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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).

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.

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.

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.

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.

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.

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 complexing of protonated chitosan with dodecyl sulfate ions in water solutions is studied using IR spectroscopy data and quantum-chemical calculations. It is established that the electrostatic interaction between the protonated amino groups of chitosan and dodecyl sulfate ions is apparent in the IR spectrum as a band at 833 cm−1. The need to consider the effect the solvent has on the formation of hydrogen-bound ion pairs [CTS+ ⋅ C12H25O3-] is shown via a quantum-chemical simulation of the equilibrium geometry and the energy characteristics of complexing and hydration.

Hybrid liquid crystal systems with different ratios of the components have been prepared on the basis of 5,5′-di(heptadecyl)-2,2′-bipyridine tris(β-diketonate) lanthanum(III), europium(III), and terbium(III) complexes, and their liquid crystalline and luminescence properties have been studied. A relation has been found between the luminescence intensity and concentration of the components, and a probable mechanism of photoexcitation in the hybrid systems has been proposed.

The processes of dispersing carbon nanotubes in interfacial and adhesive compositions for producing modified polymer aramid papers in the presence of nonionic surfactants—ethylene oxide derivatives-have been studied. Optimum surfactant concentrations for the more effective disintegration of carbon nanotubes have been found. Quality-control methods of the distribution of the nanomodifiers in the composite surface layer have been developed. Prepreg samples with the improved physical and mechanical properties for application in aviation have been prepared.

Luminescent properties of liquid-crystalline tris(β-diketonate) europium(III) complexes with Lewis bases (substituted 2,2′-bipyridine and 1,10-phenantroline) are investigated. Absolute and relative quantum yields and lifetimes are determined. Absorption, excitation, and emission spectra of the complexes are investigated.

The kinetics of free and hindered sedimentation of a suspension of titanium dioxide (anatase) under the action of a high-molecular-weight cationic acrylamide copolymer and of hybrid polymer-inorganic nanosystems was studied. The influence of the content of the cationic acrylamide copolymer in hybrid systems and of the particle size on the TiO2 aggregation in gravity and centrifugal force fields was analyzed.

Dispersion of C60 fullerenes in water and ethanol in the presence of nonionic surfactants, ethylene oxide derivatives, was studied. It was found that the quality of the dispersion process and the stability of dispersions depend on the structure, degree of oxyethylation, and concentration of surfactants. The optimal conditions are found in which stable fullerene dispersions are obtained as ingredients of cosmetic preparations with antioxidant properties.

The review concerns liquid-crystalline mono- and disubstituted ferrocenes, systems based on ferrocenophane, heteronuclear complexes with ferrocene-containing ligands, ferrocene-based polymers and dendrimers, as well as mixed systems based on ferrocene derivatives. It is shown that liquid-crystalline ferrocene exhibits unique physical properties. The state of the art in the title field and prospects for the development of research on such liquid crystals are outlined and the present and possible fields of their application are discussed. The bibliography includes 131 references.

Results of X-ray diffraction (XRD), absorption spectra, and photoluminescence emission spectra are presented for CdS nanoparticles prepared by different techniques. These techniques included preparation of CdS nanoparticles in a liquid crystal state with H2S as well as by mixing two lamellar phases, sol-gel technique, using thiophenol as capping agent, and prepared it in reverse micelles. XRD, which shows the crystalline nature of the materials as well as determines their size with Scherrer's equation has been studied. Absorption spectra, not only for CdS nanoparticles but for CdS dispersed in polymethylmethacrylate (PMMA), were studied and show a blue shift as a result of nanoparticles. Also, the photoluminescence emission spectra for as-prepared nanocomposite CdS that have different peaks depending on different parameters are discussed as will as nonlinear properties through two-photon absorption and second-harmonic generation for the prepared samples.

