Using various solvents (dioxane, n-butanol, isopropanol, ethanol, acetonitrile, dimethyl sulfoxide), the cogelation of methyltrimethoxysilane and tetraethoxysilane in a molar ratio of 1 : 1 was carried out. The resulting gels were dried in supercritical carbon dioxide to obtain SiO2 aerogels, which possessed specific surface areas of 1000–1500 m2/g, apparent densities of 0.055–0.095 g/cm3, and porosities of 95–99

An ever-increasing number of applications of oxide aerogels places a high demand on wettability-tuning techniques. This work explores the possibility to cheaply prepare GeO2 aerogels with controlled wettability by an ambient pressure drying (APD) method. GeO2 aerogels are prepared via two synthetic routes. Surface modification is carried out by soaking the gels in a silylating agent solution; type and concentration of the modifier are optimized to achieve a large surface area. The aerogels have been characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, nitrogen adsorption and contact angle measurements. The effect of surface modification on the phase composition and particle size of the aerogels is described. In summary, the work provides a new cheap production method for the preparation of both hydrophobic and hydrophilic GeO2 aerogels with contact angle varying from 30° to 141° and with surface area of 90–140 m2/g, which facilitates the expansion of their diverse applications. GeO2 aerogel synthesis by APD is reported for the first time.

New composite materials (ionogels) have been obtained based on imidazolium ionic liquids immobilized in highly porous polymers, i.e., polyamide 6,6 (nylon 6,6) and low-density polyethylene. A method has been proposed for determining the rate of ionic liquid removal from an ionogel upon contact with water, with this method being based on continuous measuring the conductivity of an aqueous phase. The results of the conductometric measurements have been confirmed by high-performance liquid chromatography data. It has been shown that the stability of ionogels upon contact with water is determined by both the hydrophobicity of a polymer matrix and the solubility of an ionic liquid in water. The highest degree of ionic liquid removal (more than 80%) has been observed for composites based on porous polyamide 6,6 (hydrophilic matrix) and dicyanimide 1-butyl-3-methylimidazolium (completely miscible with water). Ionogels based on low-density polyethylene (hydrophobic matrix) and bis(trifluoromethylsulfonyl)imide 1-butyl-3-methylimidazolium (poorly soluble , <1 wt %, in water) have shown the highest stability (washout degree of no more than 53% over 24 h). The method proposed for analyzing the rate of ionic liquid dissolution in water has been used to discuss the mechanism of this process.

The structure and hardness of an aluminum-matrix Al–Si–Cu-based material reinforced with WO3 nanoparticles via liquid phase mixing with a melt according to two versions, namely, using a mixture of WO3 with a copper powder and without it, are studied. The existence of transport effect of a copper powder, which ensures a uniform distribution of WO3 nanoparticles in the composite volume, is confirmed. The most homogeneous structure and a high hardness of the composite material are reached in the case of introduction of a mixture of 1 wt

The effect of 6 types of jet treatment and electrolytic plasma polishing on the roughness and wettability of the surface and interaction with the bacterium Escherichia coli of two commercial titanium-based alloys used in medicine, VT1-0 (pure titanium) and VT6 (titanium alloy with aluminum and vanadium) and Ti alloy developed at IMET RAS was studied-Nb-Zr. It is noted that all created surfaces are wettable, the wetting angle is naturally higher the lower the surface roughness, however, in the case of all materials after sandblasting with mixtures with a wide range of particles in size, an increase in the wetting angle is noted. All metal samples do not have antibacterial activity and do not contribute to the formation of a sterile zone. However, when studying the ability to form biofilms from the bacterium Escherichia coli on the surface of metals. It was found out that their number is significantly lower compared to the control, which was cultivated under ideal conditions for the growth of this bacterium. The alloy under development, which potentially has better biomechanical compatibility than the commercial ones used, did not show a deterioration in surface characteristics and an effect on the growth of bacteria.

The parameters of gel synthesis affect the kinetics and mechanism of hydrolysis and condensation processes, thereby determining the three-dimensional porous structure. In this work, the characteristics of germanium dioxide aerogels were investigated depending on the conditions of preparation. Acetonitrile was chosen as the optimal solvent, and hydrochloric acid was chosen as a catalyst. The concentrational ranges of stable gel existence during the hydrolysis of germanium(IV) tetraethoxide and tetraisopropoxide were determined. The effect of the choice of precursor and water content on the textural characteristics of the aerogel was shown. Mesoporous materials with a specific surface area of 50 m2/g with a wide pore size distribution were obtained. The phase composition of the obtained aerogels in all cases corresponded to the hexagonal modification of germanium dioxide.

