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 an 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 H2 O2 in the presence of a catalyst, and insensitivity to impact, synthesized ionic liquids have strong application potential as energetic fuels for space technologies.

Design and Synthesis of Nitrogen-Rich Azo-Bridged Furoxanylazoles as High-Performance Energetic Materials.

A series of novel energetic materials comprising of azo-bridged furoxanylazoles enriched with energetic functionalities was designed and synthesized. These high-energy materials were thoroughly characterized by IR and multinuclear NMR (1 H, 13 C, 14 N) spectroscopy, high-resolution mass spectrometry, elemental analysis, and differential scanning calorimetry (DSC). The molecular structures of representative amino and azo oxadiazole assemblies were additionally confirmed by single-crystal X-ray diffraction and X-ray powder diffraction. A comparison of contributions of explosophoric moieties into the density of energetic materials revealed that furoxan and 1,2,4-oxadiazole rings are the densest motifs while the substitution of the azide and amino fragments on the nitro and azo ones leads to an increase of the density. Azo bridged energetic materials have high nitrogen-oxygen contents (68.8-76.9 %) and high thermal stability. The synthesized compounds exhibit good experimental densities (1.62-1.88 g cm-3 ), very high enthalpies of formation (846-1720 kJ mol-1 ), and, as a result, excellent detonation performance (detonation velocities 7.66-9.09 km s-1 and detonation pressures 25.0-37.7 GPa). From the application perspective, the detonation parameters of azo oxadiazole assemblies exceed those of the benchmark explosive RDX, while a combination of high detonation performance and acceptable friction sensitivity of azo(1,2,4-triazolylfuroxan) make it a promising potential alternative to PETN.

Synthesis and Evaluation of the (S)-BINAM Derivatives as Fluorescent Enantioselective Detectors.

Pd(0)-catalyzed amination was employed for the synthesis of a new family of (S)-1,1'-bianaphthalene-2,2'-diamine derivatives possessing additional chiral and fluorophore substituents. The compounds thus obtained were tested as potential detectors of seven amino alcohols, and some of them were found to be able to recognize individual enantiomers of certain amino alcohols by specific changes of their emission spectra in the presence of these analytes. A pronounced dependence of the detecting abilities on the nature of the substituents in the (S)-BINAM derivatives was observed.