Structural Nonhomogeneity of Low-Density Amorphous Ice and Its Effect on the Dynamics of Water Molecules

This paper reports on a molecular dynamics simulation of low-density (0.94 g/cm³) amorphous ice using Poltev–Malenkov's potential (729 particles, 101 K). The model is characterized by structural nonhomogeneity, manifesting itself as nonrandom arrangement of molecules with different nearest environments (different tetrahedricities of the nearest environment and different Voronoi polyhedron volumes). The nonhomogeneity regions are fractal, their typical size being 1 nm. The dynamic characteristics of the water molecules (motion amplitudes in a cage and vibrational spectra) differ from one structural region to another.     

Molecular and crystal structure of the clathrochelate complex FeDm3(BF)2⋅C6H6 and parameters of its 57Fe Mossbauer spectra

The molecular and crystal structure of the macrobicyclic complex FeDm₃(BF)₂C₆H₆ was established by X-ray diffraction analysis at 138, 208, and 291 K. The X-ray diffraction data were compared with the ⁵⁷Fe Mossbauer spectral parameters of this complex in the temperature range of 135-290 K. A substantial disagreement between the experimental values of quadrupole splitting and the corresponding values calculated based on the concept of partial quadrupole splitting was attributed to the displacement of the Fe atom from the center of the cavity of the macrobicyclic ligand and to the distortion of the axial symmetry of the electron density distribution about the metal atom.     

Supramolecular organization of the crystals of allylsulfide clathrochelate: influence of the nature of solvate molecules

The influence of the nature of solvate molecules on the supramolecular organization of the crystals of -benzyldioximate FeBd₂((AllylS)₂Gm)(BF)₂ clathrochelate containing the allylsulfide substituents was studied by X-ray diffraction analysis.     

Measurement of Dispersion Characteristics of Integrated Optical Microresonators and Generation of Coherent Optical Frequency Combs

Journal of Experimental and Theoretical Physics - Optical frequency combs are a unique tool for fundamental metrology, spectroscopy, and a broad spectrum of applications. High-Q microresonators...     

Unexpected radical substitution of the dichlorine-containing iron(II) clathrochelate with 1,4-dioxane derivatives: Novel approach to functionalization of its macrobicyclic framework

The dichlorine-containing tris-dioximate iron(II) clathrochelate undergoes a radical addition-elimination reaction with the radical derivatives of 1,4-dioxane to yield ribbed-functionalized C-alkylated macrobicyclic complexes. The clathrochelates obtained have been characterized using elemental analysis, MALDI-TOF mass, IR, UV-Vis and multinuclear NMR spectra, as well as X-ray crystallography. This unexpected and previously unknown radical reaction is a novel approach to the ribbed functionalization of tris-dioximate d-metal clathrochelates, and it can be extended to other cyclic ethers.     

Collective effects in diffusional motion of water molecules: computer simulation

Structural Chemistry - Molecular dynamics simulation of the system containing 3,456 water molecules in the cubic periodic box was performed. Virtual temperatures were 261 and 297&;nbsp;K....     

Cage complexes of transition metals in biochemistry and medicine

The review presents the following main trends and the perspectives of application of the transition metal clathrochelates in medicine and biochemistry: encapsulation of radioactive metal ion for diagnostics and therapy; imaging agents for MRI; antidotes and prolonged pharmaceuticals; pharmaceuticals for boron neutron capture therapy; antihelminthic and antiparasitic detergents; antioxidants; membrane transport of the metal ions; interaction of the cage metal complexes with nucleic acids and the potential of their self-assembling reactions in immunology and molecular biology (recognition of antibodies, antigens and DNA sites); design of HIV inhibitors for the therapy. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 555–582, April, 2007.