3,3′‐Diamino‐4,4′‐bifurazane (1), 3,3′‐diaminoazo‐4,4′‐furazane (2), and 3,3′‐diaminoazoxy‐4,4′‐furazane (3) were nitrated in 100 % HNO3 to give corresponding 3,3′‐dinitramino‐4,4′‐bifurazane (4), 3,3′‐dinitramino‐4,4′‐azofurazane (5) and 3,3′‐dinitramino‐4,4′‐azoxyfurazane (6), respectively. The neutral compounds show very imposing explosive performance but possess lower thermal stability and higher sensitivity than hexogen (RDX). More than 40 nitrogen‐rich compounds and metal salts were prepared. Most compounds were characterized by low‐temperature X‐ray diffraction, all of them by infrared and Raman spectroscopy, multinuclear NMR spectroscopy, elemental analysis, and by differential scanning calorimetry (DSC). Calculated energetic performances using the EXPLO5 code based on calculated (CBS‐4M) heats of formation and X‐ray densities support the high energetic performances of the nitraminofurazanes as energetic materials. The sensitivities towards impact, friction, and electrostatic discharge were also explored. Additionally the general toxicity of the anions against vibrio fischeri, representative for an aquatic microorganism, was determined.

Abstract1H,1′H‐5,5′‐Bitetrazole‐1,1′‐diol was synthesized starting from glyoxal, which is converted to glyoxime after treatment with hydroxylamine. Chlorination of glyoxime with Cl2 gas in ethanol and following chloro/azido exchange yields diazidoglyoxime, which is cyclized under acidic conditions (HCl gas in diethyl ether) to give 1H,1′H‐5,5′‐bitetrazole‐1,1′‐diol dihydrate (1). A large variety of nitrogen‐rich salts of 1 such as the diammonium (2), the dihydrazinium (3), the bis‐guanidinium (4), the bis(aminoguanidinium) (5), the diaminoguanidinium salt monohydrate (6), the triaminoguanidinium salt monohydrate (7), the 1‐amino‐3‐nitroguanidinium salt dihydrate (8), the diaminouronium salt monohydrate (9), the bis(oxalyldihydrazidinium) (10), the oxalyldihydrazidinium salt dihydrate (11), the 3,6‐dihydrazino‐1,2,4,5‐tetrazinium (12), the 5‐aminotetrazolium (13), the bis(5‐amino‐1‐methyl‐1H‐tetrazolium) salt (14), the bis(5‐amino‐2‐methyl‐2H‐tetrazole) adduct (15), and the 1,5‐diaminotetrazolium salt (16) were synthesized by means of Brønsted acid–base or metathesis reactions. All compounds were fully characterized by vibrational spectroscopy (IR and Raman), multinuclear NMR spectroscopy, elemental analysis, and differential scanning calorimetry (DSC) measurements. The crystal structures of 1–16 could be determined by using single‐crystal X‐ray diffraction. The heats of formation of 1–16 were calculated by using the atomization method on the basis of CBS‐4M enthalpies. With regard to their potential use as cyclotrimethylene trinitramine (RDX) or hexanitrostilbene (HNS) replacements, several detonation parameters such as the detonation pressure, detonation velocity, explosion energy, and explosion temperature were computed using the EXPLO5 code on the basis of the experimental (X‐ray) densities and calculated heats of formation. In addition, the sensitivities towards impact, friction, and electrical discharge were tested using the BAM drop hammer, a friction tester, as well as a small‐scale electrical discharge device.

In a crossed molecular beam experiment, the reactive scattering of sodium clusters Na n (n E 21) with water clusters (H 2 O) m (m E 40) is investigated. By measuring the angular and the velocity distributions of the scattered reaction products, direct information on the reaction mechanisms is obtained. The sodium clusters are generated in a supersonic expansion of sodium vapor from an oven with a refilling system with argon carrier gas. The products are detected by photoionization at wavelengths of 308 and 355 nm and mass analyzed in a time-of-flight mass spectrometer (TOF-MS). In addition, a fast chopper with a pseudorandom sequence modulating the sodium cluster beam allows us to determine at the same time the velocity distributions of the products. The scattering of Na clusters with H 2 O clusters shows only one series of reaction products, that is, solvated sodium atoms Na(H 2 O) m (m E 32) with maximum intensities at m ) 4, 5, 6. For all products, the measured angular and velocity distributions exhibit the formation of a complex that is stabilized by isotropic evaporation of water molecules. The detected products have low translational energy. Products containing NaOH have not been observed.

ARTICLE This journal isThe connection of highly endothermic heterocycles with high nitrogen but also oxygen content is a recent trend in the development of new energetic materials in order to increase densities and stabilities. Bis(1-hydroxytetrazolyl)furazane (9) and bis(1-hydroxytetrazolyl)furoxane (10) were synthesized for the first time from dicyanofurazane and dicyanofuroxane, respectively. Several nitrogen-rich (e.g. ammonium and hydroxylammonium) and metal salts thereof were prepared. Most compounds were characterized by single crystal X-ray diffraction. In addition all compounds were analyzed by vibrational spectroscopy (IR and Raman), multinuclear NMR spectroscopy, elemental analysis and DSC measurements. The heats of formation of 4, 5, 15-16, 20 and 24 were calculated using the atomization method based on CBS-4M enthalpies. With these values and the experimental (X-ray) densities several detonation parameters such as the detonation pressure, velocity, energy and temperature were computed using the EXPLO5 code (V.5.05). In addition, the sensitivities towards impact, friction and electrical discharge were tested using the BAM drop hammer and friction tester as well as a small scale electrical discharge device.

Sodium 5‐cyanotetrazolate sesquihydrate (1) was prepared from sodium azide and two equivalents of sodium cyanide under acidic conditions. Sodium 5‐cyanotetrazolate sesquihydrate (1) reacts with hydroxylammonium chloride to form 5‐aminohydroximoyl tetrazole (2). 5‐Aminohydroximoyl tetrazole (2) is treated with sodium nitrite and hydrochloric acid to form 5‐chlorohydroximoyl‐tetrazole (3). The chloride azide exchange yields 5‐azidohydroximoyl‐tetrazole monohydrate (4). When compound 4 is treated with hydrochloric acid, 5‐(1H‐tetrazolyl)‐1‐hydroxytetrazole (5) is obtained in good yield. Compound 5 can be deprotonated twice by various bases. Different ionic derivatives such as bis(hydroxylammonium) (6), bis(hydrazinium) (7), bis(guanidinium) (8), bis(aminoguanidinium) (9), bis(ammonium) (10), and diaminouronium (11) 5‐(1‐oxidotetrazolyl)‐tetrazolate were synthesized and characterized. With respect to energetic use salts 6 and 7 are most relevant. Compounds 3–9 and 11 were characterized using low temperature single‐crystal X‐ray diffraction. All compounds were investigated by NMR and vibrational (IR, Raman) spectroscopy, mass spectrometry and elemental analysis. The thermal properties were determined by differential scanning calorimetry (DSC). The sensitivities towards impact (4: 4 J, 5: 40 J, 6: 12 J, 7: 40 J), friction: (4: 60 N, 5: 240 N, 6: 216 N, 7: 240 N), and electrical discharge (5: 0.40 J, 6: 0.75 J, 7: 0.75 J), were investigated using BAM standards and a small scale electrostatic discharge tester. The detonation parameters of 5–7 were calculated using the EXPLO5.06 code and calculated (CBS‐4 M) enthalpy of formation values.