The structural and vibrational properties of 6-(2-(2,4-dinitrophenylhydrazano)-tetrahydro-2thioxopyrimidin-4(1H)-one (3) prepared by condensation of synthesized thiobarbituric acid (1) with 2,4-dinitrophenylhydrazine (2) were studied using experimental FT-IR, FT-Raman, NMR spectra and theoretical calculations based on the density functional method were the simulated spectra coincides with exper...

Studies are reported of the upper critical fields of Nbo.53Tio.47-Ge multilayers consisting of thick Ge layers and varying-thickness Nbo.s3Tio.47 layers. Both the angular dependence and the temperature dependence of the upper critical fields indicate a dimensional crossover at a Nbo.s3Tio.47 layer thickness near 200 ~ . All the 2D samples display a cusplike upper critical field angular dependen...

We use ab initio pseudopotential total energy calculations with a plane wave basis set to investigate the structural energetics of various phases of polymorphic NbN. Particular attention is given to its recently discovered superconducting phase with a Tc of 16.4 K, reported to have the NbO structure type. Results of total energy calculations show that it is in fact energetically unfavorable for...

The reaction between niobium atom and acetaldehyde has been investigated with a DFT approach. Both ground and excited state potential energy surfaces are investigated in detail. The present results show that the title reaction starts with the formation of a η-CH3CHO-metal complex followed by C−C, aldehyde C−H, methyl C−H and C−O bond activation. These reactions can lead to several different pro...

Electron energy loss spectra in conjunction with near-edge fine structures of purely stoichiometric niobium monoxide (NbO) and niobium pentoxide (Nb2O5) reference materials were recorded. The structures of the niobium oxide reference materials were checked by selected area electron diffraction to ensure a proper assignment of the fine structures. NbO and Nb2O5 show clearly different energy loss...

Tetrel bond is analysed for a series of ZF4 (Z = C, Si, Ge) complexes with one and two NH3 or AsH3 ligands. The MP2/aug-cc-pVTZ calculations were performed and supported by results of the Quantum Theory of “Atoms in Molecules” (QTAIM) and the Natural Bond Orbitals (NBO) approaches. The Z-tetrel atoms of complexes analysed interact through their σ-holes with nitrogen or arsenic Lewis base centre...

The brain's anti-oxidant response to highly elevated oxygen (O2) partial pressures is poorly understood. In this study we hypothesized that hyperbaric O2 (HBO2) would stimulate superoxide dismutase (SOD) transcription in the oxidative stress-sensitive rat hippocampus and measured the time course and extent of the changes in hippocampal mRNA for all three SOD isoforms and total SOD enzyme activi...

The decomposition reaction of niobium(V) oxytrichloride ammoniate to the oxynitride of niobium in the 5+ oxidation state was developed in a methodological way. By combining elemental analysis, Rietveld refinements of X-ray and neutron diffraction data, SEM and TEM, the sample compound was identified as approximately 5 nm-diameter particles of NbO(1.3(1))N(0.7(1)) crystallizing with baddeleyite-...

A polyoxoniobate/g-C3N4 nanoporous material with functional groups has been synthesized by using carbon nitride (g-C3N4) and hexaniobate (K8Nb6O19·10H2O, abbreviated as NbO) as precursors. The structure and compositions of the as-prepared nanomaterials were characterized by XRD, FT-IR, FESEM, TEM, and XPS. These two kinds of materials interact with each other forming a hybrid composite, which c...