Dinitramide Anion Research Articles

Replacement of Toxic Hydrazines in Satellite Propulsion with Greener Dinitramide-Based Energetic Ionic Liquid Candidates.

Satellite propulsion uses liquid mono or bi-propellants composed of a hydrazine in combination with a strong oxidant. However, hydrazines are highly toxic. As a result, many research efforts for more environmentally compatible propellants have been made over the past decade. In this study we evidence green formulations that retain high propulsive performances. They are based on the dinitramide anion. From an initial library of 37 ammonium dinitramides 3 best candidates were selected after evaluation of their potential syntheses, calculated theoretical performances, experimental synthesis optimizations and decomposition temperatures. These three salts were then formulated to obtain acceptable sensitivities and melting points, which eventually led to only one formulation being retained: a 40 : 60 mixture of dimethylammonium dinitramide and ammonium dinitramide phlegmatized by 10 % of glycerol.

First Example of 1,2,5-Oxadiazole-Based Hypergolic Ionic Liquids: a New Class of Potential Energetic Fuels.

The development of liquid energetic fuels with improved properties is important topic in space propulsion technologies. In this manuscript, a series of energetic ionic liquids incorporating a 1,2,5-oxadiazole ring and nitrate, dicyanamide or dinitramide anion was synthesized and their physicochemical properties were evaluated. The synthesized compounds were fully characterized and were found to have good thermal stabilities (up to 219 °C) and experimental densities (1.21-1.47 g cm-3). Advantageously, 1,2,5-oxadiazole-based ionic liquids have high combined nitrogen-oxygen contents (up to 64.4%), while their detonation velocities are on the level of known explosive TNT, and combustion performance exceeds those of benchmark 2-hydroxyethylhydrazinium nitrate. Considering the established hypergolicity with H2O2 in the presence of a catalyst, and insensitivity to impact, synthesized ionic liquids have strong application potential as energetic fuels for space technologies.

A Smart Access to the Dinitramide Anion - The Use of Dinitraminic Acid for the Preparation of Nitrogen-Rich Energetic Copper(II) Complexes.

Dinitraminic acid (HN(NO2)2, HDN) was prepared by ion exchange chromatography and acid‐base reaction with basic copper(II) carbonate allowed the in situ preparation of copper(II) dinitramide, which was reacted with twelve nitrogen‐rich ligands, for example, 4‐amino‐1,2,4‐triazole, 1‐methyl‐5H‐tetrazole, di(5H‐tetrazolyl)‐methane/‐ethane/‐propane/‐butane. Nine of the complexes were investigated by low‐temperature X‐ray diffraction. In addition, all compounds were investigated by infrared spectroscopy (IR), differential thermal analysis (DTA), elemental analysis (EA) and thermogravimetric analysis (TGA) for selected compounds. Furthermore, investigations of the materials were carried out regarding their sensitivity toward impact (IS), friction (FS), ball drop impact (BDIS) and electrostatic discharge (ESD). In addition, hot plate and hot needle tests were performed. Complex [Cu(AMT)4(H2O)](DN)2, based on 1‐amino‐5‐methyltetrazole (AMT), is most outstanding for its detonative behavior and thus also capable of initiating PETN in classical initiation experiments. Laser ignition experiments at a wavelength of 915 nm were performed for all substances and solid‐state UV‐Vis spectra were recorded to apprehend the ignition mechanism.

Synthesis Optimization of Guanidinium Dinitramide (GDN).

Dinitramide anion [-N(NO₂)₂] salt composed of resonance structure is a plausible oxidizing agents, as efficient propellant. Among them, guanidinium dinitramide (GDN) is an organic compound improving the stability against moisture, as well long term storage. An additional advantage composed guanidinium ion is the reaction efficient via the decomposed by-product during pyrognostics, maximum yield of 99%. The types of GDN (GDN-I, II, III, IV, V) were synthesized using several starting material such as guanidine acetate, chloride, carbonate, nitrate and sulfate under hydrodeprivation. In this work, the intermediates formed in these processes were closely identified and their thermal properties, and chemical structure were examined. The absorption peaks by Fourier transform infrared (FT-IR) were found guanidinium infrared frequencies (3452, 3402, 3354, 3278, 1642 cm-1) and dinitramide infrared frequencies (3208, 1570, 1492, 1416, 1337, 1179, 1000 cm-1). The activation energy of GDN samples were obtained Ea = 53.26 Kcal/mole (GDN-I), 50.94 Kcal/mole (GDN-II), 52.34 Kcal/mole (GDN-III), 62.19 Kcal/mole (GDN-IV), 55.32 Kcal/mole (GDN-V) from exothermic at over 153°C.

