Russian Chemical Bulletin最新文献

An approach was developed to the synthesis of two types of binuclear Pt^II complexes: complexes with azaheterocyclic carrier ligands based on imidazole as a linker and iodide anions as leaving groups, and complexes based on pyromellitic acid as a ligand, acting as a linker and a leaving group, and a pyrazole moiety as a carrier ligand. The antiproliferative activity of both mononuclear and binuclear complexes based on monodentate pyrazoles was found to depend on a combination of substituents at the pyrazole nitrogen atom and the nature of the leaving group. Binuclear Pt^II complexes with alkyl-1H-pyrazoles as carrier ligands exhibit high activity in the A2780C is cisplatin-resistant cell line.

Experiments on the homocondensation of methyl ethyl ketone (MEK) in a hydrogen atmosphere using monometallic supported catalysts (Ca, Zn, Cu, Cr, Mn, Ni, Pd) and active carbon as a support were carried out. The temperature effect on the conversion of MEK and selectivity of formation of 5-methyl-3-heptanone and 3-methylheptane was studied for each catalyst. The metals of different nature exhibit catalytic activity in the conjugate condensation—hydrogenation of MEK, and palladium, zinc, and nickel are of most interest for subsequent investigation.

Condensation of ethylenedinitramine with hydroxylamine or its O-alkyl-substituted derivatives and formalin resulted in the formation of 3-RO-1,5-dinitro-1,3,5-triazepanes. The structures of synthesized N-hydroxytriazepanes were confirmed by multinuclear NMR spectroscopy and X-ray crystallography.

The possibility of introducing ruthenium ions into hydroxyapatite (HAP) with the formation of a HAP—Ru complex via the cocrystallization and sorption routes was shown. The morphology of the HAP—Ru composite depends on the Ru/Ca ratio when introducing ruthenium at a certain stage of the HAP synthesis. The time of reaching the maximum sorption is greatly affected by the synthesis method for HAP and its HAP—Ru complex. In the case of the precipitation and cocrystallization method, this time is 1 h, and when obtaining HAP by the enzymatic method (HAP_E) using alkaline phosphatase this time is 1 min. This is due to the significantly more developed external and internal surfaces of HAP_E. The sorption binding of ruthenium ions with HAP is almost irreversible. The introduction of ruthenium radionuclides (¹⁰⁶Ru as an example) into similar composites is possible both at the synthesis stage and during sorption, while the isotope exchange does not make a significant contribution to this process.

A series of new polyetherimides (PEIs) based on unsymmetrical 3,4′-(4,4′-(diphenyldioxy)diphthalic anhydride and a number of diamines were synthesized by single-stage high-temperature catalytic polycondensation in molten benzoic acid used as the so-called “active medium”. The chemical structure and phase morphology of the polycondensation products were studied by ¹H NMR and IR spectroscopies and by wide-angle X-ray scattering. The molecular weight characteristics were studied by viscometry and GPC methods. The synthesized PEIs are high-molecular-weight, film-forming, amorphous polymers that are soluble in organic solvents and possess good mechanical properties. The thermal properties of the synthesized PEIs were evaluated by DSC, TMA, and TGA methods. The polymers have high thermal and thermo-oxidative stability (> 500 °C), while their glass transition temperatures lie in the range of 220–300 °C depending on the diamine used in the synthesis. The rheological properties of melts were studied for a number of thermoplastic PEIs.

Studies of the catalytic activity of carbohydrases toward various polysaccharides and the data on the effect of the amino acid residues in the active site or in its vicinity on the activity of enzymes, their thermal stability, the pH optimum of the activity, and the susceptibility to inhibitors confirm the complexity of the spatial arrangement of their active site. The introduction of amino acid substitutions into carbohydrases made it possible to increase the activity of the enzymes, enhance the efficiency of polysaccharide hydrolysis, and increase the thermal stability of the enzymes and their resistance to inhibitors.

The effect of fluorene adsorption on the electronic and optical properties of graphene and MoS₂ monolayers was investigated. The fluorene—graphene and fluorene—molybdenum disulfide binding energies were estimated and the energy band structures and absorption coefficients were calculated using the density functional theory. Specific features of the atomic structure and physicochemical properties of the 2D layers after attachment of fluorene molecules are demonstrated.

Adsorption of poly(ionic liquid) (PIL) poly(1-ethyl-3-vinylimidazolium bromide) onto conductive surfaces was examined by quartz crystal microbalance with dissipation monitoring and atomic force microscopy. High surface coverage and the formation of continuous nanosized films were achieved by increasing the PIL concentration in the solution taken for adsorption of the polymer. The polymer-modified surfaces were used for subsequent electrostatic binding (adsorption) of glucose oxidase (GOx) as the model enzyme. The efficiency of the enzymatic reaction toward glucose for the prepared PIL—GOx thin films was evaluated by amperometry. The amperometric responses of the films correlate well with the efficiency of modification of the native surface by the polymer. Multiparameter physicochemical optimization of the adsorption of PIL and GOx made it possible to demonstrate the application potential of the polymer-enzyme thin films for highly sensitive analysis of glucose.

A new approach to evaluate the stability and integrity of a protein layer coating the surface of magnetic iron oxide nanoparticles (IONPs) in an aqueous medium was described using human serum albumin (HSA) as an example. The approach envisages investigation of the catalytic (peroxidase-like) activity of IONPs characterized by the generation rate of a colored product of o-phenylenediamine oxidation and examination of the capability of IONPs of binding to the plasma protein immunoglobulin G (IgG) to form submicron- and micron-sized aggregates. A correlation between the generation rate of hydroxyl radicals and the integrity of the HSA coating on the IONP surface (confirmed by experiments using IgG) was established for the first time. The approach developed belongs to the methods with a gentle impact on systems (non-damaging and low-damaging methods) for in situ and ex situ applications. The approach provides new possibilities for studying the physicochemical properties of hybrid nanosystems or submicron systems at various steps of their synthesis, as well as near physiological conditions, for example, in the blood plasma.

A convenient one-step synthesis of substituted 1,4-benzoxazepin-2-ones and 1,4-benzodiazepin-2-ones by recyclization of N-arylitaconimides with o-aminophenol and o-phenylenediamines. A detailed analysis of the spectral data of the synthesized compounds unambiguously confirmed the suggested structures. It was demonstrated that 1,4-benzoxazepin-2-ones are more conformationally flexible than 1,4-benzodiazepin-2-ones.