Spectroelectrochemistry of Poly(3,4-Ethylenedioxythiophene)–Tungsten Oxide Composite Films in Dilute Sulfuric Acid Solution

Russian Journal of General Chemistry - Using electrochemical deposition of tungsten oxide from a metastable acidic solution of isopolytungstates into a poly(3,4-ethylenedioxithiophene) film,...     

Theoretical investigation of the adsorption and diffusion of hydrogen on the surface and in the bulk of the intermetallic compound Mg2Ni

The intermetallic compound Mg₂Ni as a potential material for hydrogen storage has been investigated theoretically. The sorption and diffusion of a hydrogen atom in the bulk and on the surface of this material, as well as the step-by-step process of dissociative chemisorption of a H₂ molecule on the surface, have been considered. The dependence of the sorption energy of atomic hydrogen on the structural characteristics of the intermetallic compound Mg₂Ni has been analyzed.     

Alkaline-Earth Metal Complexes with Pivaloylacetone

Pivaloylacetonates of alkaline-earth elements with composition M(Pa)₂ · nH₂O (n = 1, M = Sr, Ca; n = 0, 2, M = Ba) were synthesized and studied by IR and thermal analysis; their solubilities and volatility were estimated. It was found that the volatility changes regularly in the series M(Acac)₂–M(Pa)₂–M(Thd)₂ (HAcac is acetylacetone, HThd is dipivaloylmethane). The replacement of one methyl radical by the tert-butyl radical when going from acetylacetonates to pivaloylacetonates was shown to noticeably increase the volatility only for Sr(Pa)₂ · H₂O. Complexes of barium pivaloylacetonate with tetraglyme and -phenanthroline were synthesized and characterized.     

The volume characteristics of solution of naphthalene in heptane-ethanol mixtures at 298.15 K

The solubility of naphthalene was studied by the isothermal saturation method, and the density of naphthalene-heptane-ethanol solutions at 298.15 K was measured using an oscillating tube densimeter. The results were used to calculate the volume characteristics of naphthalene in the systems specified. The solubility of naphthalene in heptane was substantially higher than in ethanol. The composition dependences of apparent partial molar volumes contained extrema. The reason for such nonlinear dependences can be a sharp change in the contribution to the entropy of mixing related to the packing of molecules of different diameters (naphthalene and heptane). Another possible mechanism of these anomalies can be related to the stabilization of the structure of alkanols in the solvation sheath of alkanes noticed earlier.     

Lanthanide luminescence efficiency in eight- and nine-coordinate complexes: Role of the radiative lifetime

The photophysical parameters for the sensitization of metal-centred luminescence are analyzed in two series of complexes with tridentate and hexadentate ligands having N_xO_y chelating units. In particular, the radiative lifetime τ_rad is experimentally estimated for 29 nine-coordinate Eu^III complexes and 10 eight- and nine-coordinate Yb^III complexes. The known dependence of τ_rad on refractive index is substantiated by comparing data for solid-state samples and solutions. Moreover, a clear dependence of τ_rad with the coordination environment is evidenced and in the case of Eu^III, a comparison between τ_rad and the nephelauxetic effect generated by the ligands is attempted. Altogether, this extensive analysis points to the importance of having a handle on τ_rad when designing ligands for highly luminescent lanthanide-containing molecular edifices. This, in turn, should stimulate initiating theoretical considerations to unravel a reliable relationship between τ_rad and the electronic structure of the ligands.     

Hydrodynamic and bulk properties of dextrans in liquid media

Bulk and viscous properties of solutions of dextrans of different molecular weights in formamide, water, and dimethyl sulfoxide were studied. The fractal dimension of the biopolymer was estimated from the hydrodynamic data.     

Dispersion of Electromagnetic Waves in a Periodic Ferromagnet-Dielectric Structure

The special features of normal TE mode propagation in a periodic ferromagnet-dielectric structure are investigated. The magnetizing field is parallel to the boundary between the media and perpendicular to the mode propagation direction. The matrix of the structure period transformation, dispersion relation, and energy reflection coefficient are derived by solving the boundary problem for the normal wave incidence on a semi-infinite periodic medium. It is demonstrated that the reflected wave spectrum and characteristics can be controlled by an external field. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 69–75, May, 2005.     

Volume Characteristics of Lithium Salts in Alcohols

The densities of lithium chloride and nitrate in aliphatic alcohols (methanol, ethanol, 1- and 2-propanol, 1- and 2-butanol, and 1- and 2-pentanol) at 298.15 K in the salt concentration range from 0 to 3.5 mol kg^{- 1} were measured by means of vibrational densimeter. The resulting density data were used to calculate the apparent and partial molar volumes of the solvents and solutes.