Home – Home – Jornals – Advanced Search

Binuclear [Pt(bt)m-(N^S)] ₂ complexes (bt ^- is the deprotonated form of 2-phenylbenzothiazole, (N^S) ^- = 2-mercaptopyridineate, 2-mercaptopyrimidineate, 2-mercaptobenzothiazoleate, 2-mercaptobenzoxazoleate ions) are characterized by the following methods: X-ray crystallography, ¹Н and ¹⁹⁵Pt NMR spectroscopy, electronic absorption and emission spectroscopy, cyclic voltammetry. The occurrence of the Pt-Pt chemical bond and complexes in both crystalline state and solution in the form of cis -N _(bt),S-binding isomers with the asymmetrical arrangement of two cyclometalated and two bridging ligands is shown. Long-wavе absorption bands and luminescence of the complexes in the red spectral range are due to spin-allowed and spin-forbidden optical charge transfer transitions from the metal-metal bond to the metalated ligand. In cyclic voltammetry, two-electron redox waves of the complexes are attributed to metal- and ligand-centered processes involving s* HOMO and p*(bt) LUMO of the complexes.

The possibility of modifying carbon materials by RCVD and MOCVD of complex high-melting coatings consisting of the inner hafnium carbide layer and the outer iridium layer is studied. The morphological features, microstructure, and phase composition of the carbide and complex HfC-Ir coating on a carbon material are examined by scanning electron microscopy and powder X-ray diffraction analysis. The HfC coating is uniform, continuous, repeating the geometry of a carbon substrate. A scheme of chemical reactions describing the processes of hafnium transfer on carbon in the form of gaseous hafnium fluorides with a lower valence is proposed. The iridium coating consists of slightly elongated crystallites and has a good adhesion to the carbide layer.

The structure of two new ionic compounds of sparfloxacin (C ₁₉H ₂₂F ₂N ₄O ₃, SfH), SfH ₃[ZnCl ₄]×1.5H ₂O (I) and SfH ₃[CdBr ₄]×H ₂O (II), is determined. Crystallographic data are as follows: for I a = 14.505(3) Å, b = 12.615(3) Å, c = 29.118(7) Å, V = 5254(4)Å ³, space group Pbca , Z = 8; for II a = 13.2822(5) Å, b = 10.2564(4) Å, c = 21.3250(8) Å, b = 100.7248(4)°, V = 2854.3(3) Å ³, space group P 2 ₁/ n , Z = 4. The structures of the compounds are stabilized by intra- and intermolecular hydrogen bonds and the structure of I is additionally stabilized by the p-p interaction between the SfH ions.

Two new oxovanadium(V) complexes [VOL ¹(HQ)] (1) and [VOL ²(HQ)] (2) are prepared by the reaction of [VO(acac) ₂] (where acac = acetylacetonate), 8-hydroxyquinoline (HHQ) with 4-bromo- N'-(3-ethoxy-2-hydroxybenzylidene)benzohydrazide (H ₂L ¹) and 2-bromo- N'-(3-ethoxy-2-hydroxybenzylidene)benzohydrazide (H ₂L ²), respectively, in methanol. Crystal and molecular structures of the complexes are determined by elemental analysis, infrared spectroscopy, and single crystal X-ray diffraction. Complex 1 crystallizes in the monoclinic space group P 2 ₁/ c , with unit cell dimensions a = 12.5236(13) Å, b = 22.5260(15) Å, c = 16.7029(13) Å, b = 90.054(2)°, V = 4712.0(7) Å ³, Z = 8, GOOF = 1.024, R ₁ = 0.0586 and wR ₂ = 0.0835. Complex 2 crystallizes in the triclinic space group P -1, with unit cell dimensions a = 7.4344(12) Å, b = 10.8677(16) Å, c = 14.687(2) Å, α = 85.327(5)°, β = 77.357(5)°, γ = 84.896(5)°, V = 1150.9(3) Å ³, Z = 2, GOOF = 1.153, R ₁ = 0.0917 and wR ₂ = 0.3014. The V atoms are in the octahedral coordination. Thermal stability of the complexes is also studied.

Reaction of the morpholine amide derivative of 2-phenyl-4-quinolinecarboxylic acid with mercury(II) acetate and lithium chloride results in chloromercuration at the ortho position on the phenyl ring; the complex was characterised by ESI mass spectrometry and an X-ray structure determination.

The molecular structure of 3-oxo-urs-12-en-28-oic acid anhydride is determined. Crystals of C ₆₀H ₉₀O ₅ compound (III) are monoclinic, space group С2, at 100 K a = 15.1308(13) Å, b = 23.5150(19) Å, c = 15.1275(12) Å, β = 108.276(2)°. Molecules in the crystal are located in a special position on axis 2.

Structures of different classes of organic crystal hydrates are considered and their structural classification is presented based on the dimensionality and planarity of the included (Н ₂О) _n motif (water associate). The structural data are generalized with respect to the proton excess of the water associate.

A crystallographic analysis of the highly symmetrical cubic structure of Sc _0,8B _9,64C _0,53Si _0,057 is conducted of both centers of the [B ₁₂] and [B ₁₀] cluster groups with Sc and Si atoms and separately all individual atoms. In the first case, the analysis reveals an ordering with an I _cub sublattice ( а ≈ 5.1 Å) and a competing ordering with an F _cub sublattice ( а ≈ 6.8 Å). In the second case (for individual atoms), the analysis reveals orderings with analogous sublattices with twice as small parameters.

Methods of X-ray diffraction analysis and nuclear magnetic resonance are used to determine the molecular structure of macrobicyclic boron-capped tris -dioxymate iron(II) clathrochelate containing an annellated 5-membered heterocycle.

The inclusion compound of the composition [Zn ₂(dmf)(bdc)(lac)]×C ₅H ₆O is obtained by keeping a porous homochiral metal-organic polymer of the composition [Zn ₂(dmf)(bdc)(lac)]·DMF (DMF = N,N-dimethylformamide, H ₂bdc = terephthalic acid, H ₂lac = S -lactic acid) in liquid 2-cyclopentene-1-one, and the crystal structure of the compound is determined.