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[Display omitted] • Calix[4]arenes with 1,2,3-triazole and 1,3-diketone groups as ligands of Eu3+ (La)3+. • Diversity in complex stoichiometry from UV–Vis and NMR data in solutions. • NMR data under slowed down ligand exchange regime specify binding sites of Eu3+ (La)3+. • DFT data reveal complex structures in correlation with their thermodynamic parameters. • Optimal complex structure for greatest Eu3+- luminescence is demonstrated. The present work introduces two calix[4]arenes (cone and 1,3-alternate isomers) bearing pairs of 1,2,3-triazole and 1,3-diketone groups as binding sites of Eu3+ (La3+) ions. Combination of UV–Vis, 1H NMR spectroscopy and DFT calculations allowed to evaluate the structure of the lanthanide complexes and specify the groups participating in the coordination. It was found that cone calix[4]arene forms the 2:1 (ligand: Ln3+) complex arisen from the coordination of Ln3+ ions via both 1,2,3-triazole and 1,3-diketonate groups as well as the 2:2 complex form, where Ln3+ ions are coordinated via 1,3-diketonate groups only. The quantum chemical calculations reveal that the 2:2 complex is more thermodynamically favorable than the 2:1 one, which correlates with the NMR data. It is worth considering the coordination of Ln3+ ions with both triazole and 1,3-diketonate groups as the reason for the specific slowed down ligand exchange for 2:1 and 2:2 complex forms. The comparative analysis of the Eu3+-centered luminescence reveals the cone calix[4]arene as more efficient antenna for Eu3+ ions than the 1,3-alternate calix[4]arene, where 1,2,3-triazole and 1,3-diketone substituents are localized at the opposite sides of the macrocycle. The growing degree of accumulation of the 2:1 complex is followed by an increase in Eu3+-centered luminescence for both calix[4]arene ligands. [ABSTRACT FROM AUTHOR]

Here we present the supramolecular surfactant-macrocycle system which properties are independent on system composition in the wide range of components concentrations. The study of the interaction of octacarboxy-tetra( p -phenylene-oxy-pentyl)calixresorcinarene ( C5R ) and cetylpyridinuim chloride (CPC) in mixed aqueous solutions were performed by dynamic light scattering and electrophoretic methods, 1 H and FT-PGSE NMR methods, absorption and fluorescence spectroscopy, and TEM. The variation of CPC/ C5R molar ratio from 30/1 to 10/1 leads to the formation of nanoassociates with similar composition, size, surface potential value, and improved (in compare with CPC) solubilizing properties. The preparation of mixed supramolecular systems which properties are independent on system composition in the wide range of components concentrations is an elegant example of the producing of colloidal materials with the required morphology and properties. [ABSTRACT FROM AUTHOR]

The reactions ofdialkyl[(3,5-di-tert-butyl-4-oxo-2,5-cyclohexadienyl)methyl]phosphonates with N-nucleophiles (aminoacetaldehyde dimethyl acetal and diethyl [(2,2-dimethoxyethyl)aminomethyl]phosphonate give new aminophosphonates containing the 3,5-di-tert-butyl-4-hydroxyphenyl substituent, in addition to the acetal group. The crystal structure of diethyl {(3,5-di-tert-butyl-4-hydroxyphenyl)[(2,2-dimethoxyethyl)amino]methyl}phosphonate is elucidated. The presence of a chiral carbon atom and prochiral phosphorus atom in the aminophosphonate products is responsible for the complicated pattern in the1H NMR spectra, the features of which are discussed. [ABSTRACT FROM PUBLISHER]

Abstract: Herein two sensitive techniques, i.e., NMR self-diffusion measurements and dielcometry are involved to test the association of cationic surfactant 4-aza-1-tetradecyl-1-azoniabicyclo[2.2.2]octane bromide (BC-14) and polyethyleneimine hydrophobized with tetradecyl moieties (PEI-14) in their chloroform solutions. The data obtained make it possible to nominate these methods as highly powerful instruments for the identification of a very uncooperative aggregation. Mixed BC-14/PEI-14 association is probably observed only at a relatively high polymer concentration, which is indicated by a decrease in the diffusivity of surfactant molecules. Aggregation is strongly promoted by the addition of water, with a high [water]/[BC-14] molar ratio of 60 attained. Even a very slight association has a serious impact on the reactivity, the pre-concentration effect and the shift of acid–base equilibrium of solutes. A 4-fold acceleration of the reactivity of an organophosphorus pollutant occurs in the BC-14 reverse micelles due to the concentration of reagents and changes in their microenvironment, which strongly supports the very idea of association. The high binding constants derived from the analysis of kinetic data provide evidence on high degree of concentration of compounds, while changes in the microenvironment affect their ionization. These impacts may be of key importance in analytical procedures and the chemical reactivity of compounds in nonpolar media. [Copyright &y& Elsevier]

