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New biodegradable water/sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/isopropyl myristate (IPM) microemulsion systems for the delivery of medicinal and physiologically active substances are synthesized. The optimum concentrations of components that ensure solubilization of the largest amount of water-soluble substances are selected. The diffusion of model substances (L-lysine, L-serine, glycine, β-alanine) across a membrane is studied. It is found that the rate and pattern of release from the microemulsion vary strongly, depending on the terminal functional groups of amino acids. The effect the hydrophobicity and size of the introduced compounds have on the interaction with components of the transport system is determined using H1 NMR, self-diffusion NMR, the polarized luminescence of laurdan and fluorescein probes, and dynamic light scattering. It is shown that short-chain and polar amino acids are released much more quickly than charged amino acids. The results allow determination of the delivery characteristics of more complex counterparts (e.g., medicinal substances and protein molecules).

In this paper, we analyze reaction processes that occur in laminar flows of a flow focusing microfluidic device. The microfluidic reaction systems that comprise hydroxonium and hydroxyl ions are proposed as the media for evaluating diffusion coefficients of reacting particles. Diffusion coefficients are calculated by comparing the experimental data with the results of mathematical simulations. The diffusion coefficients evaluated with microfluidic chip agree well with the literature data.

The optical and photocatalytic properties of CdS quantum dots doped with manganese ions are considered. The quantum dots were synthesized by the colloidal method in an aqueous medium with mercaptoacetic acid as stabilizer. The optical, dimensional, and paramagnetic properties of the obtained nanoparticles were studied. The photocatalytic properties of the quantum dots were studied in the model degradation of rhodamine B. The effect of the concentration of manganese ions and the temperature of the reaction mixture on the rate of photodegradation of the dye was studied.

Based on the luminescence spectroscopy data, it was shown that the method of fixing (between two plates of quartz, quartz and brass, quartz and silicon) a vitrified film prepared from a powder of an anisometric europium(III) β-diketonate complex does not affect the photophysical properties of the film in the temperature range of 270–370 K and, accordingly, does not affect the operational characteristics of a reusable and highly sensitive luminescent temperature probe based on it.

Optical and magnetic properties of CdS quantum dots (QDs) doped with europium(II) and gadolinium(III) ions were studied. l-Cysteine stabilized nanoparticles were synthesized by the colloidal method in aqueous media. The QDs obtained have a hexagonal crystal lattice. The nanoparticle size varies from 3 to 14 nm. The EPR spectra of nanoparticles prepared in different conditions were measured and analyzed. Dependences of the optical properties of nanoparticles on the reaction time and pH values were studied. The dependence of the luminescence properties of CdS QDs on the dopant ion type was established. It was shown that the increase in the reaction time and medium pH values favors a bathochromic shift of maxima in the luminescence spectra of nanoparticles.

A new approach to the synthesis of luminescent soft media using a terbium β-diketonate complex and substituted p-tert-butylthiacalix[4]arene containing quaternary ammonium fragments with amino acid substituents in the lower rim was developed. The synthesized heteroligand complex was incorporated into the framework of the lyotropic mesophase P123-C2H6O2. The liquid crystal properties of the P123-C2H6O2 binary system were studied and the concentration limits of the complex incorporation into the lyomesophase were determined. The long-period ordered structures of lyomesophases was confirmed by small-angle X-ray scattering measurements. The intermolecular interactions of the system components were estimated by IR spectroscopy. The luminescent properties of lyomesophases including a hetero-ligand macrocyclic complex and a low-molecular-weight analog based on an ionic liquid were analyzed. Enhanced luminescence efficiency was observed for lyomesophases with the macrocyclic complex.

The process of phase formation in solutions of polyacrylic acid and cetyltrimethylammonium bromide was studied in microfluidic channels with a characteristic size of 100–200 µm. The system of convection—diffusion—reaction equations was solved to develop an association model in polyelectrolyte—surfactant solutions in a microchannel with the laminar flow of the reactants. The phase formation conditions in the microchannel volume were considered. The recommendations for control of the phase behavior in the microchannel were proposed, as well as for the design and operation mode of microfluidic devices used for the synthesis of polymer—surfactant complexes and characterization of association in polyelectrolyte—surfactant solutions.

Modified polysaccharides were prepared by the reaction of citrus pectin with a cationic monomer, (1,2-epoxypropyl)triethylammonium chloride, in alkaline medium and under the action of microwave radiation in the reactor system microwave–ultrasonic–UV-induced synthesis. Organic hybrids were prepared by mixing aqueous solutions of natural polysaccharides (pectin and modified pectin with chitosan) under ambient conditions in 1 : 1 ratio. The influence of the concentration of citrus pectin, its modified samples, chitosan, and their organic hybrids on the flocculating properties was studied for a model disperse system, a suspension of titanium dioxide in water and aqueous salt solutions, under the conditions of free (unrestricted) sedimentation. The influence of the ionic strength on the conformational state of polysaccharide macromolecules and on the aggregation of titanium dioxide particles was analyzed.