A series of silica-based aerogels comprising novel bifunctional chelating ligands was prepared. To produce target aerogels, two aminosilanes, namely (3-aminopropyl)trimethoxysilane (APTMS) and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPTMS), were acylated by natural amino acids ((S)-(+)-2-phenylglycine or L-phenylalanine), followed by gelation and supercritical drying (SCD). Lithium tetrachloropalladate was used as the metal ion source to prepare strong complexes of Pd2+ with amino acids covalently bonded to a silica matrix. Aerogels bearing chelate complexes retain the Pd2+ oxidation state after supercritical drying in CO2, but the Pd ion is reduced to Pd metal after SCD in isopropanol. Depending on the structure of amino complexes, Pd-containing aerogels showed catalytic activity and selectivity in the hydrogenation reactions of C=C, C≡C and C=O bonds.

This paper reports on green chemistry approaches to the molecular design and synthesis of cheap, efficient and eco-friendly electrocatalysts of the hydrogen evolution reaction (HER). The title clathrochelates (including first those do not containing sulfur derivatives as "catalytic poisons") were prepared using nucleophilic substitution of their chloroclathrochelate precursors and characterized by analytical, spectral and XRD methods. These complexes showed the HER 2 H+/H2 electrocatalytic activity in the solutions. They form the Langmuir monolayers and possess a high physisorption on activated carbon (AC, up to 0.55 mmol center dot g-1) and reduced graphene oxide (RGO, up to 0.33 mmol center dot g-1). Contrary that on carbon paper (CP) is very low. Therefore, AC- or RGO-containing clathrochelate-immobilized components are suitable for preparation of hybrid CP-based cathodes, allowing to substantially increase a surface concentration of electrocatalytically active centers up to 0.5 mu mol center dot m-2. Cyclic voltammetry data suggest that the electrochemically generated cobalt(I) complexes, as the catalytically active intermediates, are stable and most prospective candidates for electrocatalytic hydrogen production. Clathrochelate-based single-atom catalysts were prepared in accordance with basic principles of green chemistry. They are derivatives of abundant and cheap 3d-biometals and low-toxic alpha-dioximes and possess an extremely high atomic utilization efficiency matching the "economy of atoms" principle. Nowadays, the carbon-supported metallic platinum is used as HER catalyst. The reserves of this noble and expensive metal on the Earth are limited and its replacement by such cheap and abundant HER materials will accelerate the development and implementation of green hydrogen-producing technologies. The recommendations on chemical structures of optimal molecular electrocatalysts were evaluated.

A synthetic approach to production of monolithic (NH4)3H(Ge7O16)(H2O)x and (NH4)2Ge7O15 aerogels is developed. Production of the aerogels with the germanate zeolite-like structure is reported for the first time. Thermal decomposition of (NH4)2Ge7O15 leads to formation of GeO2 aerogel, which has been obtained before using much more complex and expensive process of alkoxide hydrolysis. The suggested synthetic route might be used for production of novel luminescent, catalytic and anode materials. Luminescent properties of all obtained aerogels revealed excitation dependence. Based on excitation wavelengths it could exhibit blue, yellow-green and red luminescence. Luminescent properties for (NH4)3H(Ge7O16) (H2O)x and (NH4)2Ge7O15 are reported for the first time.

The behavior of cerium tetrafluoride hydrate was studied in water at a temperature of 80 degrees C and under hydrothermal treatment at 100, 130, and 220 degrees C for a day. The product of the hydrothermal treatment of CeF4H2O at 100 degrees C was investigated by chemical, thermogravimetric, IR spectroscopic, and X-ray powder diffraction analyses, which identified a new cerium fluoride with the composition, presumably, Ce3F10 & sdot;3H(2)O or, most likely, (H3O)Ce3F10 & sdot;2H(2)O. New compound crystallizes in the space group Fm3m with a unit cell parameter of 11.66 & Aring;. Hydrothermal treatment of cerium tetrafluoride hydrate at temperatures above 130 degrees C leads to hydrolysis and reduction of cerium(IV) fluoride compounds to form CeO2 and CeF3.

