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Eight alkaline and alkaline-earth compounds derived from 2,4-dinitroimidazole (2,4-HDNI) were synthesized and characterized by elemental analysis, FT-IR, and TG–DSC, of which K(2,4-DNI) (1), Rb(2,4-DNI)(2,4-HDNI)(H2O)2 (2), and Ba(2,4-DNI)2(H2O)4 (3) were characterized by single-crystal X-ray diffraction analysis. All the three compounds were crystallized from water, but 1 was an anhydrate. The coordination number in 1 and 3 is 10, but in 2 is 9. The 2,4-DNI adopts either η3, η2, or η1 coordination modes depending on the metal cation. In 3, there is an inversion center located on the metal. Only in 2 does water play an important role for the construction of the structure; in 3 it is a hydrogen bonding participant. TG–DSC analyses of 1 were also performed, and non-isothermal decomposition reaction kinetics were obtained.

Three neodymium compounds, Nd(4DNP)3(C2H5OH)3 (1), Nd(4DNPO)3 · 7H2O (2), and {[Nd(μ-ox)(4DNPO)(H2O)4] · 4H2O} n (3) (4HDNP, 3,5-dinitropyrid-4-one; 4HDNPO, 3,5-dinitropyrid-4-one-N-hydroxide; ox, oxalate), were synthesized and characterized by FT-IR, elemental analysis, thermogravimetry–differential scanning calorimetry (TG–DSC), and two of them by single-crystal X-ray diffraction analyses. The results revealed that in 1, the Nd(III) is surrounded by three chelating ligands and three ethanol solvent molecules. The structure of 3 could be described as 1-D chains in which Nd is bis-bidentately bridged by oxalates, together with a monodentate 3,5-dinitropyrid-4-onate N-oxide 4DNPO ligand and four water molecules as well as four uncoordinated water molecules in the crystal lattice. The origin of the oxalate anions in 3 is probably due to decomposition of the 4DNPO or its oxidation of other species. The TG–DTG (DTG, derivative thermogravimetry) and DSC analyses showed that 1 underwent a three-stage decomposit...

Three new energetic compounds, nickel(II) 3,5-dinitro-2-pyridonate (Ni(2DNPO)2(H2O)4, 1), copper(II) 3,5-dinitro-4-pyridonate (Cu(4DNPO)2(H2O)4, 2) and cobalt(II) 3,5-dinitro-4-pyridone-N-hydroxylate ([Co(4DNPOH)2(H2O)4] · 2DMF, 3 · 2DMF), were characterized by elemental analysis, FT–IR, TG-DSC and X-ray single crystal diffraction analysis. Complexes 1 and 2 are similar in structure with the metal ion coordinated by oxygen donors of four water molecules on the equatorial position and two nitrogen donors of the pyridone rings of two ligands in the axial positions. The cobalt(II) complex 3 · 2DMF is a heavily distorted octahedral geometry. The Co(II) has equatorial positions defined by oxygens of four water molecules. Its axial positions are filled with two oxygen atoms of the pyridone-N-hydroxylate of two ligands. The TG-DSC results reveal that 1 is the most stable, with higher initial thermal decomposition temperature and enthalpy. Based on the thermoanalyses, the nickel compound is a promising candidate ...

Six complexes, rubidium and cesium 3,5-dinitropyrid-2-onate (2DNPO), 3,5-dinitropyrid-4-onate (4NDPO), 3,5-dinitropyrid-4-one-N-hydroxylate (4DNPNO), were synthesized and characterized by elemental analysis, FT-IR, TG-DTG and X-ray single-crystal diffraction analysis. All the complexes crystallized from water and one of them was a hydrate. Rubidium 3,5-dinitropyrid-4-one-N-hydroxylate was crystallized with the 1 : 2 stoichiometry as Rb[H(4DNPNO)(2)] upon absorption of carbon dioxide. The structural determinations showed that the coordination sphere around a metal centre is made up of oxygen atoms and nitrogen atoms, except for the 4DNPNO complexes, where the coordination sphere accommodates exclusively oxygen atoms. The coordination numbers of the metal centers vary from 8, 10, 11 to 12, while the ligands, each employing its pyridone tautomer, link with metal cations. Bridging oxygen atoms play an important role in construction of two- and/or three-dimensional networks of these complexes. Hydrogen bonding contributes to the connectivity within a given sheet in Rb[H(4DNPNO)(2)]; aromatic - stacking interactions exist only in Cs(4DNPNO). The interactions between metal atoms and ligands are generally very weak. The organization of all layer structures appears to be governed mainly by steric effects and electrostatic forces with very little directional influence of the cations. The thermogravimetric analyses of these complexes showed the following consecutive processes: loss of NO(2) groups, collapse of the pyridyl ring backbones and finally inorganic residue formation. These complexes could be used as probes in template effects of heavy alkali-metal cations in the organization of biorelevant ligands and as environment-friendly energetic catalysts in solid propellants.