The use of hypercrosslinked polymer sorbents and composites based on them in the sorption of toxic and bad-smelling substances

Russian Chemical Bulletin - The sorption of cadaverine from the air on hypercrosslinked polystyrene sorbents was investigated. An available technique for the introduction of iron oxide into the...     

Solvothermal Synthesis of the Metal-Organic Framework MOF-5 in Autoclaves Prepared by 3D Printing

Russian Journal of Coordination Chemistry - The known metal-organic framework {Zn4O(BDC)3} (MOF-5 (I), where BDC is terephthalate anion) is synthesized by the solvothermal method in autoclaves...     

Experimental Charge Density Evidence for Pnicogen Bonding in a Crystal of Ammonium Chloride

Chemical binding in crystalline ammonium chloride, a simple inorganic salt with an unexpectedly complex bonding pattern, was studied by using a topological analysis of electron density function derived from high‐resolution X‐ray diffraction. Supported by periodic quantum chemical calculations, it provided experimental evidence for weak σ‐hole bonds (1.5 kcal mol^?1) that involve ammonium cations in a crystal. Our results show this type of supramolecular interaction to be more numerous than has been found to date by using gas‐phase calculations or statistical analysis of CSD.     

Synthesis,structure, and stereochemical non-rigidity of bis[(2,2-dimethyl-4-oxo-2<Emphasis Type="Italic">H</Emphasis>-benzo[<Emphasis Type="Italic">e</Emphasis>][1,3]oxazin-3(4<Emphasis Type="Italic">H</Emphasis>)-yl)methyl] dichlorosilane and -germane

Bis[(2,2-dimethyl-4-oxo-2H-benzo[e][1,3]oxazin-3(4H)-yl)methyl]dichlorosilane (1) and -germane (2) were synthesized by the reaction of 2,2-dimethyl-3-(trimethylsilyl)-2H-benzo[e][1,3]oxazin-3(4H)-one with bis(chloromethyl)dichlorosilane and -germane, respectively, taken in a ratio of 2 : 1. The structures of these compounds were determined and their stereodynamic behavior in solution was studied by multinuclear (¹H, ¹³C, and ²⁹Si) and twodimensional (¹H, ¹³C COSY, HETCOR) NMR spectroscopy. The ²⁹Si NMR spectroscopic study of a solution of complex 1 provides evidence that the silicon atom in this complex is pentacoordinate. The X-ray diffraction study showed that the germanium atom in complex 2 in the solid state is hexacoordinate. The permutation isomerization in the coordination units of complexes 1 and 2 was found and investigated by dynamic ¹H NMR spectroscopy. Different mechanisms of stereodynamic transformations are suggested and discussed.     

The nature of chemical bonding in nitramide

The spatial and electronic structure studies of nitramide NH₂NO₂ suggest that the change in its molecular geometry upon transition from the gas phase to the condensed state is caused by an increase in the contribution of conjugation between functional groups. According to the analysis of the Bader atomic charges, the effects of such conjugation are to a considerable extent governed by intramolecular charge transfer from the amino to the nitro group. From estimation of the contribution of conjugation to the charge transfer it follows that conjugation remains in the isolated molecule. The influence of hydrogen bonding on the increase in the contribution of conjugation and the corresponding charge redistribution in the molecule was considered. Despite the presence of conjugation between functional groups, the planar configuration of the molecule in the crystal is not realized and the crystallographic twofold axis corresponds to superposition of two molecular configurations with C _s symmetry.     

Structural and functional diagnostics of ultrafine components in condensed high-energy systems

The study deals with octogen (HMX) and aluminum, which are among the most widely used components of condensed high-energy systems. The structure, thermal behavior and combustion parameters were determined for the octogen-based monofuels and octogen-aluminum binary systems at different dispersity of components. Irrespective of differences in thermal behavior, monofuels obtained with standard and ultrafine octogen powders were shown to have virtually identical combustion parameters. In the binary systems, replacement of standard microsized aluminum by ultrafine one increases the combustion rate by a factor of 2.5, and completeness of the metal reaction (oxidation) by a factor of 4.     

Synthesis and study of the structure of cage-like metallosiloxanes with pair combinations of 3d transition and alkaline earth metals

The selective replacement of Na ions in cage-like (Cu,Na) organosiloxanes in reactions with divalent metal halides was studied. The sandwich-like isomer [PhSiO₂]₆Cu₄Na₄[PhSiO₂]₆ forms the corresponding bimetallic complexes [PhSiO₂]₆Cu₄M₂[PhSiO₂]₆ (M = Cu, Zn, Mg, Sr, Ba) retaining a sandwich-like structure (in 60–90% yields) regardless of the metal ion size in MCl₂. Under similar conditions, the reactions of the globular isomers [RSiO₂]₁₂Cu₄Na₄ (R = Ph, Me, Vin) with CuX₂ (X = Cl or Br) afforded insoluble polymer products. The reaction in dioxane or THF in the presence of DMSO gave the crystalline globular-type metal complexes [RSiO₂]₁₂Cu₄[CuX]₄, in which Na ions are replaced by CuX groups. The compositions and structures of the synthesized metal complexes were studied by X-ray diffraction, elemental analysis, and destructive silylation combined with gel permeation chromatography and ¹H NMR spectroscopy.