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The gas chromatographic properties of the porous methacrylate polymers, copolymers of 2,3-epoxypropyl methacrylate (2,3-EPMA) and ethylenedimethacrylate (EDMA), modified by silver nanoparticles were studied. The modification of the initial methacrylate copolymer by silver nanoparticles almost does not change the ability of the copolymer to dispersion interaction but results in an increase in polarity and enhances the possibility of specific interactions to occur. The aminated copolymer (copolymer of 2,3-EPMA and EDMA modified by diethylenetriamine using the reaction at the epoxy group) modified by silver nanoparticles demonstrates a higher ability to dispersion interactions and a lower polarity. Possibly, the sorption of silver particles on amino groups of the polymer is a reason for decreasing polarity of the polymer.

The paper addresses the effect of a new fatty acid elongase 6 (ELOVL6) inhibitor on the migration of breast cancer cells (estrogen receptor positive MCF7 cells and estrogen receptor negative MDA-MB-231 cells) and expression of genes associated with the epithelial-mesenchymal transition, the first stage of tumor metastasis. It was shown that inhibition of the synthesis of C18 fatty acids does not change the migration activity or expression of transcription factors regulating the epithelial-mesenchymal transition. At the same time, the inhibition of ELOVL6 resulted in overexpression of genes associated with breast cancer development and metastasis in vivo (EGFR, CASP4 and VEGFA).

Approaches that allow one to carry out quantitative analysis of real objects, solutions of nitric acid after contact with sorbents based on N,N,N′,N′-tetra-n-octyldiglycolamide (TODGA), by MALDI mass spectrometry are considered. The internal standard for the quantitative determination of the target component in real samples containing a high excess of inorganic salts is selected. It is found out that reproducible results can be obtained by the external standard method for a large sampling of experimental data, but the internal standard method can significantly improve the accuracy of quantitative analysis. The use of the internal standard makes it possible to eliminate an inaccuracy related to nonuniformity of sample preparation.

Electrospray ionization chromatography-mass spectrometry was used to study transarylation and disproportionation reactions of di(4-methoxyphenyl) and di(4-dimethylaminophenyl) telluroxides in refluxing toluene. The reaction mixture compositions were established based on the mass spectrometry data and relative retention times. General schemes for fragmentation of the reaction mixture components were suggested.

The retention of peptides with protected functional groups on the Hypercarb carbon sorbent was studied by reversed phase HPLC. The peptides were identified by tandem mass spectrometry with electrospray ionization. The thermodynamic characteristics of adsorption (TCA) of the peptides on the graphitized thermal carbon black were determined by the molecular statistical method and compared with the retention values obtained by liquid chromatography on the Hypercarb carbon sorbent. Relationships between the calculated values of TCA and experimental retention values were shown.

N,N´-Bis(2-bromobenzyl) diaza-15-crown-5 and -diaza-18-crown-6 ethers were obtained in high yields. Palladium-catalyzed amination of these compounds with equimolar amounts of linear polyamines and oxadiamines afforded a large number of macrobicyclic compounds. It was found that the structure of starting compounds is crucial for the formation of the target cryptands and that their yields can substantially be increased by using larger catalyst loadings.

Pd(0)-catalyzed N,N-diarylation of [2-(1-adamantyloxy)ethyl]amine and (2-methoxyethyl)amine with 2,7-dibromonaphthalene and 4,4′-dibromobiphenyl was studied. The diarylated derivatives synthesized were involved in the catalytic macrocyclization with oxadiamines and tetraamine to give macrocycles containing one polyamine fragment in the case of naphthalene-containing derivatives and two polyamine moieties in the case of biphenyl-containing derivative. The yields of the products were found to depend on the structure of the starting compounds.

N-(3,5-Dibromobenzyl) derivatives of 1-aza-15-crown-5 and 1-aza-18-crown-6 were synthesized in high yields and their palladium-catalyzed amination reactions with various linear polyamines were studied. As a result, macrobicyclic compounds were obtained in yields up to 56%. The complexation of some macrocycles with zinc and cadmium nitrates was studied by NMR titration.

Alkyl isothiocyanates were proposed for the determination of 1, 1-dimethylhydrazine (DMH) in the form of 4-alkyl-l, l-dimethylthiosemicarbazides by gas chromatography coupled with mass spectrometry (GC-MS). 4-Alkyl-l, l-dimethylthiosemicarbazides are selectively formed under mild conditions in the absence of catalysts. During the chromatography, these thiosemicarbazides are efficiently resolved from excess of alkyl isothiocyanates. A possibility of identification of DMH derivatives on the basis of the chromatographic retention parameters and fragmentation data under electron ionization conditions was demonstrated.

Thermodynamic characteristics of adsorption (TCA) for six-membered aromatic nitrogen-containing heterocycles (azines), viz., pyridine, pyridazine, pyrimidine, and 1,3,5-triazine, on graphitized thermal carbon black (GTC) were experimentally determined and theoretically calculated. The best coincidence of the experiment and calculation is achieved using atom-atomic potential functions of intermolecular interactions, which allow for a decreased π-electron density in the aromatic system. The N atoms in the azine molecules are nonequivalent in terms of the adsorption behavior. The GTC surface very selectively adsorbs azines with different molecular structures, and this selectivity can be used for separation and chromatographic analysis of these compounds. The dependence of TCA of azines on the degree of aromaticity of their molecules has been established for the first time.

