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

Abstract

Dinitraminic acid (HN(NO 2 ) 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 lowtemperature 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. Further-more, 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 (H 2 O)](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.

Hybridization of Dinitramide and Dicyanamide: Evaluation of Nitrocyanamide in Energetic Salts and Coordination Compounds

“…Of the coordination modes shown in Figure , C is the only mode known to date, with two other modes described in the literature not observed as part of this work . For the structurally similar dinitramido ligand, a binding behavior via one of the oxygens is mainly known in copper complexes. , Recently, however, coordination via the nitramide nitrogen has also been observed by our group . For the equally similar dicyanamide anion, a wide variety of coordination modes have been discovered in copper complexes .…”

“…Furthermore, the use of 1-aminotetrazole, or 1,5-diaminotetrazole, which are known to form some of the best performing ECCs only resulted in decomposition. This behavior was already observed during the investigation of copper­(II) dinitramide ECCs and therefore most likely caused by an unwanted interaction with the nitramide moiety of the anion …”

“…Since the NCA – anion is the center piece between the dinitramide (DN – ) and the dicyanamide anions (DCA – ), it is expected that the complexes properties lie in between those of the two anions. In the best case, the poor solubility as well as the good sensitivity data of the DCA complexes are thus achieved together with the performance of the DN complexes. , …”

“…The latter point is particularly interesting with respect to the earlier work of our group about energetic complexes. Thus, the dicyanamide (DCA – ) and more recently the dinitramide anion (DN – ) have already been studied excessively in copper complexes. , The nitrocyanamide anion is therefore of particular interest in this context because of its structure. Since half of it consists of the oxidizing dinitramide anion due to its nitro group and the other half of the endothermic dicyanamide anion due to the nitrile unit.…”

“…, hydrazinium, hydroxylammonium), the concept of energetic coordination compounds offers further possibilities for adjusting the properties. In several studies, for example in copper dinitramide complexes, the thermal stability of the compounds has already been significantly increased by the introduction of bridging ligands …”