This paper presents the synthesis of novel high nitrogen molecular complexes based on 1,2,4,5-tetrazine derivatives and 4,4′,5,5′-tetranitro-2,2′-diimidazole (TNBI). Experimental and computational studies of the energy contribution of various components of co-crystals to the thermal stability of TNBI have been carried out. The thermal stability of molecular complexes was evaluated using differential scanning calorimetry and thermogravimetric analysis, and their energetic characteristics were calculated. A comprehensive analysis of the thermal analysis curves and calculation of kinetic parameters for all stages of thermal decomposition were performed. The high thermal stability of the complexes up to 190°C is shown. The activation energy of various chemical reactions in the solid phase for the considered series of crystalline complexes varies from 179 to 306 kJ/mol. The reaction order during the initiation of decomposition with a thermal effect intensity of 10°C•min-1 ranged from 0.3 to 6.0.

This work describes the synthesis of molecular and molecular-ionic derivatives of azolo[1,2,4,5]tetrazines and 1,2,4,5-tetrazines containing amino and guanidino fragments. Experimental and computational studies on the contribution of various substituents (guanidine, nitroamine, 2,4,6-trinitroaniline, nitrate ions) into thermal stabilities of compounds, their activation energies and the mechanism of response to external thermal effects were carried out. The thermal stabilities of the compounds were evaluated by using the differential scanning calorimetry. In addition, their energetic characteristics were calculated. The kinetic parameters for the key step of thermal decomposition were calculated. High thermal stability values for compounds with amino groups and low stabilities for nitrates and N-nitro derivatives have been shown. The activation energy values in the series of compounds under consideration proved to be varied from 358 to 112 kJ mol-1, the reaction order from 3 to 6. The catalytic effects of the decomposition of the basic structural fragment for the introduced substituents were found to be from 23 to 232kJ mol-1.

Synthesis of the bis[1,2,4]triazolo[4,3- b :3,4- f ][1,2,4,5]tetrazines as well as a study of the basic optical, electrochemical and charge-transport properties of new compounds.

The treatment of tuberculosis is still a challenging process due to the widespread of pathogen strains resistant to antibacterial drugs, as well as the undesirable effects of anti-tuberculosis therapy. Hence, the development of safe and effective new anti-antitubercular agents, in addition to suitable nanocarrier systems, has become of utmost importance and necessity. Our research aims to develop liposomal vesicles that contain newly synthesized compounds with antimycobacterial action. The compound being studied is a derivative of imidazo-tetrazine named 3-(3,5-dimethylpyrazole-1-yl)-6-(isopropylthio) imidazo [1,2-b] [1,2,4,5] tetrazine compound. Several factors that affect liposomal characteristics were studied. The maximum encapsulation efficiency was 53.62 ± 0.09. The selected liposomal formulation T8* possessed a mean particle size of about 205.3 ± 3.94 nm with PDI 0.282, and zeta potential was + 36.37 ± 0.49 mv. The results of the in vitro release study indicated that the solubility of compound I was increased by its incorporation in liposomes. The free compound and liposomal preparation showed antimycobacterial activity against Mycobacterium tuberculosis H37Rv (ATCC 27294) at MIC value 0.94–1.88 μg/ml. We predict that the liposomes may be a good candidate for delivering new antitubercular drugs.

A study is performed of the photophysical properties of indolo[3,2-b]carbazole-based compounds synthesized earlier. The charge carrier mobility in the space charge-limited current mode and the energy levels of the highest occupied and lowest unoccupied molecular orbitals in the compounds are determined. It is shown that indolo[3,2-b]carbazole derivatives can be used as hole transporting layers in organic light-emitting diodes.

A series of novel [1,2,4]triazolo[1,5-b][1,2,4,5]tetrazines has been synthesized through oxidation reaction of the corresponding 3,6-disubstituted 1,2,4,5-tetrazines bearing amidine fragments. It is shown that the heterocyclic systems obtained can be modified easily at C(3) position in the reactions with aliphatic alcohols and amines. Also, the reactivity of [1,2,4]triazolo[1,5-b][1,2,4,5]tetrazines towards CH-active compounds has been studied. The obtained triazolo[1,5-b]annulated 1,2,4,5-tetrazines proved to be active in micromolar concentrations in vitro against filamentous anthropophilic and zooanthropophilic dermatophyte fungi (Trichophyton, Microsporum and Epidermofiton), which cause skin and its appendages (hair, nails) diseases.

