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 (¹H, ¹³C, ¹⁴N) 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 of optically active 2,7-disubstituted naphthalene derivatives and evaluation of their enantioselective recognition ability

The palladium-catalyzed amination was used to synthesize 2,7-diamino derivatives of naphthalene containing two chiral substituents and fluorophore groups (dansyl, 7-methoxycoumarin, 6,7-dimethoxycoumarin, 6-aminoquinoline). The synthesized compounds were studied by UV absorption and fluorescence spectroscopy in the presence of individual enantiomers of amino alcohols and salts of 21 metals. The possibility of using these compounds as fluorescent detectors for optically active compounds and metals was examined. In the presence of (S)-leucinol, the diquinoline derivative showed enhanced emission with a maximum at shorter wavelengths, which is not typical of its (R) isomer. This fact can be used for the recognition of these enantiomers. A number of naphthalene derivatives can be considered as potential fluorescent chemosensors for Cu^II cations due to the total fluorescence quenching in the presence of this metal.

     

Synthesis of optically active 3,3’-disubstituted biphenyl derivatives using palladium-catalyzed amination and their evaluation as enantioselective fluorescent detectors for amino alcohols and metal cations

Russian Chemical Bulletin - The palladium-catalyzed amination was used to synthesize optically active 3,3’-diaminosubstituted biphenyl derivatives (in particular, macrocyclic derivatives)...