Limiting partial molar volumes of solutions of oleic, linoleic, and linolenic acids in cyclohexane and benzene

High-precision vibration densimetry was used to measure (with an error of less than 5 × 10^?6 g/cm³) the density of dilute solutions (0≤ x ₂ ≤ 0.01 mole fractions) of oleic, linoleic, and linolenic acids in cyclohexane and benzene at 298.15 K. The limiting $\bar V_2^\infty $ and excess V ₂ ^{E, ∞} partial molar volumes of these C_{18: n} fatty acids in the indicated solvents were calculated. Benzene was demonstrated to selectviely influence the volumetric effects of dissolution (V ₂ ^{E, ∞} ) of the linoleic (n _C=C= 2) and linolenic (n _C=C = 3) polyunsaturated acids.     

Platinum(II) O,O′-diisobutyl dithiophosphate: Synthesis,structure, thermal properties,and solid-state <Superscript>13</Superscript>C, <Superscript>31</Superscript>P,and <Superscript>195</Superscript>Pt CP/MAS NMR spectra. Model of the structural state of platinum in cooperite

The complex bis(O,O′-diisobutyl dithiophosphato)platinum(II) (I) was obtained and characterized by solid-state ¹³C, ³¹P, and ¹⁹⁵Pt CP/MAS NMR spectroscopy. In complex I, the dithiophosphate fragments are structurally equivalent with a predominantly orthorhombic tensor of the ³¹P chemical shift (η = 0.73). The tensor of the ¹⁹⁵Pt chemical shift approximates to an axially symmetric one (for δ_zz> δ_xx and δ_yy), which suggests the existence of square chromophores [PtS₄], as in cooperite (natural PtS). The crystal and molecular structures of complex I were determined from X-ray diffraction data. The Pt atom coordinates two Dtph ligands in a S,S′-anisobidentate fashion (the Pt-S bonds are nonequivalent: 2.315 and 2.329 Å) to form two four-membered chelate rings [PtS₂P] with platinum as a spiro atom. The P-S bond length (1.997 and 1.986 Å), which is intermediate between the idealized lengths of the single and double phosphorus-sulfur bonds, suggests the delocalization of the π-electron density in the structural fragments PS₂. In complex I, the electron shielding of the platinum nucleus in the direction perpendicular to the plane of the chromophore [PtS₄] was found to be noticeably higher than that in cooperite. The thermal properties of complex I were examined by combined DSC-TG thermal analysis. The intermediate product of the thermolysis of complex I was platinum(II) dithiometaphosphate [Pt(S₂PO)₂] and the final thermolysis product was PtS.     

Electrical conductivity of solutions of the LiIO3-HIO3-H2O system

The electrical conductivity of aqueous LiIO₃ solutions and solutions of the LiIO₃-HIO₃-H₂O system is measured over a wide range of compositions at 25, 50, and 75°C. Isothermal surfaces of electrical conductivity are mapped, and the activation energies of conductivity are calculated. The conductivity isotherms in the LiIO₃-H₂O and HIO₃-H₂O boundary binary systems and in mixed solutions along sections with fixed electrolyte ratios each have a maximum as a function of electrolyte concentration. It is assumed that structure reorganization occurs in solutions in the concentration range corresponding to the peak conductivity. Proton migration features in the solutions in question are considered.     

Self-organization of polybases neutralized with mesogenic wedge-shaped sulfonic acid molecules: an approach toward supramolecular cylinders

Complexes consisting of poly(4-vinylpyridine) and mesogenic wedge-shaped ligands 4'-[3",4",5"-tris(dodecyloxy)benzoyloxy]azobenzene-4-sulfonic acid and 4'-[3",4",5"-tris(octyloxy)benzoyloxy]azobenzene-4-sulfonic acid have been prepared with different monomer/ligand ratios. Upon protonation of the poly(4-vinylpyridine) chains by the wedge-shaped sulfonic acid molecules a hypsochromic and hyperchromic effect was observed with the pi-pi* transition of the azo-chromophor, allowing us to monitor the neutralization process by means of UV-vis spectroscopy in solution. The changes of the absorption characteristics implied a conformational change of the polymer backbone. In the bulk the interaction between pyridine and sulfonic acid moieties was proved by FT-IR spectroscopy. Polarizing optical microscopy, differential scanning calorimetry, and X-ray diffraction measurements were used to study the bulk structure of the complexes. The complexes formed a liquid crystalline lamellar phase at low degrees of substitution, while a hexagonal columnar mesophase was observed at degrees of neutralization of 80% and higher.     

Gas-Sensitive Properties of SnO2-Based Thin Films Obtained from Film-Forming Solutions

Gas-sensitive properties of SnO₂ thin-film materials doped with antimony(III) with respect to the reducing gases CO, CH₄, and H₂ were studied. The materials were obtained from film-forming solutions of Sn(II) and Sb(III) complexes with acetylacetone.