Synthesis, Characterization, and Thermal Decomposition of a New Energetic Salt 3-Amino-1,2,4-Triazole Dinitramide

ABSTRACTA new energetic salt, 3-amino-1,2,4-triazole dinitramide (ATADN), was synthesized through the combination of 3-amino-1,2,4-triazole cation and oxygen-rich dinitramide anion. The structure of ATADN was confirmed by single-crystal X-ray diffraction, elemental analysis, Fourier transform infrared spectroscopy, ultraviolet–visible spectrometry, and nuclear magnetic resonance spectroscopy. The thermal stability of ATADN was studied using differential scanning calorimetry, thermogravimetric analysis (TG), and TG tandem infrared spectrum. The thermal decomposition kinetics parameter was also calculated using the differential thermal analysis data based on Kissinger’s method. Results indicated that ATADN exhibited resistance to thermal decompositions of up to 439 K, and a corresponding activation energy of Ea = 281.9 kJ·mol−1. Moreover, its mechanical sensitivity and detonation properties were evaluated, which showed promising results for its potential application as a highly explosive compound.

Synthesis and characterization of fluorodinitroamine, FN(NO2)2.

NF3 and N(NO2)3 are known compounds, whereas the mixed fluoronitroamines, FN(NO2)2 and F2NNO2, have been unknown thus far. One of these, FN(NO2)2, has now been prepared and characterized by multinuclear NMR and Raman spectroscopy. FN(NO2)2 is the first known example of an inorganic fluoronitroamine. It is a thermally unstable, highly energetic material formed by the fluorination of the dinitramide anion using NF4(+) salts as the preferred fluorinating agent.

Synthesis and Characterization of Fluorodinitroamine, FN(NO2)2

AbstractNF3 and N(NO2)3 are known compounds, whereas the mixed fluoronitroamines, FN(NO2)2 and F2NNO2, have been unknown thus far. One of these, FN(NO2)2, has now been prepared and characterized by multinuclear NMR and Raman spectroscopy. FN(NO2)2 is the first known example of an inorganic fluoronitroamine. It is a thermally unstable, highly energetic material formed by the fluorination of the dinitramide anion using NF4+ salts as the preferred fluorinating agent.

Polyamino-Substituted Guanyl-Triazole Dinitramide Salts with Extensive Hydrogen Bonding: Synthesis and Properties as New Energetic Materials

A series of new energetic salts based on the polyamino-1-guanyl-triazole cation with three to five amino groups and the dinitramide anion were synthesized. These new nitrogen-rich salts tend to have extensive hydrogen bonding and exhibit high densities and thermal stabilities. The impact of multiple amino groups in the cation of the dinitramide salts was investigated. Their properties were modified by varying the guanyl substituents and/or the amino substituents on the triazole ring. On the basis of theoretical calculations, 3,5-diamino-1-guanyl-1,2,4-triazole dinitramide, 8, has higher detonation pressure and velocity values than the dinitramide energetic materials such as ammonium dinitramide (ADN), and N-guanylurea-dinitramide (FOX-12). The structures of salts 7−10 (where 7 is 3-amino-1-guanyl-1,2,4-triazole dinitramide, 8 is 3,5-diamino-1-guanyl-1,2,4-triazole dinitramide, 9 is 5-amino-N-amidino-1-guanyl-1,2,4-triazole dinitramide, and 10 is 3,5-diamino-N-amidino-1-guanyl-1,2,4-triazole dinitramide) were investigated using single-crystal X-ray diffraction analysis.

Oxygenversusnitrogen interactions in lithium dinitramidate dihydrate and pyridinium dinitramidate

The title compounds, diaquadinitramidatolithium(I), [Li(N3O4)(H2O)2], (I), and pyridinium dinitramidate, C5H6N+ x N3O4(-), (II), differ significantly in their cation-anion contacts. The Li+ atom of (I) is coordinated by two O atoms of the dinitramide anion in a chelate and by four additional water molecules, with the Li and central N atom of the anion on a twofold rotation axis. The pyridinium cation of (II) exhibits a contact with the dinitramide anion via an intermolecular N-H...N hydrogen bridge. These interactions are compared with those found in reported anhydrous lithium dinitramide and ammonium dinitramide salts.