Thermal desorption and thermodestruction of modifiers (short- and long-chain aliphatic carboxylic acids, synthetic butadiene and nitrile rubbers with end carboxyl groups) were studied by thermal desorption mass spectrometry. The results obtained were compared with the thermal stability of individual modifiers. It was shown that the use of dispersed aluminum as a filler decreases the thermal stability of compositions based on butadiene and nitrile rubbers.

Thermodynamic characteristics of adsorption of some isomeric aminoadamantanes on graphitized thermal carbon black were determined by molecular-statistic calculations and gas-chromatographic measurements. The parameters of the potential function for the pairwise intermolecular interactions between nitrogen in saturated amines and carbon in graphite were calculated. The best agreement between the experimental and calculated Henry constants for 1-aminoadamantane is attained by introducting a correction taking into account the influence of the “cage” effect on α-substituents in the adamantane unit in the parameters of the ϕN...C(GTCB) atom-atom potential.

The main thermodynamic characteristics of the adsorption of haloadamantanes on graphitized thermal carbon black were determined by experimental measurements and by calculations in terms of molecular-statistic theory of adsorption. Using experimental data, the Kovac retention indices were calculated and the optimum conditions for gas-chromatographic separation of haloadamantanes on stationary phases with different polarity were elucidated. The influence of the “cage” effect in the adamantane unit on the chromatographic properties of haloadamantanes was established.

The thermodynamic characteristics of adsorption of some adamantanol isomers on graphitized thermal carbon black were calculated and determined experimentally. The parameters of the potential function for the intermolecular interaction between hydroxyl oxygen and carbon of the graphite basis plane were determined for the first time. The adsorption properties of adamantanols are largely determined by electron density distribution in the adamantane cage, which are related to the “cage” effect.

Nonequivalence of the nodal and bridging carbon atoms of the adamantane molecule during adsorption on graphitized thermal carbon black was shown. The nonequivalence is related to a special type of intermolecular interaction, the cell effect. Based on the experimental data and the molecular statistical calculations of Henry's constants, the parameters of atomatom potentials for the nodal carbon atoms in the adamantane molecule were found. This atom-atom potential differs from that known for the carbon atom in the sp3-hybridization.

Different methods of introducing correction factors into parameters of atom-atom potentials of intermolecular interaction used for calculation of thermodynamic characteristics of adsorption by the semiempirical molecular statistical theory were compared. A method of isostructural fragments based on the application of the atom-atom potential corrected for the molecular fragment was suggested for introducing the correction factors. The advantages of this method were demonstrated for chlorobenzenes, chlorodioxines, and chlorobiphenyls.

The adsorption equilibrium constants for adamantane, 1-fluoro-, 1-chloro-, 1,3-difluoro-, 1,3-dichloro-, 1,3-dibromo-, and 1-hydroxyadamantane, and methyl 1-adamantyl ketone were determined by gas chromatography. The results were compared with molecular statistical calculations based on the known atomic-atomic potentials of the interaction of atoms of the sorbate molecule with the C atom of graphitized thermal carbon black (GTCB). The experimental adsorption heats exceed the calculated values by 3-10 kJ mol-1. The reasons for this divergence are discussed. The changes in the adsorption entropy show that the molecules of the studied compounds form a layer of the ideal dimeric gas on the GTCB surface upon adsorption.

Henry's constants and the heats of adsorption of isomeric chloronaphthalenes on graphitized thermal carbon black were calculated by the semiempirical molecular statistical method. The calculated data were compared with experimental results. The best agreement was achieved when corrections for the interaction of the Cl atom with the C atom of the adjacent benzene ring and the presence of other Cl atoms inortho-positions are introduced in calculations of the atom-atomic potential.

Henry's constants and the heats of adsorption of benzene chloro derivatives on graphitized thermal carbon black were calculated by the semiempirical molecular statistical theory of adsorption. The best agreement between the experimental and calculated data was achieved by introducing corrections for the presence of other chlorine atoms in theortho-positions into the calculation of the atom-atomic potential of the intermolecular interaction of the chlorine atom with the carbon atom of graphite.

The separation and identification of isomers in mixtures of them is a complex problem because of the similarity of their physicochemical properties. It has been shown in the present study that the combined application of chromato-mass spectroscopy and molecular statistical calculations makes it possible to obtain a complete identification of the components in a mixture of isomers. The advantages of a simultaneous application of the two methods are illustrated for mixtures of chlorophenylcyclopropanes and of chlorodiphenyls.

1. As for chlorobenzenes, in the case of bromobenzenes the values of k1 can only be described with one potential ϕ C... Br for bromobenzenes containing no Br atoms in the ortho position if the molecules of the bromobenzenes are considered planar. 2. The best agreement of the experimental and calculated values of K1 for ortho-substituted chloro- and bromobenzenes can be obtained with combined consideration of the effects of a change in the polarizability and deviation of the ortho-positioned chlorine and bromine atoms from the plane of the benzene ring.

Initial heats of adsorption of a number of halomethanes on graphite have been calculated by a semiempirical molecular-statistical method and from the proportionality of the heat of adsorption to critical parameters of the adsorbate. The results from these calculations are in satisfactory agreement with each other and with the available experimental data.

At low (zero) occupancies, the thermodynamic characteristics for the adsorption of fluorobenzenes and fluorotoluenes may be calculated using the semiempirical statisticalmechanical theory.