phenyl ring.     

Electrochemical Determination of a Free Chlorine Residual Using Cathodic Potential‐Step Chronocoulometry

The cathodic reaction of chlorine residual (CR) combined with anodic pre‐electrolysis enables the quantification of CR as a gaseous chlorine. Potential‐step chronocoulometry was successfully applied to extend the CR detection range.     

Two Energetic Salts based on 5,5′‐Bitetrazole‐1,1′‐diolate: Syntheses,Characterization, and Properties

Two salts based on 1H,1′H‐5,5′‐bitetrazole‐1,1′‐diolate (BTO) anion with pyrazole ( 1 ) and imidazole ( 2 ) cations were synthesized with metathesis reactions. Structural characterization was accomplished for them by using the element analysis, Fourier transform infrared spectroscopy (FT‐IR), NMR and mass spectrum, and X‐ray single crystal diffraction. Thermal analysis for the title salts were determined by means of differential scanning calorimetry (DSC) and thermogravimetry‐derivative thermogravimetry (TG‐DTG) as well as the calculation of non‐isothermal kinetic parameters. Consequently, both salts shown acceptable thermal stabilities as the decomposition temperatures were over 200 °C. The enthalpies of formation were calculated for these salts using the measured combustion energies with a result of 70.6 kJ · mol^–1 for 1 and –47.8 kJ · mol^–1 for 2 , respectively. Impact and friction sensitivities were also tested and the results indicated that these salts both have low sensitivities (>40 J, 120 N). The title energetic salts possess acceptable performance, they can therefore be applied in the field of energetic materials.     

Silver Salt and Derivatives of 5‐Azido‐1H‐1, 2, 4‐triazole‐3‐­carbonitrile

This study features the preparation of three new energetic C‐azido‐1, 2, 4‐triazoles, with the anion of one being a new binary C–N compound. 5‐Azido‐1H‐1, 2, 4‐triazole‐3‐carbonitrile ( 1 ) was prepared from 5‐amino‐1H‐1, 2, 4‐triazole‐3‐carbonitrile and further derivatized to 5‐azido‐1H‐1, 2, 4‐triazole‐3‐carbohydroximoyl chloride ( 5 ) with 3‐azido‐1H‐1, 2, 4‐triazole‐5‐carboxamidoxime ( 3 ) as an intermediate. The ability of 1 and 3 for salt formation was shown with the respective silver salts 2 and 4 . All compounds were well characterized by various means, including IR and multinuclear NMR spectroscopy, mass spectrometry, and DSC. The molecular structures of 1 , 3 , and 5 in the solid state were determined by single‐crystal X‐ray diffraction. The sensitivities towards various outer stimuli (impact, friction, electrostatic discharge) were determined according to BAM standards. The silver salts were additionally tested for their potential as primary explosives.     

The Reagent‐depending Nitration of 1,3‐Dihydroxyacetone Dimer

Two highly energetic nitric acid esters were synthesized from the dimer of dihydroxyacetone. 1,3‐Dinitratoacetone ( 1 ) and its dimer 2,5‐bis(nitratomethyl‐2,5‐nitrato)‐1,4‐dioxane ( 2 ) were characterized by single‐crystal X‐ray diffraction, vibrational spectroscopy (IR and Raman), multinuclear NMR spectroscopy, and elemental analysis. The thermal behavior was investigated with DTA measurements. Although showing the same atomic stoichiometry, dimer 2 shows significantly higher sensitivities measured by BAM methods (drophammer and friction tester). Due to the high oxygen content of 62.2 %, 1 and 2 were evaluated as potential high energy dense oxidizers.     

Syntheses,Crystal Structures,and Thermal Properties of Energetic Semicarbazide Salt,Manganese(II) Salt,and Coordination Compound of 3,5‐Dinitrobenzoic Acid

Nitro compounds have been actively researched as driven by their potential to be high‐performing energetic materials. Herein, three new nitro compounds including semicarbazide 3,5‐dinitrobenzoate, (SCZ)(DNBA), manganese 3,5‐dinitrobenzoate dihydrate, [Mn(DNBA)₂(H₂O)₂]_n, and bis(semicarbazide) manganese(II) 3,5‐dinitrobenzoate, Mn(SCZ)₂(DNBA)₂, were synthesized and characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction analysis. The results indicated that the above mentioned compounds are ionic, polymeric, and molecular in nature, respectively. Moreover, their thermal decomposition properties were assessed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Their non‐isothermal reaction kinetics parameters, critical temperature of thermal explosion (T_bp), entropy of activation (ΔS^≠), enthalpy of activation (ΔH^≠), and free energy of activation (ΔG^≠) of the exothermic decomposition process were also calculated. Results suggest that there was a relationship between the structure and thermal stability.     

