The interest in magnesium-based materials is promoted by their biocompatibility, their bioresorbability, and their recently discovered antibacterial potential. Until now, the widespread use of magnesium alloys in different corrosive environments was inhibited by their weakly controllable degradation rate and poorly understood microbiologically induced corrosion behavior. To better understand the degradation and usability of magnesium-based alloys, in this study we have fabricated superhydrophobic coatings on a magnesium-based alloy, and analyzed the behavior of this alloy in bacterial dispersions of Pseudomonas aeruginosa and Klebsiella pneumoniae cells in phosphate-buffered saline. It was shown that the immersion of such coatings in bacterial dispersions causes notable changes in the morphology of the samples, dependent on the bacterial dispersion composition and the type of bacterial strain. The interaction of the superhydrophobic coatings with the bacterial dispersion caused the formation of biofilms and sodium polyphosphate films, which provided enhanced barrier properties in magnesium dissolution and hence in dispersion medium alkalization, eventually leading to the inhibition of magnesium substrate degradation. The electrochemical data obtained for superhydrophobic samples in continuous contact with corrosive bacterial dispersions for 48 h indicated a high level of anticorrosion protection.

A series of easy-to-prepare and modular chiral bisdiamidophosphites with oxalamide linkers were synthesized. The structures of the novel ligands were elucidated by means of 2D-NMR and confirmed by single-crystal X-ray diffraction. The reactions of such ligands with [Pd(Cod)Cl₂] at molar ratios of L/Pd = 1 and 0.5 were studied by ¹H, ¹³C, ¹³C DEPT, ³¹P, ¹H–¹³C HSQC, ¹H–¹³C HMBC, ¹H–¹H COSY, ¹H–¹H ROESY, ¹H–¹⁵N HMBC and DOSY spectroscopy, as well as by DFT calculations. Stereoselectors of this type exhibited high enantioselectivities in the Pd-catalyzed allylic substitution reactions of (E)-1,3-diphenylallyl acetate with pTolSO₂Na (up to 92% ee), CH₂(CO₂Me)₂ (up to 97% ee), (CH₂)₄NH (up to 96% ee), (EtO)₂P(O)CH₂NH₂ (up to 96% ee) and (CH₂)₄N(CCH(CH₂)₄) (up to 92% ee). ee values of up to 90%, 97% and 83% were obtained in the Pd-mediated allylic alkylation of cinnamyl acetate with ethyl 2-oxocyclohexane-1-carboxylate, allylic amination of cyclohex-2-en-1-yl ethyl carbonate with dibenzylamine and desymmetrization of N,N’-ditosyl-meso-cyclopent-4-ene-1,3-diol biscarbamate, respectively. In addition, ee values of up to >99% were achieved in the Rh-catalyzed asymmetric hydrogenation of methyl esters of unsaturated acids.

In this study, we applied the method of nanosecond laser treatment for the fabrication of superhydrophobic and superhydrophilic magnesium-based surfaces with hierarchical roughness when the surface microrelief is evenly decorated by MgO nanoparticles. The comparative to the bare sample behavior of such surfaces with extreme wettability in contact with dispersions of bacteria cells Pseudomonas aeruginosa and Klebsiella pneumoniae in phosphate buffered saline (PBS) was studied. To characterize the bactericidal activity of magnesium samples with different wettability immersed into a bacterial dispersion, we determined the time variation of the planktonic bacterial titer in the dispersion. To explore the anti-bacterial mechanisms of the magnesium substrates, a set of experimental studies on the evolution of the magnesium ion concentration in liquid, pH of the dispersion medium, surface morphology, composition, and wettability was performed. The obtained data made it possible to reveal two mechanisms that, in combination, play a key role in the bacterial decontamination of the liquid. These are the alkalization of the dispersion medium and the collection of bacterial cells by microrods growing on the surface as a result of the interaction of magnesium with the components of the buffer solution.

The article describes a comprehensive mass spectrometric approach to the study of surfaces of structural materials. The combined use of thermal desorption mass spectrometry, gas and liquid chromatography, and laser desorption/ionization mass spectrometry (LDI) to provide information about the surface and surface layers of materials is proposed. The suggested method allows one to determine the thermodynamic characteristics of compounds and surface contaminants adsorbed on surfaces, as well as surface layers, to determine the composition of volatile and non-volatile contaminants on the surface, and to determine the nature of the distribution over the surface of these compounds. The method allows to obtain the most complete information about the surface condition and can be used to predict the life of structural materials.

Examples of cluster formation from inorganic and organic compounds upon surface-assisted laser desorption/ionization have been considered. It has been shown that the cluster formation is especially...

The stabilities of silver clusters with organic and inorganic anions on carbon and metallic surfaces are compared. It was revealed that inorganic anions, primarily halides, stabilize the clusters more effectively than anions of amino acids do. A possible practical application of the cluster stabilization technique was demonstrated for investigation of surface morphology and determination of trace amounts of amino acids. The homogeneity of the morphology of Ad-0 and AMg-6 alloys on the distribution of cluster-forming compounds on the surface was investigated. It was shown that the distribution of silver chloride on the surface after exposure to an aggressive medium was less uniform than on a surface that was in an inert atmosphere. A method is proposed for identifying trace amounts of amino acids on the surfaces of these alloys with the use of a clustering salt of silver chloride, which causes ionization of the formation of the adduct of the amino acid with silver, as well as adducts of dimers and trimers of amino acids with alkali metals and salts that increase the reliability of determination. The sensitivity of determination of amino acids by this method increases up to ten times.