Conversion of isopropyl alcohol to acetone in fullerite cavities

Fullerite with cavities containing dichlorobenzene (DCB) and isopropyl alcohol (IPA) molecules was prepared by the addition of IPA to a solution of fullerene C₆₀ in DCB. On heating in vacuo fullerite evolves IPA, and the temperature increase to 200—350 °C results in the evolution of acetone. No products of DCB conversion were observed. Possible products of the interaction of 60 with two IPA molecules were calculated by the quantum chemical method. New data on the fullerite structure were obtained by transmission electron microscopy X-ray powder diffractometry, mass spectrometry, IR spectroscopy, and other methods. One of the possible mechanisms of the reaction IPA → acetone was considered.     

Magnetoactive Humic-Based Nanocomposites

Summary: We have elaborated several approaches for the preparation of magneto-active nano-hybrid composites, including i) ex situ method, which consists of the precipitation of magnetic particles from Fe(II) and Fe(III) salts followed by their incorporation into the humic acids matrix and ii) a chemical precipitation method in situ where the magnetic particles are grown within the humic acids matrix. It was proven that adsorption of humic acids on the magnetic particle surface leads to an enhanced electrostatic and steric stabilization of particles, due to the absorbed layer of highly charged macromolecular compounds. The sorbents under study were found to reveal a high sorption capacity towards uranyl ions. Using the adsorption isotherm, in the linear form of the Langmuir equation, the adsorption parameters were estimated. The results obtained show that the adsorption of uranyl ions by the magneto-active nanocomposite is enhanced in comparison with the free HA.     

Effect of a magnetic field on the electroluminescence intensity of single-crystal ZnS

After exposure of single-crystal ZnS with microscopic twinning to magnetic fields of 1–10 T, the integral electroluminescence brightness is found to increase by several times. It is proposed that the magnetic field facilitates relaxation of a metastable state of the structural defects. Fiz. Tverd. Tela (St. Petersburg) 41, 1944–1947 (November 1999)     

The main approaches for description of the topochemistry of macromolecular metal complexes

The topochemistry of the distribution of metal complexes on macromolecule ligands is studied on an example of macrocomplexes obtained by the interaction of transition metal compounds (MX_n) with functional groups of the grafted layer (PE-gr-polyallylamine, PE-gr-polyacrylic acid, PE-gr-poly-4-vinylpyridine, etc.). Three main types of macrocomplexes are found out: I - isolated complexes (r̄ ≥ 15 Å); II - the aggregations of cluster types (complexes of paramagnetic metals unbounded chemically between each other) (r̄ ≤ 7 Å). III - clusters with a strong exchange interaction (exchange-bound clusters caused by chemical bonds of complexes similar to polynuclear complexes). The ratio and distances between complexes of differen types as well as their possible role in catalytic processes are estimated and discussed.     

Macromolecule — Metal complexes based on salts of unsaturated mono- and dicarboxylic acids: Synthesis and characterization

The radical polymerization and copolymerization of salts of unsaturated carboxylic acids were used for the production of metal-containing polymers. The kinetic peculiarities and copolymerization parameters were estimated. The synthesis and structure of transition metal acrylates, maleates, fumarates, and itaconates are discussed. The influence of the metal atom on salt reactivities and reaction rates is observed.     

Magnetic properties of polymer matrix nanocomposites on a basis of metal carboxylates

Metallopolymer nanocomposites on the bases of cobalt and iron acrylates as well as their cocrystallites have been obtained and characterized. Microstructure of the materials consists of both agglomerated and individual nanocrystallites which are homogeneously distributed in the polymer matrix. Mean crystallite size is 7-14 nm. All the composite materials exhibit soft magnetic properties at room temperature. The magnetic parameters are controlled by the intrinsic magnetic properties of the constituents and agglomeration of the particles.     

Estimates for the entropy numbers of the Nikol'skii–Besov classes of functions with mixed smoothness in the space of quasi-continuous functions

We obtained order estimates for the entropy numbers of the Nikol'skii–Besov classes of functions $B_{p,\theta }^{\mathit{r}}({\mathbb{T}}^d)$ with mixed smoothness in the metric of the space of quasi-continuous functions $QC({\mathbb{T}}^d)$. We also showed that for $2\le p\le \infty$, , $r_1>\frac{1}{2}$, $d\ge 2$, the estimate of the corresponding asymptotic characteristic is exact in order.     

Macromolecule complexes of unsaturated polynuclear metal oxocarboxylates

Transition metal μ₃-oxo-carboxylates on the base of acrylic, maleic, itaconic, and acetylenedicarboxylic acids are first obtained and characterized using the elemental analysis, IR spectroscopy, EXAFS, magnetochemistry, and mass-spectrometry. The metal atoms form a trinuclear cluster core with oxygen atom in the center and bridge carboxylate ligands. For maleate Fe(III), the lengths of Fe - Fe, Fe - O_bridge, Fe - O_ligand bonds are equal to 3.29, 1.94, and 2.03 Å, respectively. For polymer metal oxo-acrylates molecular-weight characteristics and topology structure are analyzed. They are network amorphous or amorphous-crystal metal-containing polymers.     

Combined XPS and AFM study of cluster-containing polymers based on Rh

Rh₆- monomer and polymer-immobilized complexes have been characterized using XPS and AFM. Polymer-immobilized clusters were obtained by the reaction of Rh₆(CO)₁₅CH₃CN with copolymer of allyldiphenylphosphine and styrene. AFM study shows the change of surface morphology of the above copolymers. XPS data demonstrated the change of charge state of Rh atoms under monosubstitution of the CO-group for Rh₆- monomer complexes as well as in copolymer cluster complexe after the catalysis process of hydrogenation.