A series of new β-diketones containing in their structure cyclohexane and benzene ring was obtained. The effect of the terminal substituents in the molecules of β-diketones on their liquid crystal and optical properties was studied. The absorption spectra of all β-diketones practically do not overlap with the emission spectrum of polymer PFO but have good overlapping with that of PVC. The obtained compounds are promising ligands for synthesis of liquid crystal adducts of lanthanide β-diketonates with the Lewis bases, polyfunctional luminescent materials.

The results of the synthesis and characteristics of the new lyotropic lanthanide-containing liquid-crystalline systems possessing the nematic phase based on the zwitterionic surfactant, N,N-dimethyldodecylamine oxide (C12DMAO), in the aqueous-decanol environment are presented. The phase diagrams are constructed. The formation of the La-O coordination bonds in the liquid-crystalline complex C12DMAO/LaIII is confirmed by IR spectroscopy.

The phase behavior of a self-organizing system based on the nonionic surfactant of decaethylene glycol monodecyl ether-lanthanum nitrate hexahydrate-water and decanol is presented. A system phase diagram was constructed. The concentration, temperature ranges of existence and types of liquid crystal phases were established. Analysis of structural changes during the phase transitions hexagonal phase-lamellar phase-isotropic liquid was made on the basis of data obtained by viscosimetry and self-diffusion NMR.

The structural analog of liquid-crystalline adducts of lanthanides containing nitroxyl radicals in the bipyridine moiety was synthesized. The distances between the radicals in the ligand and adduct were determined by the pulse ESR technique. The obtained data were used as a criterion for the adequate choice of the parameters of the semiempirical quantum chemical calculation of the structures of the LnIII coordination compounds containing paramagnetic centers.

Molecular self-organization in a system based on lanthanum nitrate and the nonionogenic surfactant, viz., decaethylene glycol monododecyl ether, was studied in an aqueous solution and in the liquid-crystalline state. Molecular motion and phase transitions in the system were characterized by the high-resolution pulsed gradient spin-echo 1H NMR method.

Lanthanide tris(β-diketonates) were used as ionophores for plasticized polymer membranes of ion-selective electrodes. Electrochemical properties of the membranes were characterized, and the possibility of their use as components of chloride ion-selective electrodes was studied.

Liquid crystalline lanthanide complexes with N-aryl-substituted β-aminovinyl ketones were synthesized for the first time. The complexes give rise to smectic A mesophase and are stable only in the solid state; in going to solution, they dissociate with formation of the initial ligand.

By methods of conductivity measurements, micellization of sodium dodecyl sulfate in ethylene glycol at the concentration above 0.18 M is shown. The La 3+ ion catalysis of solvolysis of phosphorus acid ester both in the absence of surfactant and in the micellar sodium dodecyl sulfate solution in ethylene glycol is found. The influence of the other lanthanide ions on the kinetics is also studied. The La 3+ and Pr 3+ are found to exert an identical effect while Sm 3+ is less effective. By methods of polarizing microscopy, the formation of liquid crystalline mesophase at high lanthanum (tris(dodecyl)sulfate concentrations in ethylene glycol is revealed. The investigation of the catalytic effect of the sodium dodecyl sulfate -La 3+ (3 : 1 molar) composition has shown a sharp acceleration of the reaction at high surfactant concentration.

Electronic and ESR spectroscopy was used to show that the reactions of dimethylaminomethylcalix[4]resorcinarene with Cu(II) salicylaldiminates bearing alkyl substituents at the salicylaldiminate nitrogen atom give 1 : 1 adducts with the dimethylamino group coordinated axially to the Cu(II) complex. The spatially organized calix[4]resorcinarene structure and the possibility of outer-sphere interactions favor a much higher stability of the adduct compared with the similar complex with 2-dimethylaminomethylphenol. In going from alkyl to aryl substituents, salicylaldiminates are replaced by the anion derived from dimethylaminomethylcalix[4]resocinarene. The same replacement takes place in the reaction with 2-dimethylaminomethylphenol.

