[Show abstract][Hide abstract] ABSTRACT: The solubilization effect of 14-s-14 series dicationic surfactants is quantified via spectrophotometry using a thymolphthalein hydrophobic indicator. It is shown that the solubilization capacity of the studied micellar solutions with respect to the neutral form of thymolphthalein increases along with the length of the spacer moiety and grows by as much as five times upon transitioning from 14-2-14 to 14-6-14. It is concluded that the solubilization of thymolphthalein is accompanied by a shift in the acid-base equilibria in which this compound participates, as is reflected in the drop of its pK
a value and the shift of the region of color change.
No preview · Article · Feb 2016 · Russian Journal of Physical Chemistry
[Show abstract][Hide abstract] ABSTRACT: Poorly water-soluble calixresorcinarenes modified with amino acid (Ala, Val) at the upper rim was to form water-soluble mixed system with micelles of monocationic surfactants cetyltrimethylammonium bromide, cetyldimethyl(2-hydroxyethyl)ammonium bromide, and dicationic (gemini) surfactants, alkanediyl-α,ω-bis(dimethyltetradecylammonium bromides (14-s-14, where s= 2, 4, 6). By means of UV-Vis and DLS methods was demonstrated that the micellar systems surfactant/functionalized calixresorcinarene underwent structural changes within a relatively narrow concentration range followed by changes in solubilization capacity and polydispersity. Gemini surfactants and monocationic/gemini mixed surfactant systems were demonstrated to provide selectivity in their interaction with calixresorcinarene depending on the bulkiness of the substituent at the upper rim of calixresorcinarene, gemini surfactant spacer length, and mixed micelles. Obtained mixed systems represent a direction to create biocompatible water-soluble functionalized calixresorcinarene composition and may open perspectives in designing organized systems with controllable properties.
No preview · Article · Feb 2016 · Journal of Surfactants and Detergents
[Show abstract][Hide abstract] ABSTRACT: Supramolecular systems based on tetracationic pyrimidine-containing surfactants of acyclic and macrocyclic structures with varying nature of the spacer were studied. The critical micelle concentrations (CMC) and the hydrodynamic diameter of aggregates were determined, and the packing of molecules in the surface layer was analyzed. Insignificant differences in the CMC with variation in the nature of the spacer and in the transition from acyclic to macrocyclic surfactants suggest elimination of the structural factor in the self-organization of the investigated compounds. The molecular packing is shown to change greatly in the transition from monomeric pyrimidinophane to oligomeric tetracationic amphiphiles.
No preview · Article · Dec 2015 · Journal of Structural Chemistry
[Show abstract][Hide abstract] ABSTRACT: Gemini surfactants with hexadecyl tails and hydroxyethylated head groups bridged with tetramethylene (G4), hexamethylene (G6) and dodecamethylene (G12) spacers were shown to self-assemble at the lower critical micelle concentration compared to their conventional m-s-m analogs. The lipoplex formation and the plasmid DNA transfer into different kinds of host cells were studied. In the case of eukaryotic cells, high transfection efficacy has been demonstrated for DNA–gemini complexes, which increased as follows: G6 < G4 < G12. Different activity series, i.e., G6 > G4 > G12 has been obtained in the case of transformation of bacterial cells with plasmid DNA–gemini complexes, mediated by electroporation technique. Solely G6 shows transformation efficacy exceeding the control result (uncomplexed DNA), while the inhibitory effect occurs for G4 and G12. Analysis of physico-chemical features of single surfactants and lipoplexes shows that compaction and condensation effects change as follows: G6 < G4 ≤ G12, i.e., agree with the order of transfection efficacy, which is supported by membrane tropic properties of G12. On the other hand, gel retardation assay and docking study testify low electrostatic affinity in G12/DNA pair, thereby indicating that hydrophobic effect probably plays important role in the lipoplex formation. Two factors are assumed to be responsible for the inhibition effect of gemini in the case of transformation of bacterial cells. They are (i) an unfavorable influence of cationic surfactants on the electroporation procedure due to depressing the electrophoretic effect; and (ii) antibacterial activity of cationic surfactants that may cause the disruption of integrity of cell membranes.
Full-text · Article · Dec 2015 · Colloids and surfaces B: Biointerfaces
[Show abstract][Hide abstract] ABSTRACT: The aggregation properties of supramolecular systems based on polyethyleneimines and cationic surfactants with a bicyclic head group — mono- and diquaternized derivatives of 1,4-diazabicyclo[2.2.2]octane are studied by surface tension measurements, potentiometry, conductivity measurement, and dynamic light scattering. The critical aggregation concentrations of individual and mixed systems based on them, as well as the size of the ensembles they form are determined. The relationship between the aggregation behavior and hydrophobicity of the polymer and the structure of the cationic surfactant is established.
