[en] The morphology of the surface of thin films of uranium bis-phthalocyanine and its pyrolysed derivatives is analyzed by atomic-force microscopy. During the pyrolysis of samples in an inert atmosphere (400–800°C), the transition from a crystalline to amorphous carbon structure with immobilized metal atoms is observed in uranium bis-phthalocyanine thin films deposited onto a substrate. It is found that at temperatures above 1000°C the pyrolysis is accompanied by the aggregation of nanoscale particles and the formation of ultraporous matrices with a high specific surface area (∼102 m²/g).

[en] Encapsulation of metal atoms inside carbon single-wall cages or within multi-layer cells has been realized using molecular precursors and high temperature processes transforming them into desirable structures. Endohedral fullerenols Fe@C₆₀(OH)_X with 3d-metal (iron) have been studied by SANS in aqueous solutions where they form stable globular clusters with radii R _C ∼ 10-12 nm and aggregation numbers N _C ∼ 10⁴. This self-assembly is a crucial feature of paramagnetic fullerenols as perspective contrast agents for Magneto-Resonance Imaging in medicine. Cellular carbon-metal structures have been created by the pyrolysis of diphthalocyanines of lanthanides and actinides. It was established that these ultra porous matrices consist of globular cells of molecular precursor size (∼ 1 nm) which are aggregated into superstructures. This provides retain of metal atoms inside matrices which may serve for safety storage of spent fuel of nuclear power plants. (paper)

[en] A project of the center for studying reactor materials and solving problems of materials science is presented which will be equipped with the following neutron instruments: a small-angle Membrana diffractometer, a spin-echo spectrometer, and a time-of-flight spectrometer. It is proposed to irradiate materials in the PIK reactor core and use neutron-scattering tools to analyze the structure and dynamics of these materials and investigate radiative defects in the complete experimental cycle (initial material-irradiation-strength tests, thermal loads, and other effects) using materials science techniques.

[en] Recent results on structural studies of aqueous solutions of water-soluble derivatives of endofullerenes encapsulating 4f- and 3d-elements have been presented. Neutron small angle scattering experiments allowed recognize subtle features of fullerenols assembly as dependent on chemical nature (atomic number) of interior atom, pH-factor and temperature of solutions. It was observed a fractal-type fullerenols’ ordering at the scale of correlation radii ∼ 10-20 nm when molecules with iron atoms are integrated into branched structures at low concentrations (C ≤ 1 % wt.) and organized into globular aggregates at higher amounts (C > 1 % wt.). On the other hand, for Lanthanides captured in carbon cages the supramolecular structures are mostly globular and have larger gyration radii ∼ 30 nm. They demonstrated a good stability in acidic (pH ∼ 3) and neutral (pH ∼ 7) media that is important for forthcoming medical applications. (paper)

[en] The parameters of an electric-arc facility for the synthesis of fullerenes and endohedral metallofullerenes are optimized. The resistance of C_6_0 and C_7_0 fullerenes and C_6_0(OH)_3_0 and C_7_0(OH)_3_0 fullerenols against neutron irradiation is studied. It is established that the radiation resistance of the fullerenes is higher than that of the fullerenols, but the radiation resistance of the Gd@C_2_n endometallofullerenes is lower than that of the corresponding Gd@C_2_n(OH)_3_8 fullerenols. The radiation resistance of mixtures of Me@C_2_n(OH)_3_8 (Me = Gd, Tb, Sc, Fe, and Pr) endometallofullerenes with C_6_0(OH)_3_0 is determined. The factors affecting the radiation resistance of the fullerenes and fullerenols are discussed.

[en] The endohedral metallofullerenols Me@C_2_n(OH)_3_8_–_4_0 + C_2_n(OH)_3_8_–_4_0 (Me = Tb, Sc, Gd, Fe, Pr, Mo) have been obtained and their radiation resistance under irradiation by a neutron flux of 8 × 10"1"3 cm"–"2 s"–"1 has been studied. The factors affecting the radiation resistance of endohedral metallofullerenols are discussed.

[en] Endohedral lanthanide metallofullerenes and their water-soluble biocompatible derivatives have been synthesized. The effect that fast-neutron irradiation has on the stability and nuclear physical properties of endohedral metallofullerenes that are used as magnetocontrast materials (⁴⁶Sc, ¹⁴⁰La, ¹⁴¹Nd, ¹⁵³Sm, ¹⁵²Eu, ¹⁵⁴Eu, ¹⁵³Sm, ¹⁶⁰Tb, ¹⁶⁹Yb, ¹⁷⁰Tm (isomers I and III), and ¹⁷⁷Lu) is studied. Our hypothesis, according to which carbon-shell relaxation is based on the fast nonradiative processes of an electron shake-off type, is confirmed.

[en] Endohedral metallofullerenes Me@C_2n (n = 30–50), their hydroxylated derivatives Me@C_2n(OH)_38–40 (Me = Tm, Ho, Eu, Sm, Co), and fullerenol С₆₀(OH)₃₈ have been synthesized The radiation resistance of these structures under irradiation in reactor by thermal and fast neutron fluxes in the fluence range of 1018–1019 cm^–2 (cadmium ratio of ~10) has been analyzed. Endofullerenols are shown to be more stable in comparison with initial endohedral fullerenes; the molecules containing Eu and Sm (atoms characterized by the largest slow-neutron absorption cross section) turned out to be most stable. The mechanism of the formation of secondary Eu and Sm endofullerenols is discussed taking into account the neutron capture and emission of γ quanta by excited nuclei, which acquire the recoil energy.

[en] Structural peculiarities of ferroelastomers composed of polydimetylsiloxane with embedded magnetite particles during polymerization have been studied by small-angle neutron scattering. The effects of ferroparticles’ concentration in the range of C = 0–6 wt %, and external magnetic fields of induction B = 0−1 kG applied during the polymerization on the structure of polymeric matrix and particles distribution in polymer were analyzed.

[en] The structure of detonation diamonds sintered at a high pressure (7 GPa) and temperatures of 1200–1700°C has been investigated by small-angle neutron scattering. It is shown that sintering leads to an increase in the particle size from 6 to 30 nm and established that this increase is due to the chainlike oriented attachment of particles. This study supplements the oriented-attachment model, which was suggested based on the X-ray diffraction spectra of detonation nanodiamonds (DNDs) sintered under the same conditions.