In search of the most thermally stable 1,1,1-trinitrocompounds, several well-known and new energetic 1,2,4,5-tetrazines have been synthesized. The thermal stability of obtained compounds has been investigated by the methods of isothermal and non-isothermal kinetics. The introduction of the OCH2 or NHCH2 bridge between the heterocycle and the trinitromethyl moiety has been confirmed to result in a significant increase in thermal stability. An increase in stability is accompanied by a decrease in the C–NO2 bond length by 0.025–0.029 Å. An additional increase in the thermal stability of 1.1,1-trinitro derivatives is possible due to the creation of high-melting compounds, the decomposition of which proceeds before melting. Trinitroethylamine derivatives are most preferred due to the strong hydrogen bonds of the NH group. However, in some cases, the actual stability of a substance is reduced by the appearance of autocatalysis. On the basis of experimental data of manometry, analysis of condensed decomposition products by HPLC and IR spectroscopy, a mechanism for the decomposition of 1,1,1-trinitrocompounds was proposed. The compounds studied were found to have favorable detonation properties, which were close to those of RDX, a commonly used explosive. At the same time, some of the obtained polynitro compounds have increased burning rates in comparison with the known nitramines HMX and RDX.

A method for the thermal cyclization of tetrazol-5-ylamino-1,2,4,5-tetrazine has been developed, leading to the formation of a new heterocyclic system based on 1,2,4-triazole and 1,2,4,5-tetrazine, a fused tricyclic compound, from which a number of other tricyclic derivatives containing nitramine, nitro, and keto groups have been obtained. Based on experimental studies and quantum-chemical calculations enthalpies of formation of the new fused energetic materials in the solid state have been found. The enthalpy of formation of the new fused tricyclic compound bis [1, 2,4] triazolo [1,5-b:5',1'-f] [1,2,4,5] tetrazine-2,7-diamine, DATC, (3505 kJ kg(-1)) exceeds the enthalpies of formation of diaminotetrazine (2652 kJ kg(-1)) and 5-aminotetrazole (2442 kJ kg(-1)), which makes the resulting framework one of the most energetic heterocyclic compounds. In addition, DATC and its derivatives turned out to be low-sensitive and thermally stable explosives, the stability of which is comparable to the known thermostable explosives TATB and TACOT, but with higher detonation characteristics. N,N'-(bis([1,2,4]triazolo) [1,5-b:5',1'-f] [1,2,4,5]tetrazine-2,7-diyl)dinitramide was used as a starting acid to obtain salts with organic bases. The hydroxylamine salt, H(2)DNATC, turned out to be the most powerful compound, comparable in detonation characteristics (D = 9020 m s(-1)) to HMX, but having a higher burning rate (54 mm s(-1) at 10 MPa), and therefore it may be of interest as a high-energy fast-burning filler for composite propellants and gunpowder. Thermocouple-aided studies in the H(2)DNATC combustion wave made it possible to estimate the enthalpy of dissociation of the salt into gaseous components and to establish the combustion mechanism. The demonstrated thermal cyclization method for the preparation of fused tricyclic tetrazines provides new insights into the design of HEDMs, which may be useful for practical applications.