Triazolium-Based Energetic Ionic Liquids

The energetic ionic liquids formed by the 1,2,4-triazolium cation family and dinitramide anion are investigated by ab initio quantum chemistry calculations, to address the following questions: How does substitution at the triazolium ring's nitrogen atoms affect its heat of formation, and its charge delocalization? What kind of ion dimer structures might exist? And, do deprotonation reactions occur, as a possible first step in the decomposition of these materials?

Characterizing the oxygen-oxygen interaction in the dinitramide anion.

Atomic interactions between oxygen atoms have been analyzed in terms of the Theory of Atoms in Molecules for the biguanidium dinitramide and biguanidium bis-dinitramide crystals. The electron density has been derived from X-ray diffraction data obtained at 90 K, and the potential energy density has been calculated using the density functional approach. Bond critical points have been found on the O(1)...O(4) interatomic line in both the electron density and potential energy density gradient fields. The bond path and its associated virial path have been obtained. The interaction has been identified as a bonding closed-shell type interaction.

On the structure and spectra of dinitramide salts

The preparation for the isotopically substituted dinitramide salts has been proposed. The 14N and 15N NMR spectra of the 15N-enriched dinitramide anion in solution are measured and interpreted for the first time. New experimental IR and Raman spectra are obtained for the NH4+ and K+ salts of dinitramide in the solid state and in solution. The assignments are made with the help of quantum-mechanical force field calculations and normal-coordinate analysis. The harmonic vibrational spectrum of the dinitramide anion calculated at the B3LYP/6-31+G(d) level in the presence of solvent correlates best with the experimental data. The structure and spectra of the M+CH(NO2)2− and M+N(NO2)2− (M denotes a counterion) are compared and discussed. Topology of the electron charge density in the dinitramide anion is analyzed within the framework of Bader's theory of atoms in molecules.

ChemInform Abstract: Dinitramide Anion as a Reagent for the Controlled Replacement of Fluorine by Oxygen in Halogen Fluorides.

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Dinitramide anion as a reagent for the controlled replacement of fluorine by oxygen in halogen fluorides

The reactions of KN(NO 2) 2 with BrF 5, CIF 5 and IF 7 were investigated. It is shown that the N(NO) 2) 2 anion is superior to NO 3 as a reagent for the controlled, stepwise replacement of two ligands by a doubly bonded oxygen atom. Thus, KN(NO 2) 2 readily reacts with BrF 5 at −45°C to give KBrOF 4, N 2O and FNO 2 in quantitative yield. With CIF 5 at −13°C, an equimolar mixture of KCIOF 4 and KCIF 4 was obtained. The formation of KCIOF 4 is remarkable because with most fluorine-oxygen exchange reagents, such as NO 3, the exchange process cannot be arrested at the CIOF 4 stage and yields FCIO 2 as the only product. In the case of IF 7, deoxygenation of the desired IOF 6 − product occurred resulting instead in the formation of KIF 6 which, in the presence of excess IF 2, formed the novel KIF 6·2IF 7 adduct.

A new class of flexible energetic salts, part 2: The crystal structures of the cubane-1,4-diammonium dinitramide and cubane-1,2,4,7-tetraammonium dinitramide salts

The crystal structures of cubane-1,4-diammonium dinitramide, 1, and cubane-1,2,4,7-tetraammonium dinitramide, 2, have been determined. 1 crystallizes in the space group P21/c with cell dimensions a = 6.018(2), b = 11.642(3), c = 9.754(3) A, β = 107.24(2), while 2 crystallizes in the space group P21/c with cell dimensions a = 9.401(4), b = 9.603(3), c = 12.603(4) A, β 111.08(3). In these structures the ammonium substituents are symmetrically attached with respect to the cubane skeleton and have neither low lying empty orbitals nor available lone pairs of electrons thus they have a minimal effect on the metrical parameters of the cubane skeleton. All C–C bond lengths are close to the overall average C–C bond length for all reported cubanes of 1.559 A. The conformations adopted by the dinitramide ions in both structures are quite different, with the bend, twist, and torsion angles for the dinitramide ion in 1 being significantly larger than those found for the dinitramide ions in 2, due to the different types of hydrogen bonding found in the two structures. In 2, the conformation adopted by the adjacent ammonium ions allows two of the three protons from each ammonium cation to form hydrogen bonds in such a manner that they span either the syn or the anti oxygen atoms of a single dinitramide anion. The dinitramide anion is thus constrained by these interactions and is less free to twist and bend. These results provide further confirmation that the metrical parameters of both the cubane and dinitramide moieties are flexible and reflect their local environment.