Nanoparticles of CdS were isolated by the treatment of thereaction mixture followed by the precipitation of CdS ina centrifuge, and the precipitate was washed with ether.Nanoparticles of CdS in pyridine were mixed in an ultrasonic stirrer with poly(methyl methacrylate) (PMMA) inan amount of 7% of the polymer weight. Then the suspension obtained was poured on a quartz support and dried at60 °C. The resultant sample was a film 0.3 mm thick. Theabsorption spectrum of the nanocomposite СdS—PMMAexhibits a shift to the blue region compared to that ofa single crystal of CdS. This shift is due to the quantumdimensional effect characteristic of nanoparticles of semiconductor crystals.

Mesogenic complexes were synthesized by the reaction of β-aminovinyl ketones with copper(ii) acetate. On going from the ligands to complexes, the temperature of phase transitions increases and the nematic phase disappears. The initial members of the homological 1-(4-nonyloxyphenyl)-3-(4-methoxyphenylamino)-1-propen-1-one series demonstrate the alternation of clearing temperatures, which is absent for the corresponding copper(ii) complexes.

We have synthesised liquid-crystalline rare-earth complexes with Schiff base ligands. The stoichiometry of these complexes is Ln(LH)(3)(NO3)(3), where Ln is a trivalent rare-earth ion (Y3+, La3+-Lu3+, except Ce3+ and Pm3+), LH is the protonated form of the Schiff base 4-alkoxy-N-octadecyl-2-hydroxybenzaldimine. The mesophases were studied by optical microscopy and by differential scanning calorimetry (DSC). For the complexes with the 4-octyloxy-N-octadecyl-2-hydroxybenzaldimine ligand, a gradual increase in the melting point and a gradual decrease in the clearing point is found when going from La3+ to Lu3+. In this way, the mesophase range narrows over the lanthanide series. This is due to the lanthanide contraction. The textures observed by optical microscopy reveal the presence of a smectic A mesophase. ispartof: Chemical Physics Letters vol:300 issue:3 pages:509-514 status: published

Boron difluoride β-diketonate exhibiting liquid crystalline as well as photoluminescence properties was prepared for the first time. It is the promising material for creating supramolecular organized luminescent media.

A new series of liquid-crystalline Schiff base lanthanide compounds of the general formula (L{sup {double_prime}}H){sub 2}L{sup {double_prime}}MX{sub 2} was prepared (L{sup {double_prime}}H = H{sub 2n+1}C{sub n}OC{sub 6}H{sub 3}(OH)CHNC{sub m}H{sub 2m+1}; n = 7, 12; m = 14, 18; M =La, Tb, Dy, Er, Nd, Ho, Eu, Pr, and Gd; X = NO{sub 3} or Cl). The thermal behavior of these complexes was examined by polarizing microscopy, differential scanning calorimetry, and X-ray diffraction experiments. The ligands L {sup {double_prime}}H are nonmesomorphic, but all lanthanide complexes show smectic A mesophases. Further, temperature-dependent magnetic susceptibility measurements were carried out in order to obtain information about the magnetic anisotropy of the lanthanide compounds. The Tb(III) and Dy(III) derivatives could be oriented by a magnetic field. These liquid-crystalline lanthanide complexes display magnetic anisotropies which are two orders of magnitude greater than those of known liquid crystals. 23 refs., 8 figs., 4 tabs.

In this contribution, magnetic investigations on materials, which essentially combine mesogenic and polymeric properties, were presented. In the glassy and the smectic phase of a copper(II) containing polymer we observed remarkable antiferromagnetic exchange interactions between the copper centers, whereas in the isotropic phase, the magnetism followed the Curie-Weiss law. The monomeric model compound showed Curie-Weiss behaviour. In addition, we describe the magnetic behaviour of mesogenic compounds, resulting from the incorporation of rare-earth ions in chelating units of the liquid-crystalline Schiff base polymer.