Synthesis,Crystal Structure,and Properties of Energetic Copper(II) Complex based on 3,5‐Dinitrobenzoic Acid and 1,5‐Diaminotetrazole

Energetic copper(II) complexes based on 3,5‐dinitrobenzoic acid (HDNBA) and 1,5‐diaminotetrazole (DAT), Cu(DNBA)₂(H₂O)₂ ( 1 ) and Cu(DAT)₂(DNBA)₂ ( 2 ) were synthesized and characterized by elemental analysis, IR spectroscopy, single‐crystal and powder X‐ray diffraction. In both complexes, Cu^II was coordinated to a plane tetragon, by four oxygen atoms from two DNBA^– ions and two coordinated H₂O molecules for 1 , and by two oxygen atoms and two nitrogen atoms from different DNBA^– ions and DAT ligands for 2 . Differential scanning calorimetry (DSC) and thermogravimetry (TG) analyses were employed to measure the thermal decomposition processes and non‐isothermal kinetics parameters of the complexes. The thermal decomposition onset temperatures of 1 and 2 are 321 and 177 °C. The apparent activation energies of the first exothermic decomposition peaks of 1 and 2 are 247.2 and 185.2 kJ · mol^–1. Both 1 (35 J, > 360 N) and 2 (12.5 J, > 360 N) are less sensitive than RDX. The catalytic effects on the decomposition of ammonium perchlorate (AP) of 1 and 2 were studied by DSC. All results supported the potential applications of the energetic complexes as additives of solid rocket propellants.     

Energetic polymer salts from 1‐vinyl‐1,2,4‐triazole derivatives

Energetic polymers salts from 1‐vinyl‐1,2,4‐triazole derivatives have been synthesized via free radical polymerization of 1‐vinyl‐1,2,4‐triazolium monomer salts or by protonation of poly(1‐vinyl‐1,2,4‐triazole) with inorganic or organic acids. Standard enthalpies of formation of the new monomer salts were calculated using the computationally feasible DFT(B3LYP) and MP2 methods in conjunction with an empirical approach based on densities of salts. Compared with the monomer salts, the polymer salts have good thermal properties with high densities > 1.5 g cm^?3. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2414–2421, 2008     

Nitrogen‐Rich Alkali Metal Salts (Na and K) of [Bis(N,N‐bis(1H‐tetrazol‐5‐yl)amine)‐zinc(II)] Anion: Syntheses,Crystal Structures,and Energetic Properties

Two nitrogen‐rich alkali metal salts based on nitrogen‐rich anion [Zn(bta)₂]^2–: {[Na₂Zn(bta)₂(H₂O)₈] · H₂O}_n ( 1 ) and {[K₂Zn(bta)₂(H₂O)₄]}_n ( 2 ) were synthesized by reactions of alkali hydroxide, N,N‐bis(1H‐tetrazol‐5‐yl)amine (H₂bta), and zinc chloride in aqueous solutions. The crystal structures of 1 and 2 were determined by low temperature single‐crystal X‐ray diffraction and fully characterized by elemental analysis and FT‐IR spectroscopy. The structures demonstrate that an infinite 1‐dimensional (1D) chain structure is constructed by Na⁺ ions and bridging water molecules in compound 1 , which is connected by extensive hydrogen bonds forming a complex 3D network, whereas compound 2 features a more complicated 3D metal‐organic framework (MOF). The thermal behaviors of 1 and 2 were investigated by differential scanning calorimetry (DSC) measurements. The DSC results illustrate that both compounds exhibit high thermal stabilities (decomposition temperature > 345 °C). In addition, the heats of formation were calculated on the basis of the experimental constant‐volume energies of combustion measured by using bomb calorimetry. Lastly, the sensitivities towards impact and friction were assessed according to Bundesamt für Materialforschung (BAM) standard methods.     

Magnesium Azotetrazole‐1,1′‐dioxide: Synthesis and Promising Properties of Green Insensitive Energetic Materials

Magnesium azotetrazole‐1,1′‐dioxide ( 1 ) was first prepared and intensively characterized by single‐crystal X‐ray diffraction, IR spectroscopy, mass spectrometry, elemental analysis, and DSC measurements. The heat of formation was calculated using the atomization energy method based on quantum chemistry and the heat of detonation was also predicted. The NBO analysis was performed for inspecting charge distributions. The sensitivities towards impact and friction were tested using the BAM standard. The high detonation performance (5289 kJ · kg^–1), good thermal stabilities (245.5 °C) and excellent insensitivity (39.2 J and >360 N) as well as clean decomposition products supports it of great interest as a promising candidate of green insensitive energetic materials.     

Synthesis and Characteristics of Bis(2, 2‐dinitroethyl‐N‐nitro)ethylenediamine‐Based Energetic Salts

New energetic bis(2, 2‐dinitroethyl‐N‐nitro)ethylenediamine‐based salts exhibiting moderate physical properties, good detonation properties, and relatively low impact sensitivities were synthesized in high yield by direct reactions of bis(2, 2‐dinitroethyl‐N‐nitro)ethylenediamine with organic bases. The resulting salts were fully characterized by multinuclear NMR spectroscopy (¹H and ¹³C), vibrational spectroscopy (IR), differential scanning calorimetry (DSC), and elemental analysis. Solid‐state ¹⁵N NMR spectroscopy was used as an effective technique to further determine the structure of some products. Thermal decomposition kinetics and several thermodynamic parameters of some salts were obtained under non‐isothermal conditions by DSC. The densities of the energetic salts paired with organic cations were in the range 1.60–1.89 g · cm^–3 as measured with a gas pycnometer. Based on the measured densities and calculated heats of formation, detonation pressures and velocities were calculated using Explo 5.05 and found to be 23.6–44.8 GPa and 7790–9583 m · s^–1, respectively, which make them potentially useful as energetic materials.