A new approach to the creation of photostable highly sensitive sensor elements for reusable luminescent thermometers based on vitrified films of mesogenic europium(III) and terbium(III) beta-diketonate complexes that are oxygen insensitive, effectively absorbing light in the region of 390–410 nm and reversibly changing the luminescence decay time in the region of 143–348 K, is proposed.

Arelevant task in the technology of cosmetic and pharmaceutical substances is that of protecting the skin from the harmful influences of ultraviolet light - sunburn, photodermatoses, skin cancerogenesis, and light-induced aging. Gels containing N-(β-hydroxyethyl)-4,6-dimethyldihydropyrimidone-2 (xymedone) and amphiphilic components, i.e., nonionic surface-active substances (surfactants), were developed and studied. Aspectrophotometric method was used to study the selective absorption of xymedone in the UV range. Overall, the structural- mechanical characteristics of gels and assessment of the effects of surfactant on xymedone release processes were used to select the optimum composition for effective protection against light by gels. Studies in models of ultraviolet erythema in albino guinea pigs and volunteers receiving prophylactic applications showed that xymedone-containing gel had photoprotective effects. The presence of a hydroxyethylated higher fatty alcohol in the gel composition with xymedone increased its photoprotective activity.

Novel prospective transport systems are prepared that consist of lyotropic liquid crystals (LLCs), water/sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/isopropyl myristate. The temperature boundaries of phase transitions at different water contents and in the presence of guest molecule L-lysine amino acid and the types of mesophases formed are determined via differential scanning calorimetry (DSC), polarization optical microscopy (POM), and measurements of the wetting angle. It is shown that upon a reduction in the H2O content and the introduction of L-lysine, the thermal stability of a system and the temperature of a phase transition increase, while the mass loss upon heating is diminished. The concentration dependences of thermodynamic properties allow us to control the phase transition temperatures that determine the processes of the controlled release of bioactive molecules from the studied LLC-system.

Biocompatible systems with luminescent properties attract significant interest as they are broadly used in bioanalysis and medical diagnostics. This paper describes new lanthanide liquid crystals based on an oxyethylated amphiphile with a cholesterol fragment (CholEO10). The complex of physicochemical methods (polarizing optical microscopy (POM), X-ray powder diffraction, FTIR-spectroscopy and luminescent analysis) was used to study liquid crystalline, structural and optical properties of these new biomesogens. Their phase behavior was compared with the behavior a lanthanum-containing analogue without a cholesterol fragment in its structure. A rigid hydrophobic fragment was found to exert a strong influence on lyotropic mesomorphism in aqueous media. The phase transition from a lamellar mesophase to a hexagonal one was observed with decrease of the CholEO10/La3+ complex concentration and addition of water. The study of luminescent properties of CholEO10/Ln3+ complexes, where Ln3+ is Dy3+, Tb3+, or Eu3+, revealed that their characteristic emission occurs in the yellow, green and red spectral ranges. Optical characteristics of new mesogens were estimated. Mesogenic CholEO10/Tb3+ and CholEO10/Eu3+ complexes demonstrate longer lifetime of their excited state as compared with the C12EO10/Ln3+/H2O complex.

An analysis of the prospects for creating new luminescent molecular photonics materials based on mesogenic lanthanide(III) β-diketonate complexes is presented. We consider vitrified films that combine intense monochromatic luminescence, high optical quality, and complete resistance to UV radiation with the ability to change their photophysical properties (for example, the absorption band width and luminescence intensity) depending on the local structure and under external actions, such as UV radiation and temperature. The problems of control of the photophysical properties of these films and the possibility of their application as working media of high-tech luminescent materials and devices (for example, luminescent sensors of temperature, oxygen, and UV radiation, as well as light-conversion materials) are discussed.

Experiments on recording the ultrafast optical Kerr effect (OKE) in solution of europium(III) β‑diketonate complexes in toluene at a concentration of 10–2 mol/L showed that the total OKE signal is not a superposition of two contributions, one of which is related to the vibrational–rotational dynamics of toluene molecules, while the other is due to the vibrational–rotational dynamics of the europium(III) complexes. This immediately indicates that the europium(III) complexes essentially change the structure of liquid toluene, which is reflected in the character of an orientational response in picosecond range.

An 18-fold increase in the mean luminescence intensity of Tb3+ ions in a vitrified film of a terbium( III) β-diketonate complex under UV laser radiation in atmospheric oxygen at 300 K was observed. Luminescence and Raman spectroscopy data reveal that the observed effect was caused by photophysical and photochemical processes changing the geometry and structure of the complex.

Isotropic melts of nine metallomesogenic complexes with a smectic-А phase have been studied by the electric birefringence method. Complexes include Dy, Tb, Gd, and Er rare-earth ions, Schiff bases as ligands, and alkyl sulfate or nitric-acid counterions. It has been shown for the first time that both the magnitude and the sign of the electro-optical effect in the isotropic phase for the studied substances are determined by the length of counterions. This means that the dielectric anisotropy of smectic lanthanide complexes can vary widely depending on counterions: it can be positive, negative, or close to zero.

Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 0172—0175, January, 2018.

