Formulation of perspective hepatoprotector polymeric forms based on silybin and ursodeoxycholic acid

Russian Chemical Bulletin - Silybin (Slb) and ursodeoxycholic acid (UDCA) are hepatoprotectors used in the pathogenetic therapy of liver and biliary tract. However, low bioavailability of these...     

Synthesis of a new aza-14-crown-4 with di(α-pyridyl)-substituted bispidine subunit and the crystal structure of its complex with CoCl2

The aza-14-crown-4 with the di(α-pyridyl)-substituted bispidine subunit (L) and its cationanion complex with cobalt(II) chloride of composition [Co(L)(H₂O)][CoCl₄] (I) have been synthesized. The structure of compound L has been proved by IR spectroscopy, NMR, and mass spectrometry. X-ray crystallography has demonstrated that the L molecule in the complex is an NNNN-tetradentate chelating ligand, and the crown ether moiety is not directly bound to the metal cation. In the cationic moiety of the complex, the Co(1) atom has an octahedral environment, and the Co(2) polyhedron in the anionic moiety is a tetrahedron. The cationic and anionic moieties of complex I are linked by the bridging chlorine atom.     

Influence of configuration interaction on splitting of multiplets of TmF<Stack><Subscript>6</Subscript><Superscript>3−</Superscript></Stack> and TmCl<Stack><Subscript>6</Subscript><Superscript>3−</Superscript></Stack> molecular complexes

The Stark structure of elpasolites activated by Tm³⁺ ions is analyzed with the help of standard and modified crystal field theories. Application of the modified approach reduces considerably the root-mean-square deviation between theoretical and experimental energy values. Crystal field and covalence parameters are determined, the latter being in good agreement with the covalence parameters calculated using microscopic models.     

Nuclear <Superscript>111</Superscript>Cd probes detect a hidden symmetry change at the γ → α transition in cerium considered isostructural for 60 years

We use the time-differential perturbed angular correlation technique to study nuclear electric quadupole hyperfine interactions of probe ¹¹¹Cd nuclei in cerium lattice sites at room temperature under pressures up to 8 GPa. We have found that the well known γ → α phase transition in cerium is not isostructural. In α-Ce, the probe ¹¹¹Cd nuclei reveal a quadrupole electron charge density component that is absent in γ-Ce. The hidden spacial structure of electronic quadrupoles in α-Ce is triple-q antiferroquadrupolar, as was suggested in [14]. We relate our findings to the current understanding of the γ → α phase transition and also report on nuclear quadrupole interactions in other high-pressure phases of cerium: α″ (C2/m space symmetry) and α′ (α-U structure).     

Polymer particles containing Fe-based metalloporphyrin as a highly efficient stimulator of reactive oxygen species formation in vitro and in vivo

Russian Chemical Bulletin - Reactive oxygen species are generated by the redox reaction involving metalloporphyrin and ascorbic acid (AA) and lead to oxidative stress followed by cancer cell death....     

Doping-induced temperature evolution of a helicoidal spin structure in the MnGe compound

The helicoidal magnetic structure of a MnGe compound doped with 25% Fe is studied by means of small-angle neutron scattering in a wide temperature range of 10–300 K. Analysis of the scattering-function profile demonstrates that magnetic structures inherent to both pure MnGe and its doped compounds are unstable. The doping of manganese monogermanide is revealed to lead to higher destabilization of the magnetic system. In passing from MnGe to Mn_0.75Fe_0.25Ge, the magnetic-ordering temperature T _N decreases from 130 to 95 K, respectively. It is demonstrated that, at temperatures close to 0 K, the intensity of the contribution to scattering from stable spin helices decreases and the intensity of scattering by spin helix fluctuations increases with increasing impurity-metal concentration. An increased intensity of anomalous scattering caused by spin excitations existing in the system is observed. Helicoidal fluctuations and spin excitations corresponding to low temperatures indicate the quantum nature of the instability in the doped compound. However, MnGe doping with Fe atoms has no influence on the compound’s magnetic properties at temperatures of higher than T _N. The temperature range of short-range ferromagnetic correlations is independent of concentrations and is restricted by temperatures T ranging from 175 to 300 K.