Investigation of Ethylenedinitramine as a Versatile Building Block in Energetic Salts, Cocrystals, and Coordination Compounds.

Abstract

Ethylenedinitramine (H2EDN, 1) was prepared in a simple manner and with a high overall yield by direct nitration of 2-imidazolidinone using 100% HNO3 at 0 °C and subsequent hydrolysis in water at 100 °C. The versatility of 1 allows its application as starting material for a broad range of different materials. It was used for the preparation of both various salts and cocrystalline materials incorporating varying amounts of the TATOT moiety. Furthermore, H2EDN was successfully applied in the concept of energetic coordination compounds (ECCs) resulting in five copper(II) and two silver(I) complexes. A reaction path for the direct precipitation or slow crystallization of 17 different salts, including several alkali, alkaline earth, silver, and nitrogen-rich samples, is presented. The substances were extensively characterized by low-temperature single-crystal X-ray diffraction, elemental analysis (EA), IR spectroscopy, differential thermal analysis (DTA), and thermogravimetric analysis (TGA), proving their high thermal stability, especially of the alkali salts. In addition, 1 and all salts were characterized by 1H, 13C, and 14N NMR, whereas 1 was also investigated using the beneficial 1H-15N HMBC NMR spectroscopy. The sensitivities toward various mechanical stimuli according to BAM standard methods, as well as ball drop impact and electrostatic discharge (ESD) were determined using the BAM 1-out-6 method. Hot plate and hot needle tests were performed, followed by further characterization of the copper(II)-based ECCs through laser ignition experiments and UV-vis spectroscopy, offering new candidates for nontoxic, less sensitive laser-ignitable materials. Several detonation parameters were calculated using EXPLO5 (V6.05.02).