A TDDFT study of energy transfer processes in luminescence composite materials based on mesogenic europium (III) complexes with substituted β-diketones and Lewis bases and some semiconducting polymers is presented. The calculated energies of the lowest singlet and triplet excited states of ligands and polymers were used to construct the energy level diagrams and indentify the main channels of intramolecular energy transfer. A system of a complex and a polymer, which is most preferable for practical application in optoelectronics, was selected. The simulated data agree well with the experiment.

Phase diagram was obtained for the first time and processes of lecithin self-organization in the water/ propylene glycol/lecithin/Vaseline oil system were examined. Tensiometric data were used to find the optimal composition of the components, necessary for providing the stability of this system. Specific features of the microemulsion–liquid crystal structural-phase transition were examined. It was shown that both the packing type of molecules and the type of distribution of dispersed-phase particles change in this transition. The systems under study are promising for delivery of medicinal and biologically active substances into cells.

Modified polysaccharide was synthesized by the reaction of amylopectin with a cationic monomer, (1,2-epoxyprop-3-yl)triethylammonium chloride, in alkaline solution in the presence of Fenton’s reagent. The influence of the concentrations of amylopectin, gelatin, their polymer-inorganic hybrids, and modified pectin on their flocculating properties in free (unrestricted) sedimentation of ocher suspension as a model disperse system was studied. Amylopectin exerts a stabilizing effect, whereas the modified pectin and polymer-inorganic hybrid exert a flocculating effect. The influence of the mode of introducing polymer additives on the flocculating effect and aggregation of ocher particles was analyzed.

The permittivity components of the liquid crystalline gadolinium complex with Lewis bases and β-diketonates as ligands are measured in the frequency range from 100 Hz to 5 MHz. The magnitude and sign of the dielectric anisotropy of the complex are determined. Two dispersion regions of the permittivities are found in the liquid crystalline phase. The mechanisms responsible for the relaxation phenomena occurring in the sample are established. The dielectric relaxation times, activation energies, and dipole moment of the complex are obtained. The results of the study are compared with the dielectric properties of ytterbium and terbium complexes having the same ligand environment.

The adhesive interaction of some polymer surfaces with neutral, acidic, and basic samples formed on a cantilever specimen has been evaluated via atomic-force microscopy. The thermodynamic work of adhesion has been calculated using the Johnson–Kendall–Roberts model. The differences in the work of adhesion values obtained in the interaction of acidic, basic, and neutral samples with the same polymer surface have been found. The experimentally obtained values of work of adhesion have been carefully compared with theoretically calculated ones, which allowed the conclusion to be drawn that the area of research under consideration is promising.

Measurements of the refractive indices and optical anisotropy of a series of liquid crystalline coordination compounds based on lanthanides with an identical ligand environment have been carried out. It was found that the magnitude of the optical anisotropy of the investigated complexes was several times smaller than the anisotropy of organic liquid crystals. Analysis of the results showed that the variation of the ion complexing agent had little effect on the magnitude of the optical anisotropy in the mesogenic complexes containing the same ligands. The even-odd alternation of the optical anisotropy of lanthanidomesogens at the increasing the number of protons in the ions of the lanthanides has been observed.

Atomic force microscopy (AFM) has been used to study forces of intermolecular interactions in two different types of liquid crystal (LC) systems (thermotropic and lanthanide-containing lyotropic ones) with different supramolecular organization and degrees of surface hydrophilization in relation to self-associated silane monolayers on a cantilever probe. Statistical analysis has been applied to the force curves to determine adhesion between liquid crystals and monoassociated layers of trichlorododecylsilane and (3-mercaptopropyl)trimethoxysilane on silicon. The results have been analyzed within the framework of hydrophilic and hydrophobic interactions and compared to the free surface energy values calculated by the Owens, Wendt, Rabel and Kaelble method. Lanthanide-containing liquid crystals demonstrate high value of adhesion work to monoassociated silane monolayers due to their considerable free surface energy. The method of chemical force microscopy (CFM) is found to be applicable to the direct determination of the adhesion force of liquid crystals.

The effect of boundaries on the nematic–isotropic phase transition temperature in a melt of a metallomesogenic complex was studied for the first time. This was done by comparison of the electro-optical constant of the isotropic phase with the dielectric and optical anisotropy of the nematic phase on the basis of the Landau–de Gennes theory. In a real experiment, the two liquid phases (nematic and isotropic ones) coexist in a range of several degrees around the transition. According to polarization microscopy data, the phase transition temperature decreases by more than 10°C as the metallomesogen layer thickness is reduced from 200 to 5 μm.

Multilayer systems consisting of layers of hybrid quantum dots are fabricated. The quantum dots with the CdSe/CdS core/shell structure are chemically synthesized and deposited on the surface of quartz glass that contains ion-synthesized silver nanoparticles in the near-surface region. Silver nanoparticles exhibit optical absorption owing to the localized surface plasmon resonance. Variations in the photoluminescence intensity of the layer related to an increase in the distance from the quartz surface with metal nanoparticles are studied. An increase in the photoluminescence intensity is observed under excitation in the spectral region of the plasmon absorption of silver nanoparticles. An optimal distance between the layers is determined to maximize the enhancement of the photoluminescence of quantum dots in the presence of the near field of metal nanoparticles.