A fast method for preparing aqueous graphene oxide (GO) dispersions by electrochemical oxidation of a graphite anode without preliminary intercalation with oxidizing agents is proposed. Ultrasonic probing was used in the modulation mode of ultrasonic waves (work/rest) for more efficient graphite oxidation–exfoliation. It is shown that the 4/2 s mode of ultrasonic modulation is the most effective due to the probe material’s low corrosion while maintaining the optimum synthesis temperature not exceeding 30–35 °C and achieving the best characteristics of the resulting product. Three cases of anodic oxidation of graphite to obtain graphene oxide were considered: (1) a combined cathode–anode compartment, (2) a split cathode–anode salt-bridged compartment, and (3) separated anode compartment with a 3.5 kDa dialysis membrane. It was determined that the approach to synthesis with a divided cathode–anode compartment makes it possible to obtain GO sheets with fewer defects compared to chemical methods or methods with a combined cathode–anode compartment and makes it possible to control the oxidation degree of the material (C:O ratio) by varying the current density. The prepared samples showed good stability for more than six months. The spectral and morphological characteristics were studied. Using chemiluminometry in the luminol/Co(II)/H2O2 system, the antioxidant properties concerning three key reactive oxygen species (H2O2, superoxide anion radical, and hydroxyl radical) were demonstrated. It was also shown that the prepared GO dispersions do not induce lipid and phospholipid peroxidation.

The behavior of cerium tetrafluoride hydrate was studied in water at a temperature of 80°C and under hydrothermal treatment at 100, 130, and 220°C for a day. The product of the hydrothermal treatment of CeF 4 ·H 2 O at 100°C was investigated by chemical, thermogravimetric, IR spectroscopic, and X-ray powder diffraction analyses, which identified a new cerium fluoride with the composition, presumably, Ce 3 F 10 ⋅3H 2 O or, most likely, (H 3 O)Ce 3 F 10 ⋅2H 2 O. New compound crystallizes in the space group Fm3̅m with a unit cell parameter of 11.66 Å. Hydrothermal treatment of cerium tetrafluoride hydrate at temperatures above 130°C leads to hydrolysis and reduction of cerium(IV) fluoride compounds to form CeO 2 and CeF 3 .

The enzyme-like activity of metal oxide nanoparticles is governed by a number of factors, including their size, shape, surface chemistry and substrate affinity. For CeO2 nanoparticles, one of the most prominent inorganic nanozymes that have diverse enzymatic activities, the size effect remains poorly understood. The low-temperature hydrothermal treatment of ceric ammonium nitrate aqueous solutions made it possible to obtain CeO2 aqueous sols with different particle sizes (2.5, 2.8, 3.9 and 5.1 nm). The peroxidase-like activity of ceria nanoparticles was assessed using the chemiluminescent method in different biologically relevant buffer solutions with an identical pH value (phosphate buffer and Tris-HCl buffer, pH of 7.4). In the phosphate buffer, doubling CeO2 nanoparticles' size resulted in a two-fold increase in their peroxidase-like activity. The opposite effect was observed for the enzymatic activity of CeO2 nanoparticles in the phosphate-free Tris-HCl buffer. The possible reasons for the differences in CeO2 enzyme-like activity are discussed.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The reaction of copper(II) acetate with 3-furancarboxylic acid (Hfur) and 5-nitro-2-furancarboxylic acid (Hnfur) with participation of 4-phenylpyridine (phpy) in acetonitrile resulted in mononuclear complexes [Cu (L)(2)(phpy)(2)(H2O)]center dot solv (L = fur (1), nfur (2); solv = phpy (1)) whose structures were determined by direct single crystal X-ray analysis. According to X-ray data, the complexing component in 1 and 2 is in a distorted square -pyramidal environment (CuN2O3); the pyramid base is formed by monodentate-bound oxygen atoms of fur(-)/nfur(-) anions and a pair of nitrogen atoms of the phpy moieties, while the water molecule occupies an axial position. It was found for the first time that copper nanoparticles immobilized on the surface of gamma-Al2O3 obtained by chemical reduction of 1 and 2 (pre-deposited on the surface from solution) with sodium tetrahydroborate show high selectivity of monohydrogenation of tricyclo[5.2.1.0(2,6)]deca-3,8-diene (dicyclopentadiene, DCPD) to give tricyclo[5.2.1.0(2,6)]dec-4-ene (5,6-dihydrocyclopentadiene, DHDCPD). The catalytic activity tests show high selectivity (up to 100 %) of the catalysts studied in the reaction of partial hydrogenation to DHDCPD under continuous process conditions even at high conversion values (up to 96 %) and with hydrogen present in excess. Thermal behavior of 1 and 2 was studied by simultaneous thermal analysis (STA).