A new class of flexible energetic salts, part 4 : The crystal structures of hexaaquomagnesium(II), hexaaquomanganese(II), and hexaaquozinc(II) dihydrate salts of dinitramide

The crystal structures of the hexaaquomagnesium (1), hexaaquomanganese (2), and hexaaquozinc (3) dihydrate salts of dinitramide have been determined. 1 crystallizes in the monoclinic space group P21/n with cell dimensions a = 9.589(2), b = 7.420(1), c = 11.116(2) A, β = 108.25(3)°, 2 crystallizes in the monoclinic space group P21/n with cell dimensions a = 9.623(4), b = 7.477(2), c = 11.274(3) A, β = 108.38(3)°, and 3 crystallizes in the monoclinic space group P21/n with cell dimensions a = 9.513(1), b = 7.4270(8), c = 11.164(1) A, β = 108.806(6)°. The three structures are isostructural, consisting of hexaaquo cations, dinitramide anions and water molecules interlinked by an extensive three dimensional hydrogen bonding interactions. All oxygen atoms as well as the central nitrogen atom of the dinitramide anion are involved in acceptor hydrogen bonds with neighboring water protons. As a consequence of the constraints imposed by these hydrogen bonds the dinitramide ions are almost planar with average deviations of 0.01 A for 1, 0.03 A for 2 and 0.03 A for 3.

1,1,3,3-Tetraoxo-1,2,3-triazapropene Anion, a New Oxy Anion of Nitrogen: The Dinitramide Anion and Its Salts

We report the synthesis of a completely new, stable class of inorganic salts named the dinitramide salts. These salts are based on a newly discovered nitrogen oxide anion known as the dinitramide anion. The dinitramide anion is a uniquely stable, high oxygen density grouping that can be prepared in many salt combinations including the ammonium or hydrazinium salts. The dinitramide anion has both fundamental scientific interest and practical applications. We describe here the synthesis of dinitramide salts and give a preliminary report on their properties.

Energetic Materials: The Preparation and Structural Characterization of Three Biguanidinium Dinitramides

Three biguanidinium salts of the energetic dinitramide anion have been prepared and structurally characterized from room-temperature X-ray diffraction data. Biguanidinium mono-dinitramide, (BIGH)(DN), triclinic, P\overline 1, a = 4.3686 (4), b = 9.404 (2), c = 10.742 (1) Å, \alpha = 83.54 (1), \beta = 80.386 (9), \gamma = 79.93 (1)°, V = 426.8 (1) Å3, Z = 2, D x = 1.62 g cm−3. Biguanidinium bis-dinitramide, (BIGH2)(DN)2, monoclinic, C2/c, a = 11.892 (2), b = 8.131 (1), c = 13.038 (2) Å, \beta = 115.79 (1)°, V = 1135.1 (3) Å3, Z = 4, D x = 1.84 g cm−3. Biguanidinium bis-dinitramide monohydrate, (BIGH2)(DN)2.H2O, orthorhombic, P212121, a = 6.4201 (6), b = 13.408 (1), c = 14.584 (2) Å, V = 1255.4 (4) Å3, Z = 4, D x = 1.76 g cm−3. All three structures are characterized by extensive hydrogen bonding. Both the mono- and diprotontated cations consist of two planar halves twisted with respect to each other. The dinitramide anion has a surprisingly variable and asymmetric structure. The two halves of the anion are twisted with respect to each other; however, the twist varies from 5.1 to 28.9°. In addition, the two ends of the anion have significantly different geometries, e.g. the `equivalent' N—N bond lengths differ by up to 0.045 Å.

Dinitramide and its salts

The dinitramide anion shows ambident properties. Its reactions with alkylating reagents give rise to N- or O-alkylated products or their mixtures. The reactions of alkylated products with bases were studied.

Density functional study of the structure and some decomposition reactions of the dinitramide anion N(NO 2) 2−

We have used a non-local density functional procedure (DF/GGA/DZVPP) to compute the structure of the dinitramide anion N(NO 2) 2 − and the energetics of some possible decomposition steps. The structures are in good agreement with crystallographic results, and show the NO 2 groups to be rotated out of the N-N-N plane, with a considerable difference between the two N-N-O angles of each NO 2 group. Of three possible N-N bond breaking reactions, we find that the least energy is required to yield NNO 2 − and NO 2 (49.8 kcal mol −). We suggest that these products have the option of forming a loosely bound complex.