N. A. Markova

Design of a hybrid nanostructure based on fullerene C60 and biologically active substance for modeling physiological properties of compounds

The effects of cognitive-stimulating substance BD-2 of the γ-carboline family and a hybrid compound based on fullerene C60 and attached BD-2 on various aspects of the behavior of animals were studied. The synthesized hybrid fullerene compound (HFC) has no side psychostimulating effect characteristic of BD-2 but fully retains the properties of a cognitive-stimulating agent. The design of hybrid compounds based on fullerene C60 and pharmacologically active groups can be one of the ways for optimizing therapeutically promising compounds.

Modification of rhodium carbonyl catalysts for hydroformylation of 2-butenes by organophosphorus ligands

The influence of the nature of the organophosphorus ligand and the P/Rh molar ratio on the catalytic properties of rhodium carbonyl complexes in hydroformylation of 2-butenes was studied. The difference between phosphine and phosphite ligands during the formation of highly selective catalytic complexes was found. It was supposed that a decrease in the selectivity with respect to 2-methylbutanal is due to the isomerization of olefins under conditions of a decrease in the competitive capability of CO for coordination sites (the high P/Rh ratio, a decrease in the total pressure of the synthesis-gas).

Carbonylation of methyl acetate in the presence of polymeric rhodium-containing catalysts

New catalytic systems based on RhCl3 and polymeric nitrogen- and oxygen-containing supports were proposed for the carbonylation of methyl acetate to acetic anhydride. The catalytic systems possess a high activity typical of homogeneous catalysts. The high activity is retained upon the repeated use of the catalyst separated from the reaction products. The nitrogen-containing polymers of the chitosan type serve as cocatalysts. In their presence, the induction period disappears, and the catalytically active species are stabilized, thus enabling the replacement of expensive LiI for cheaper salts of this metal.

Isobutene hydroformylation in catalytic systems based on rhodium compounds and polyelectrolytes

The catalytic properties of water-soluble systems based on rhodium complexes and polyelectrolytes in isobutene hydroformylation were studied. All of the catalytic systems exhibited an unexpectedly high activity under the conditions where homogeneous hydroformylation virtually did not occur in the presence of conventional rhodium catalysts. A stable catalytic system based on acacRh(CO)2-PEG complex was proposed, allowing isobutene hydroformylation to be performed with a high activity under mild conditions.

Transformation of rhodium carbonyl complexes in hydroformylation of 1-hexene studied fromin situ IR spectroscopic data

Rhodium carbonyl complexes that formed from RhCl3·4H2O and RhCl3·4H2O modified by poly-N,N-dimethyl-N,N-diallylammonium chloride in a methanol—chloroform medium in the hydroformylation of 1-hexene were studied byin situ IR spectroscopy. Along with the rhodium hydrocarbonyl complexes, anionic complexes of the [Rh(CO)2Cl2]− type, whose concentrations and rates of formation in an acidic medium are much higher than those in a basic medium, were shown to be the active centers of hydroformylation. The function of the polycation is the stabilization of the catalytically active mononuclear rhodium complexes.

Effect of composition of the aqueous phase on catalytic properties of RhCl3 modified with a polycation in hydroformylation of 1-hexene

Water-soluble catalytic systems based on RhCl3 and the salts of polycations (poly-N,N-diallyl-N,N-dimethylammonium chloride and poly-N,N-diallyl-N-methylaminodihydrophosphate) have been studied. It has been established that the rate of hydroformylation of 1-hexene increases with increasing pH of the aqueous phase. The replacement of the alkyl group at the nitrogen atom with the hydrogen atom in a polycation makes it possible to form a stable catalytic system at pH ≥5. The addition of low molecular electrolytes (NaCl, Na2SO4, and NaPO4) also affects the catalytic properties of the studied catalytic systems. Stability of a catalytic system is enhanced with increasing charge of an anion of a low molecular electrolyte, which is, apparently, due to formation of intra- and intermolecular bonds in polyelectrolytes.

Hydroformylation of olefins in the presence of rhodium carbonyl catalysts immobilized on polymeric pyrrolidinopyridines

The hydroformylation of olefins in the presence of catalytic systems based on RhCl3 and polymeric pyrrolidinopyridines was studied. lt was shown that the catalytic system has high activity in the hydroformylation of isobutylene under conditions when the activity of conventional homogeneous catalysts is low. The polymeric catalysts are also thermostable. The effect of solvents on the catalytic properties of the system was studied.

SELECTIVITY OF CATALYTIC SYSTEMS RHCL3.POLYCATION IN HYDROFORMYLATION OF HEX-1-ENE UNDER CONDITIONS OF BIPHASE CATALYSIS

Approaches to increasing the selectivity of water-soluble catalytic systems based on RhCl3 and polycation in hydroformylation of hex- 1-ene were studied. The introduction of a long-chain alkyl radical into the polycation or the use of a higher fatty acid anion results in an increase in the selectivity of the catalytic system at pH > 7 with respect to n-aldehyde to 60 %. This effect is presumably associated with the suppression of isomerization processes due to steric hindrances.

31P NMR study of the hydrolytic activity of ethriol phosphite and triphenyl phosphite in a two-phase system

The hydrolytic activity of ethriol phosphite and triphenyl phosphite in the p-xylene/water two-phase system was studied by the31P NMR method. It was shown that the rate of hydrolysis can be controlled by varying the pH of the aqueous phase. Hydrolysis of triphenyl phosphite is much slower than that of ethriol phosphite in the tested pH range. Coordination of ethriol phosphite with a rhodium carbonyl complex completely suppresses its hydrolysis.