A series of novel (NHC)PdCl₂-PR₃ complexes were synthesized and fully characterized by ¹H, ¹³C, ³¹P NMR and FT-IR spectroscopy. These complexes showed high catalytic activity toward solvent-free Buchwald–Hartwig amination. Both primary and secondary amines were efficiently utilized under the same reaction conditions. The solvent-free synthesis of valuable N-aryl carbazoles and similar N-heterocyclic systems was described.

High endothermicity is one of the most important factors in the design of high-performance energetic materials for a new generation of rocket technologies. Taking this into account, in this study, novel highly energetic cage compounds were synthesized by the incorporation of a high-enthalpy N-azidomethyl moiety into the polynitro hexaazaisowurtzitane backbone. All obtained compounds were fully characterized by high-resolution mass spectrometry, IR and multinuclear NMR (¹H, ¹³C, ¹⁴N, ¹⁵N) spectroscopy. For two of them, 4-azidomethyl-2,6,8,10,12-pentanitrohexaazaisowurtzitane and 4,10-bis(azidomethyl)-2,6,8,12-tetranitrohexaazaisowurtzitane, the density and structural features were established by X-ray diffractometry. Enthalpies of formation were determined experimentally by combustion calorimetry. Thermal stability measurements and testing of impact and friction sensitivity were also carried out. The synthesized compounds exhibit a high level of heat resistance (decomposition onset 180–205 °C) and density (1.85–1.93 g cm⁻³). Their enthalpies of formation on a unit of mass (up to 2210 kJ kg⁻¹) are the highest among the known hexaazaisowurtzitane derivatives and are 2–2.5 times that of CL-20. The combination of these attractive properties makes the new materials promising energetic components for propellant compositions.

A series of three different solvatomorphs of a new iron(II) complex with N,N′-disubstituted 2,6-bis(pyrazol-3-yl)pyridine, including those with the same lattice solvent, has been identified by X-ray diffraction under the same crystallization conditions with the metal ion trapped in the different spin states. A thermally induced switching between them, however, occurs in a solution, as unambiguously confirmed by the Evans technique and an analysis of paramagnetic chemical shifts, both based on variable-temperature NMR spectroscopy. The observed stabilization of the high-spin state by an electron-donating substituent contributes to the controversial results for the iron(II) complexes of 2,6-bis(pyrazol-3-yl)pyridines, preventing ‘molecular’ design of their spin-crossover activity; the synthesized complex being only the fourth of the spin-crossover (SCO)-active kind with an N,N′-disubstituted ligand.