Supramolecular systems of amphiphilic derivatives of calix[4]resorcinarenes and surfactants in chloroform

Abstract

Aggregation of amphiphilic calix[4]resorcinarenes (CRA) modified by carboxymethyl (1), 2 hydroxyethyl (2), methylamino acetal (3), and aminomethyl (4) fragments and their interac tion with some synthetic (5, 6) and natural (7, 8) surfactants in the low polarity solvent (chloroform) were studied by permittivity measurements and FT IR spectroscopy. Com pounds 1-4 and surfactants form aggregates at critical micelle concentrations (CMC) of 2.0, respectively. The CMC values of CRA-surfactant mixed aggregates depend on the surfactant structure and the structure and concentration of CRA. Analysis of the IR spectra of solutions of a series of amphiphilic CRA (2-4, 9, 10) and their mixtures with the cationic surfactant N cetyl N,N dimethyl N (2 hydroxyethyl)ammonium bromide (5) showed that an increase in the concentration of the solutions in individual and mixed systems is accompanied by a decrease in the molar integral intensities and intensities in the maxima of the absorption bands of the О-Н and С-Н bonds down to the CMC point, after which these values change slightly. The discovered effect, which is differently pronounced for all systems studied, indicates that both the polar "head" groups and nonpolar fragments of CRA and surfactant are involved in the formation of supramolecules of the reverse micelle type in all cases.Synthetically available calixarenes are the organized in a complicated manner three dimensional macrocyclic phenols that are able to form with ions and neutral mol ecules supramolecular aggregates modeling functions of complex biomolecules, for instance, transport 1 or cata lytic 2 functions. We have earlier 3,4 shown that amphiphilic aminomethylated calix[4]resorcinarenes (CRA) in aque ous and organic media are micelle forming surfac tants. These compounds can react with synthetic surfac tants, such as cetyltrimethylammonium bromide and Triton X 100, to form mixed supramolecular aggregates with high catalytic activity in hydrolysis of p nitrophenyl esters of phosphorus acids. 5-7 Interest in processes of self organization in solutions of surfactant mixtures 8 and compounds of complicated molecular architecture has recently increased considerably 1,9,10 primarily due to steady demands of modern nano and biotechnologies for new polyfunctional reagents. Therefore, studies of aggre gation of new amphiphilic derivatives of calix[4]resorcin arene and their interaction with synthetic and natural surfactants seems very urgent.The purpose of the present work is to study the aggre gation of a series of amphiphilic CRA modified by carboxymethyl (1), 2 hydroxyethyl (2), methylamino acetal (3), and aminomethyl (4) fragments in the absence and presence of synthetic surfactants (N cetyl N,N di methyl N (2 hydroxyethyl)ammonium bromide (5), Triton X 100 (6)) and natural membrane lipids (phospha tidylcholine (7), sodium deoxycholate (8)) in a medium of the low polarity solvent (chloroform). Permittivity measurements and FT IR spectroscopy served as methods of investigation. The influence of the structure and con cen...

Self-assembly of amphiphilic calixarenes and resorcinarenes in water

“…13). 41,42 In addition, mixed micellization of tris(hydroxymethyl)amide resorcinarene with a common cationic surfactant cetyl trimethylammonium bromide has been shown to increase the catalytic activity of the micelles of hydrolysis of phosphoric ester in water when compared to a pure resorcinarene amphiphile (Fig. 14).…”