No preview · Article · Dec 2015 · Journal of Structural Chemistry
[Show abstract][Hide abstract] ABSTRACT: The internal structure of DNA lipoplexes with hydroxyethylated alkylammonium gemini surfactants (GS) with high transfection activity was studied by circular dichroism. It was shown that the efficiency of transfection of HEK293T cells with the pEGFP-N1 circular plasmid was different from zero only in the region of existence of chiral supramolecular DNA-GS complexes and reaches a maximum at concentrations at which the spontaneous aggregation of components is observed.
Full-text · Article · Nov 2015 · Doklady Biochemistry and Biophysics
[Show abstract][Hide abstract] ABSTRACT: The aggregation behavior and flow characteristics of systems based on zwitterionic surfactant, erucyl amidopropyl betaine, silica and alumina nanoparticles in a wide range of surfactant concentrations from molecular to micellar solutions were studied using surface tensiometry, conductometry, dynamic and electrophoretic light scattering, and rheology techniques. The adsorption of zwitterionic surfactant molecules occurs on both positively and negatively charged surfaces via an electrostatic interaction mechanism. As a result, addition of a small amount silica nanoparticles (0.5–0.8 wt%) increases the surfactant solution's viscosity by more than two times.
No preview · Article · Oct 2015 · Journal of Surfactants and Detergents
[Show abstract][Hide abstract] ABSTRACT: Sequential substitution/ring cleavage/addition reaction of 1-(cyclohex-1-enyl)-piperidine and -pyrrolidine with chloropyruvates has been accomplished for the synthesis of various polysubstituted 4,5,6,7-tetrahydroindoles. This one-pot, general and highly regioselective method avoids harsh conditions and expensive catalysts. It proceeds with high atom-efficiency and shows a broad substrate scope and functional group tolerance, making it a highly practical approach for the preparation of various tetrahydroindole derivatives. A family of 17 tetrahydroindoles was synthesized in good yields, which is indicative of the general character of this reaction. 10 of the tetrahydroindole derivatives with various substituents were successfully transformed into the corresponding indoles. This methodology allows access to indoles bearing ω-halo- (mostly chloro-)butyl and pentyl substituents at the nitrogen atom (by variation of enamines) and at the C2, C3 positions (by variation of pyruvates, including bromoaryl and chloroalkyl derivatives). The reaction can be used in conjunction with enamine synthesis offering a practical three-component heteroannulation methodology to produce 4,5,6,7-tetrahydroindoles from cyclohexanone, pyrrolidine and arylchloropyruvates.
[Show abstract][Hide abstract] ABSTRACT: The biomimetic nature of micellar catalysis can significantly affect the rate of chemical reactions due to the effects of concentration and the change of microenvironment. Here, a key role is played by the nature of the head group. The catalytic activity of alkyltriphenylphosphonium bromides (TPPB-n; n= 10, 12, 14, 16, 18; n is the number of carbon atoms in alkyl groups) in the nucleophilic substitution of p-nitrophenyl esters of alkylchloromethylphosphonic acid were investigated by the method of spectrophotometry. Using pyrene, prodan and Sudan I as probes the values of critical micelle concentrations and aggregation numbers were determined. A comparison of the results of kinetic dependence processing by Berezin equation obtained for TPPB series with the known ammonium analogues was carried out. It was found that for TPPB- n series, the higher acceleration of reaction has been achieved due to concentration factor compared to ammonium surfactants. This agrees with the fact that alkyltriphenylphosphonium bromides demonstrate higher aggregation activity forming micelles with higher solubilizing capacity.
No preview · Article · Oct 2015 · Colloids and Surfaces A Physicochemical and Engineering Aspects
[Show abstract][Hide abstract] ABSTRACT: In this review, we summarized and analyzed the literature data (from 1963 to March, 2014) on the synthesis and properties of quaternary ammonium derivatives of citronellal, menthol, camphor, lambertian acid, dehydroabietic acid, levopimaric acid, isosteviol, steviol, betulinic acid, dihydrobetulinic acid, platanic acid, oleanolic acid, ursolic acid, and polyprenols. Functionalization of terpenoids with ammnoium groups offers them new properties, such as cholinotropic, antiviral, and antimicrobial activities, or transforms them into chiral ionic liquids having a practical potential for application as chiral phasetransfer catalysts. The synthesis of ammonium derivatives of terpenoids possessing properties of cationic lipids or dimeric bis-quaternary ammonium surfactants was proved to have a promising outlook. A specific attention was paid to the method developed for transformation of any hydrophobic terpenoid or steroid into an amphiphilic water-soluble compound self-organized in the aqueous medium into vesicles (liposomes) forming cell-penetrating complexes with DNA.
No preview · Article · Sep 2015 · Russian Chemical Bulletin
[Show abstract][Hide abstract] ABSTRACT: The critical micelle concentration, surface potential, and degree of binding of counterions in aqueous micellar solutions of N-cetyl-N-methylmorpholinium bromide and its analog containing the hydroxyethyl moiety in the head group were determined using a complex of physicochemical methods. The aggregation behavior of these compounds was found to vary insignificantly, whereas the catalytic effect of the hydroxyethyl derivative on the hydrolysis of carboxylic acid esters more than an order of magnitude exceeds the effect of the non-functionalized surfactant. One of the reasons for this phenomenon can be an increase in the micropolarity in the chemical reaction zone detected by fluorescence spectroscopy.