A series of liquid-crystalline ferrocene derivatives, Fe{C5H4-C(CH3)=N-N=CH-C6H3(X)-OOC-C6H4-OCnH2n+1}2 (X = H, OH;n = 3 to 12), were obtained by the condensation of 1,1 ′-bishydrazondiacetylferrocene withp-alkoxybenzoyloxybenzaldehides. According to DSC and polythermic microscopy, all of the compounds exhibit an enantiotropic nematic mesophase in the 150–230 °C temperature range. A polycrystalline transition precedes the nematic transition. The liquid crystalline properties of the obtained compounds were investigated with respect to the number of carbon atoms in the terminal alkyl chain and the terminal hydroxyl group. The composition and structure of the obtained compounds were determined by elemental analysis and IR and NMR spectroscopy.

A series of new heteronuclear complexes of a ferrocene-containing Schiffs base (LH) with NiII, PdII, VIVO, and FeIII as the central atoms has been obtained. PdL2, VOL2 FeL2Cl, and [FeL2]2O complexes manifest liquid-crystalline properties and NiL2 is nonmesomorphic. The structures of the complexes synthesized have been established by magnetic measurements and IR and ESR spectroscopy. All of them except PdL2 are paramagnetic. The antiferromagnetic exchange interactions have been observed in the FeIII complexes. The correlation of liquid-crystalline properties with the geometry of the chelate centers is discussed.

A series of liquid crystal ferrocene-containing Schiff bases of general formula C5H5FeC5H4-C6H4-N=CN-(X)C6H3-O(O)-C6H4-OCnH2n+1 (X=H, OH, n=3–12) was obtained, together with several analogs, 1,1′-bis-substituted at the ferrocene fragment, having a thermotropic nematic mesophases. Derivatives with X=OH were used to obtain Cu2+ chelate complexes, of which the compounds with n=10 and n=12 displayed nematic liquid crystalline properties.

New liquid-crystalline heteropolynuclear complexes L2M (M=Cu2+ (2a), Pd2+ (2b)) were synthesized by the reactions of C5H5FeC5H4−C6H4NH−C2H2−(CO)−C6H4OC12H25 (1, LH) with copper(ii) and palladium(ii) acetates. Compound2b was found to possess monotropic nematic and smectic phases;2a exhibits the monotropic nematic phase and a phenomenon of “double melting”. The compositions and structures of compounds1 and2a,b were established by elemental analysis,1H and13C NMR, ESR, and IR spectroscopy.

Liquid crystalline complexes of the type [ML(LH)2](NO3)2, where LH=C7H15O-C6H3(OH)CH=N-C18H37 and M=Gd, Dy, and La, have been obtained. All of them exhibit the SA phase and have high magnetic birefringence constants due to the association of the complexes in solution. In the case of the dysprosium derivative, the effect is much stronger (four orders of magnitude greater than the usual value) because of the high magnetic anisotropy of the particles of the complex.

We describe the synthesis and liquid-crystalline properties of copper complexes with Schiffs bases. We show that when going from ligands to complexes, the mesophase interval narrows until it disappears and the phase transition temperature increases. In contrast to the case for ligands, no linear relationship is observed between the thermal stability of complexes and the electronic properties. The variation in the clearing point in the series of complexes with alkyl substituents is consistent with the even-odd contributions of the polarizability of the radicals to the total polarizability of the compounds.

In order to elucidate the influence of aryl or alkyl substituents on the nature of the ⋯ bond, which controls the complexing properties of the substances (Alk)n(Ar)3-nAsS (n = 0–3), the X-ray investigation of (p-MeC6H4)Et3AsS (TDEAS) and Ph2EtAsS (DPEAS) has been carried out. It was shown that the bond length AsS in these compounds has intermediate values (2.0896 and 2.0812 A) in respect to those previously found by us in Et3AsS and Ph3AsS (2.115 and 2.077 A). This confirms the conclusion that the increase of the number of aryl substituents in tertiary arsine sulfides leads to a decrease of electron density on the As atom along with simultaneous strengthening of the π-interaction between As and S.