Adsorption of compounds with the skeleton molecular structure from dimethylsulfoxide solutions on mercury electrode

The adsorption of adamantane (Ad), adamantanol (AdOH), thiocamphor (TC), and a supramolecular complex (cryptate) of sodium ion [Na⁺ ⊂ 2.2.2.] from DMSO solutions on the mercury electrode is studied by the differential capacitance method. In the considered systems, the surfactants exhibit the high surface activity, which manifests itself in different ways depending on the potential scan direction. For AdOH, TC, and [Na⁺ ⊂ 2.2.2.] that have either a dipole moment or an electrostatic charge, it is assumed that the important role is played by the adsorbate-solvent interaction at the interface, which can be the key factor determining the formation of a new adsorption layer structure in the positive potential range. The adsorption behavior of the mentioned group of surfactants radically differs from that of Ad hydrocarbon, namely, the adsorption of the latter is not accompanied by the formation of a new adsorption layer structure. The obtained results suggest that for the adsorption of surfactants from nonaqueous solvents (in contrast to aqueous solutions), the interaction between the adsorbate and the solvent molecules, which under certain condition results in the formation of two-dimensional supramolecular structures at the electrode/solution interface, acquires substantial importance.     

Predicting the solubility of xenon in n-hexane and n-perfluorohexane: a simulation and theoretical study

The solubility of xenon in n-hexane and n-perfluorohexane has been studied using both molecular simulation and a version of the SAFT approach (SAFT-VR). The calculations were performed close to the saturation line of each solvent, between 200 K and 450 K, which exceeds the smaller temperature range where experimental data are available in the literature. Molecular dynamics simulations, associated with Widom's test particle insertion method, were used to calculate the residual chemical potential of xenon in n-hexane and n-perfluorohexane and the corresponding Henry's law coefficients. The simulation results overestimate the solubility of xenon in both solvents when simple geometric combining rules are used, but are in good agreement if a binary interaction parameter is included. With the SAFT-VR approach we are able to reproduce the experimental solubility for xenon in n-hexane, using simple Lorentz-Berthelot rules to describe the unlike interaction. In the case of n-perfluorohexane as a solvent, a binary interaction parameter was introduced, taken from previous work on (xe + C₂F₆) mixtures. Overall, good agreement is obtained between the simulation, theoretical and experimental data.     

Electrochemical defluorination of carbon nanotubes

An electrochemical procedure for the removal of fluorine from the walls of fluorinated monolayer carbon nanotubes was suggested. According to element analysis data, fluorine was completely removed. According to UV-Vis-Nir and Raman spectroscopic studies, the initial structure of fluorinated carbon nanotubes was almost completely restored.     

Effect of Plasma-Assisted Electrochemical Treatment of Glassy Carbon Electrode on the Reversible and Irreversible Electrode Reactions

Russian Journal of Electrochemistry - A glassy carbon electrode is modified by generating cathodic and anodic electrolytic plasma near its surface. Voltage pulses of amplitude up to 250 V, pulse-on...     

The Cu(II) complexes with bis(pyrazole-1-yl)methane and its derivatives: Synthesis,crystal structure,and magnetic properties

The procedures for the synthesis of the Cu(II) complexes with bis(pyrazole-1-yl)methane (L¹), bis(3,5-dimethyl-4-bromopyrazole-1-yl)methane (L²), and bis(3,5-dimethyl-4-iodopyrazole-1-yl)methane (L³) of the composition Cu₂(L¹)₂Br₄ (I), Cu₂(L²)₂Cl₄ (II), Cu(L³)(NO₃)₂ (III), and Cu(L³)(H₂O)(NO₃)₂ · 2H₂O (IV) were developed. The organic ligands in the above complexes are coordinated to Cu(II) in a bidentate cyclic type through the N(2), N(2′) atoms of the pyrazole rings. The molecular and crystal structures of L², L³, II, III, and IV were determined by X-ray diffraction. The study of the μ_eff(T) function in a temperature interval 2–300 K showed that compound I, which exhibited ferromagnetic exchange interactions in the chains, undergoes transition to antiferromagnetic state with weak ferromagnetism. The exchange antiferromagnetic interactions predominate in compound II.     

Nonlinear Third-Order Optical Properties in Polymer Ferroelectrics Doped with Ruthenium Phthalocyaninates

Crystallography Reports - The nonlinear optical properties of thin-film materials based on a copolymer of vinylidene fluoride with trifluoroethylene doped with ruthenium...     

Photoelectric, nonlinear optical, and photorefractive properties of polymer composites including carbon nanotubes and cyanine dyes

The effect of cyanine dye additives on the photoelectric, nonlinear optical, and photorefractive properties of polyvinyl carbazole composites based on closed single-walled carbon nanotubes has been investigated. It has been found that these characteristics are affected by the dye in which the lowest unoccupied molecular orbital (LUMO) lies below the level of the photoexcited nanotube. The addition of this dye to the composite leads to a 14-fold increase in the quantum efficiency of the generation of mobile charge carriers under irradiation by a laser (1064 nm) in the absorption region of the nanotubes. Moreover, the addition of the dye to the composite decreases the third-order susceptibility χ⁽³⁾, presumably, due to the opposite orientations of dipoles of the dye and the nanotube upon adsorption of the dye on the nanotube. The addition of the dye to the composite also provides a twofold increase in the two-beam photorefractive amplification factor of the laser beam with a wavelength of 1064 nm. The obtained values of the two-beam photorefractive amplification factor reach 120 cm^?1.     

Third-order optical susceptibility of single-walled carbon nanotubes

The third-order susceptibility of tetrachloroethane dispersions of capped single-wall carbon nanotubes (SWCNT) has been analyzed by the z-scan technique using a femtosecond laser, and the SWCNT image obtained by atomic force microscopy has been also presented.