No preview · Article · Aug 2015 · Russian Chemical Bulletin
[Show abstract][Hide abstract] ABSTRACT: This study depicts the construction of a water-soluble form of glycine C-methylcalixresorcinarene (CR) by using different approaches of supramolecular and colloid chemistry. The first approach involves the ionization of hydroxyl groups of CR under the alkaline condition. The second is a supramolecular approach, which takes advantage of the high water solubility of N-methylglucamine. The third approach consists of the solubilization in surfactant solutions.
No preview · Article · Aug 2015 · Journal of Molecular Liquids
[Show abstract][Hide abstract] ABSTRACT: Complexation of decanucleotide (GCGTTAACGC) with mono- and dicationic surfactants (hydrodynamic diameter of lipoplexes ≤200 nm) is accompanied by the compensatory change of electrokinetic potential from −54 to +50 mV. The complexation efficiency considerably increases with introduction of a hydroxyethyl fragment into the surfactant head group.
No preview · Article · Jul 2015 · Russian Chemical Bulletin
[Show abstract][Hide abstract] ABSTRACT: The aim of this work is the development of stable fluorophore-quencher pairs with a controlled response for bioassay in the laboratory. The widely used in bioanalysis pyrene and its water-soluble derivative were selected as organic fluorophores. Water-soluble aminomethylated calixarene with sulfonatoethyl groups at the “lower rim” was chosen as a stabilizer. We have established a strong fluorescence quenching in the solution of resorcinarene even at low premicellar concentrations which indicates the pyrene transition into a non-polar microenvironment. The data on the influence of pH, buffer composition, and the macrocyclic platform on the fluorescence quenching of pyrene in the presence of resorcinarene were obtained. The temperature dependence of the fluorescence quenching of pyrene was obtained with the aim of establishing the mechanism of the formation of complex fluorophore-resorcinarene (static versus dynamic quenching).
No preview · Article · Jun 2015 · Journal of Molecular Liquids
[Show abstract][Hide abstract] ABSTRACT: C-methylcalixresorcinarenes with glycine, d,l-alanine and d,l-valine residues and their water-soluble forms are obtained. The water solubility enhancements of these macrocycles depend on the structures of the amino acid residues; the solubility of macrocycles in aqueous solutions is enhanced by increasing basicity with branching amino acid residues. The controlled fabrication of specific nanostructures from the self-assembly of molecular building blocks through fine pH tuning by the use of sodium hydroxide and sodium n-dodecyl sulfate renders the calixresorcinarenes studied more soluble in water.
No preview · Article · May 2015 · Tetrahedron Letters
[Show abstract][Hide abstract] ABSTRACT: The synthesized cationic surfactant bearing a glucamine fragment forms spherical micelles at about 0.7 mmol dm-3 and displays specific aggregation characterized by a sharp growth of micelles and a change in their properties within a narrow concentration range about 10 mmol dm-3.
No preview · Article · May 2015 · Mendeleev Communications
[Show abstract][Hide abstract] ABSTRACT: Nanocapsules (≤200 nm) with a protection effect toward small hydrophobic guests (p-nitrophenyl laurate and acetylsalicylic acid, aspirin) and a tunable sustained release behavior have been fabricated through the layer-by-layer deposition of polyacrylic acid and modified chitosan. Cationic surfactant, cetyltrimethylammonium bromide, was used to increase the affinity of polyelectrolyte to the substrate. The release profile was monitored through original protocol involving a fast cleavage of the substrate released and a spectrophotometric control of the product. The shell permeability of the capsules and hence their protective effect may be tuned through the variation of the number of layers deposited, the sonication, and the adjustment of solution pH. Importantly, the dispersed loads serving as a template for the capsule fabrication may control their properties, including shell permeability.
No preview · Article · Apr 2015 · Colloids and Surfaces A Physicochemical and Engineering Aspects
[Show abstract][Hide abstract] ABSTRACT: The work includes the determination of relationships of the solubilization process of biodegradable hyperbranched polyester polyols Boltorn Hx of second, third and fourth generation by nonionic surfactants (TX-100, Brij-35, Tween-20). The impact of hyperbranched polyester polyols in binary systems Boltorn Hx/surfactant on surface-active properties of surfactants, dimensions of assemblies and solubilization capacity has been estimated with respect to Orange OT dye. It has been shown that solubilization capacity rises by an order of magnitude in binary system Boltorn Hx/TX-100 and decreases in binary system Boltorn Hx/Tween-20.
Full-text · Article · Mar 2015 · Colloids and Surfaces A Physicochemical and Engineering Aspects