This paper presents the data of research studies on the mechanisms, kinetics and thermodynamics of decomposition of three high-energy compounds: [1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine-3,6-diamine (TTDA), 3-amino-6-hydrazino[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine (TTGA) and 3,6-dinitroamino[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine (DNTT). The points of change of the reaction mechanisms under thermal effects with different intensities from 0.1 to 2000 s−1 have been established. The values of activation and induction energies for the limiting stages of decomposition have been obtained. The formation of nanostructured carbon nitride (α-C3N4) in condensed decomposition products, cyanogen (C2N2) and hydrogen cyanide (HCN) in gaseous products have been shown. Concentration-energy diagrams for the reaction products have been compiled. The parameters of heat resistance and thermal safety proved to be: 349.5 °C and 358.2 °C for TTDA; 190.3 °C and 198.0 °C for TTGA; 113.4 °C and 114.1 °C for DNTT. The energy and thermodynamic properties have also been estimated. This work found the activation energy of the decomposition process to be 129.0 kJ/mol for TTDA, 212.2 kJ/mol for TTGA and 292.2 kJ/mol for DNTT. The average induction energy of the catalytic process (Ecat) for TTGA was established to be 21 kJ/mol, and for DNTT-1500–1700 kJ/mol. The induction energy of the inhibition process (Eing) of TTDA was estimated to be 800–1400 kJ/mol.

5,11-Dihydroindolo[3,2-b]carbazoles were for the first time modified with acceptor 1,2,4,5-tetrazine fragments. The photophysical and charge-transport properties of the synthesized donor-acceptor heterocyclic systems were studied. It was shown that the introduction of the 1,2,4,5-tetrazine moieties makes it possible to increase the hole and electron mobility by one and two orders of magnitude, respectively, as compared to analogous 5,11-dihydroindolo-[3,2-b]carbazole derivatives studied previously.

A number of new 3-alkylthio-6-(3,5-dimethylpyrazol-1-yl)[1,2,4]triazolo[4,3-b][1,2,4,5]-tetrazines were synthesized and modified in nucleophilic substitution reactions with aliphatic amines. The study of the tuberculostatic activity of the compounds obtained revealed a number of active derivatives with a minimum inhibitory concentration of 0.37–3.1 µg mL−1.

Tuberculosis (TB) has recently become the leading killer among infectious diseases. Multidrug and extensively drug-resistant Mycobacterium tuberculosis strains urge the need to develop anti-TB drugs with a novel mechanism of action. We describe synthesis of 22 novel imidazo[1,2-b][1,2,4,5]tetrazine derivatives with different substituents at C(3) and C(6) positions, and their antimycobacterial activity in vitro. 8 compounds show activity as potential serine/threonine protein kinase (STPK) inhibitors in M. smegmatis aphVIII+ test-system, which is characteristic for this class. 3 compounds out of 5 most active STPK inhibitors have a prominent minimal inhibitory concentration on M. tuberculosis H37Rv of 1 μg/ml. We were able to obtain M. smegmatis mc2 155 mutants resistant to 4 compounds and show that they do not have cross resistance with other drugs, but have a common mechanism of resistance among these 4 imidazo[1,2-b][1,2,4,5]tetrazines. Compound 3h seems the most promising, combining a predicted STPK inhibitor activity, the lowest MIC on M. tuberculosis and a low frequency of drug resistant mutants' emergence.

2-Substituted 5-aryltetrazoles containing alkyl and aminoalkyl fragments were synthesized using alkylation and Mannich reactions. The tuberculostatic activity of the synthesized compounds against strain M. tuberculosis H37Rv was studied. Pronounced tuberculostatic activity (MIC ≤ 1.5 ìg/mL) was found for tetrazoles containing N(2) dimethyl- and diethylaminoethyl fragments.

A series of novel 3-substituted 7-phenylimidazo[1,2-b][1,2,4,5]tetrazines was synthesized via the reaction of 3-R-amino-1,2,4,5-tetrazines with 2-aminoacetophenone. The structural features and possibilities of modification of 7-phenylimidazotetrazine system in the reactions with nucleophiles were studied.

A number of new 3-substituted imidazo[1,2-b][1,2,4,5]tetrazines containing azolyl, aminopyridyl, and alkoxyl substituents was synthesized. These compounds were studied for the biological activity against mycelial anthropophilic and zoophilous dermatophyte fungi (Trichophyton, Microsporum and Epidermophyton), causing diseases of skin and its appendages (hair, nails), and yeast-like fungi Candida.

The structures and characteristic features of the molecular packing patterns of complexes of pyridazines containing heterocyclic substituents and the carborane moiety with 2,3,5,6-tetrachlorohydroquinone (TCHQ) were investigated. It was shown that TCHQ can form supramolecular assemblies with carborane-containing substituted pyridazines. The stoichiometry and three-dimensional structures of these assemblies depend on the substituents in the pyridazine ring and are formed via O-H…N hydrogen bonding between TCHQ and heterocyclic molecules.

Derivatives of s-tetrazine containing malonodinitrile, ethyl cyanoacetate, and 1,3-indanedione fragments were synthesized by the nucleophilic substitution of heterocyclic groups in 3,6-diazolyl-1,2,4,5-tetrazines. Coordination compounds of the cyanomethyltetrazine anion with Cu+, Mn2+, and the tetrathiafulvalene radical cation were obtained, and their structures were determined. A transformation of cyanomethyltetrazines to pyrrolo[1,2-b][1, 2, 4, 5]tetrazines catalyzed by metal cations was discovered.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.