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Nanoporous carbon (carbide-derived carbon (CDC)) has been prepared via high-temperature chlorination of a spherical NbC/C nanocomposite synthesized by a new process [ 19 ]. The CDC has been characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy in combination with energy dispersive X-ray analysis, and transmission electron microscopy. Using nitrogen adsorption–desorption measurements, we have determined the average pore size (3.627 nm), pore size distribution, and total pore volume (1.215 cm 3 /g) in the CDC and calculated its specific surface area by the BET method (817.282 m 2 /g). The electrochemical behavior of the nanoporous carbon (CDC) has been studied using half-cell cyclic voltammetry measurements in the potential sweep range from –1.0 to +1.0 V vs. carbon and impedance spectroscopy.

Cerium oxide nanoparticles (CeNPs) are among the most promising materials with pH-sensitive redox-activity for biomedical nanotechnologies.CeNPs are known to reduce the toxicity of the chemotherapeutic drug doxorubicin (DOX) for normal cells.Here we have proposed and analyzed a new hybrid cerium/silica containing SiNPs@DOX@CeNPs nanocomposite.We showed that the average size of the nanocomposite is 190 nm and it has a spherical shape.The SiNPs@DOX@CeNPs nanocomposite provides effective synergistic anticancer activity of CeNPs with doxorubicin (DOX), as well as selective toxicity against human osteosarcoma (MNNG/HOS) cells in vitro.The SiNPs@DOX@CeNPs nanocomposite may be a good candidate to increase the effectiveness of cancer doxorubicin chemotherapy.

The chemical immobilization of cobalt(II) ions in a silica aerogel matrix enabled the synthesis of the first representative example of aerogel-based single-ion magnets. For the synthesis of the lyogels, methyl-trimethoxysilane and N-3-(trimethoxysilyl)propyl ethylenediamine were co-hydrolyzed, then the ethylenediamine groups that were immobilized on the silica matrix enabled the subsequent binding of cobalt(II) ions. Lyogels with various amounts of ethylenediamine moieties (0.1–15 mol %) were soaked in isopropanol solutions of cobalt(II) nitrate and further supercritically dried in carbon dioxide to obtain aerogels with a specific surface area of 210–596 m2·g−1, an apparent density of 0.403–0.740 cm3·g−1 and a porosity of 60–78%. The actual cobalt content in the aerogels was 0.01–1.50 mmol per 1 g of SiO2, which could easily be tuned by the concentration of ethylenediamine moieties in the silica matrix. The introduction of cobalt(II) ions into the ethylenediamine-modified silica aerogel promoted the stability of the diamine moieties at the supercritical drying stage. The molecular prototype of the immobilized cobalt(II) complex, bearing one ethylenediamine ligand [Co(en)(MeCN)(NO3)2], was synthesized and structurally characterized. Using magnetometry in the DC mode, it was shown that cobalt(II)-modified silica aerogels exhibited slow magnetic relaxation in a nonzero field. A decrease in cobalt(II) concentration in aerogels from 1.5 mmol to 0.14 mmol per 1 g of SiO2 resulted in a weakening of inter-ion interactions; the magnetization reversal energy barrier likewise increased from 4 to 18 K.

The structure and hardness of an aluminum-matrix composite material based on an alloy of the Al—Si—Cu system reinforced with WO3 nanoparticles by liquid-phase mixing into a melt have been studied in two variants: mixed with copper powder and without it. The presence of the transport effect of copper powder, which provides a uniform distribution of WO3 nanoparticles in the bulk of the composite, was confirmed. The most uniform structure and high hardness of the composite material was achieved in the case of introducing a 1% (wt.) powder mixture of WO3 and Cu at their mass ratio 1:3.