Oleksii Brusylovets

Effects of Dispersion and Ultraviolet/Ozonolysis Functionalization of Graphite Nanoplatelets on the Electrical Properties of Epoxy Nanocomposites

The influence of liquid dispersive mediums used in the fabrication of graphite nanoplatelets (GNPs) on their morphology as well as the surface state and electrical conductivity of GNPs/epoxy nanocomposites (NCs) was studied in detail. Ultrasonic dispersion of thermally expanded graphite (TEG) in alcohol medium has been found to be the most effective by the time parameter and allows fabrication of GNPs with rather high aspect ratio (102) and low level of defects. Ultrasonic dispersion of TEG in water medium requires a long time (up to 20 h) of ultrasonic action, but the resulting GNPs are characterized by large lateral size and, therefore, a higher aspect ratio (104). The effects of different ultraviolet (UV)/ozone treatment time on GNPs/epoxy NCs morphology and electrical properties were investigated by optical microscopy, scanning electron microscopy (SEM), infrared (IR) spectrometry, and Raman spectroscopy. The NCs with GNPs subjected to UV/ozone treatment have shown the increase of electrical conductivity with the increase of UV/ozone treatment time, which can be associated with the improved dispersion and distribution of GNPs within the epoxy matrix as well as decreased contact resistance between individual GNPs in conductive network due to chemical functionalization of GNPs during UV/ozone treatment.

Asymmetric magnetoresistance in the graphite intercalation compounds with cobalt

ABSTRACT The results of measurements of the magnetoresistance for graphite intercalation compounds with cobalt based on highly oriented pyrolytic graphite and fine crystalline pyrolytic graphite in the temperature range from 1.6 K to 293 K and in a magnetic field up to 16 T are presented. For the investigated intercalation compounds, the effect of asymmetry of the magnetoresistance relative to the magnetic field direction is revealed. It is shown that this effect can be satisfactorily explained within the Segal model of asymmetric magnetoresistance in thin films with large magnetic anisotropy.

Reactions of (iPrO)3MM(OiPr)3 (M = Mo, W) with low-coordinate phosphorus compounds. Formation of the first four-membered planar metallacycles, containing an MM triple bond

The low-coordinate phosphorus compounds (Me(3)Si)(2)N-P=NSiMe(3), (Me(3)Si)(2)N-P(=S)=N(t)Bu and (Me(3)Si)(2)N-P(=NSiMe(3))(2) react with ((i)PrO)(3)M≡M(O(i)Pr)(3) (M = Mo, W) to form four- and five-membered metallacycles with intact endocyclic or exocyclic M≡M triple bonds. The first four-membered planar metallacycles, containing an M≡M triple bond were obtained in reaction with (Me(3)Si)(2)N-P=NSiMe(3).

(N,N,N',N'-Tetra-methyl-ethylenediamine-κN)bis-(2,4,6-trimethyl-phenolato-κO)germanium(II).

In the title compound, [Ge(C9H11O)2(C6H16N2)], the GeII atom is coordinated in a distorted trigonal–pyramidal geometry by two O atoms belonging to two 2,4,6-trimethylphenolate ligands and one N atom of a tetramethylethylenediamine ligand. Comparing the structure with published data of similar compounds shows that the Ge—O bonds are covalent and the Ge—N bond is coordinated.

Crystal structure of O-isopropyl [bis-(tri-methyl-sil-yl)amino](tert-butyl-amino)-phosphino-thio-ate.

[Bis(trimethylsilyl)amino](tert-butylimino)thiophosphorane reacts in benzene with isopropyl alcohol via 1,2-addition of an iPrO–H bond across the P=N bond, resulting in the title compound, C13H35N2OPSSi2. In the molecule, the P atom possesses a distorted tetrahedral environment involving two N atoms from (Me3Si)2N– and tBuNH– groups, one O atom from an iPrO group and one S atom, therefore the molecule has a stereocenter on the P atom but crystal symmetry leads to a racemate. In the crystal, a pair of enantiomers form a centrosymmetric dimer via a pair of N—H⋯S hydrogen bonds.

Tetra­chloridodi-μ3-oxido-tetra­kis­(μ2-propan-2-olato-κ2O:O)ditin(II)ditin(IV)

The centrosymmetric tetranuclear title molecule, [Sn4(C3H7O)4Cl4O2], contains two types of Sn atoms, SnII and SnIV. The SnII atom has a trigonal–pyramidal coordination environment and is bonded to two O atoms from two isopropanolate groups and one μ3-oxide atom. The SnIV atom has an octahedral coordination environment, formed by two chloride atoms, two μ3-oxide atoms and two O atoms from isopropanolate groups.

Bis(μ-propan-2-olato-κ2O:O)bis­[chlor­ido(propan-2-ol-κO)bis­(pro­pan-1-ol­ato-κO)tin(IV)]

The binuclear centrosymmetric title compound, [Sn2(C3H7O)6Cl2(C3H8O)2], exhibits an edge-shared double octahedral exhibits an edge-shared octahedral structure, which is distorted owing to the presence of asymmetric intramolecular hydrogen bonds between the axially coordinated isopropanol and isopropoxide ligands. The H atom of the hydroxy group is located nearer to an isopropoxy group with the longest Sn—O bond [2.1789 (17) Å].