The condensation of thiophosphorylated aldehydes 1 and 2 with resorcinol and its derivatives leads to the formation of the new type of calix[4]resorcinols with four thiophosphoryl groups inserted to the substituents located in methylidene bridges of the molecule. The conformation of these compounds was found to be 'flattened partial cone' or 'chair,' which was determined by NMR methods and a single-crystal X-ray diffraction study. GRAPHICAL ABSTRACT [image omitted] [ABSTRACT FROM AUTHOR]

New calix[4]resorcinols containing four organochlorine moieties have been synthesized in high yields via one-step condensation of resorcinol, 2-methylresorcinol or pyrogallol with 4′-formylphenyl 4-(chloromethyl)benzoate. It has been found that the diastereomeric ratio of the products depends substantially on the starting polyphenol. The rctt - and/or rccc -diastereomers have been isolated and their structure and composition have been determined by 1H, 13C NMR and IR spectroscopy, MALDI mass spectrometry and elemental analysis, the crystal structure of one rctt -product has been established by single crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Amphiphilic zwitter-ionic calix[4]resorcinarenes form self-associates in an aqueous solution. • Calixresorcinarenes bearing undecyl and dodecyloxyphenyl chains are non-surface active. • Sulfobetaine and hydroxysulfobetaine calixresorcinarenes bearing pentyl chains are surface active. Here the amphiphilic calix[4]resorcinarenes, which form self-associates in an aqueous solution but do not exhibit surface activity, are described. Aqueous solutions of calix[4]resorcinarenes with different zwitter-ionic groups on the upper rim: carboxybetaine (C 5 -CB, C 11 -CB, C 12 OPh-CB), sulfobetaine (C 5 -SB, C 11 -SB), hydroxysulfobetaine (C 5 -hSB, C 11 -hSB), - and different hydrophobic substituents on the lower rim (pentyl, undecyl, dodecyloxyphenyl) were studied by fluorimetry, Fourier transform pulsed-gradient spin-echo (FT-PGSE) NMR spectroscopy, UV–vis spectroscopy, dynamic light scattering (DLS), and tensiometry. It was found that all macrocycles spontaneously form self-associates in an aqueous solution, but only sulfobetaine and hydroxysulfobetaine calixresorcinarenes with pentyl substituents on the lower rim are surface active. The critical association concentration (CAC) values, which were obtained by different methods, as well as values of averaged hydrodynamic diameter, averaged self-association numbers, solubilizing power, and other parameters of self-association are presented and discussed. [ABSTRACT FROM AUTHOR]

Novel calix[4]resorcinols containing four triazole fragments on the aromatic substituents of the calixarene framework were synthesized via a one-step condensation of resorcinol and its derivatives with 4-(1-benzyl-1 H -[1,2,3]triazol-4-ylmethoxy)benzaldehyde. The macrocyclic products are rctt - and/or rccc -isomers, which were isolated and characterized by NMR and single crystal X-ray diffraction studies. The same products were also prepared via the click -reaction of benzyl azide with previously synthesized calix[4]resorcinols containing four alkyne terminal groups on the aromatic substituents. In this case, only rctt -diastereomers of the corresponding calixarenes were isolated, which is governed by conformational features of the starting macrocycles. [ABSTRACT FROM AUTHOR]

The catalytic activity of two homological series of cationicsurfactantsbearing a hydroxyalkyl fragment in the head groups R(CH3)2N+(CH2CH2OH)Br–and R(CH3)2N+(CH2CH2CH2OH)Br–towardthe cleavage of the p-nitrophenyl esters of carbonicacids of different hydrophobicity (acetate, caprilate, caprinate,laurate, myristate) is shown to exceed that of typical cationic surfactantswith the trimethylammonium (TMA) headgroup. The catalytic effect increaseswith the alkyl chain length of surfactants and nonmonotonous changesin the series: acetate < caprilate < myristate < laurate< caprinate, reaching 750 times. NMR and IR spectroscopy studiesand the surface potential calculations revealed that the higher catalyticeffect of hydroxyalkylated surfactants is not due to their highersurface potential and binding capacity toward substrates. This isin line with finding that binding constants for TMA series are higherthan for their hydroxyalkylated analogues, which was demonstratedby the fitting of kinetic datain terms of the pseudophase model. The microenvironment factor ratherthan concentrating effect is responsible for the advanced catalyticproperties of hydroxyalkylated surfactants in the micellar phase. [ABSTRACT FROM AUTHOR]

Abstract: The structural peculiarities of tetrathiacalix[4]arenes with acetylhydrazide substitutes in cone and 1,3-alternate conformations have been determined by means of X-ray analysis, IR and NMR spectroscopy. The structural and molecular modeling data were used in the interpretation of binding properties of calix[4]arene tetrahydrazides. The quantum-chemical calculations at the DFT level using the PBE exchange–correlation functional were performed for the complexation of 1,3-alternate conformer of tetrathiacalix[4]arene with Ag+ ion. It was shown that the removal of tert-butyl groups from tert-butyltetrathiacalix[4]arene platform facilitates a bis-ligand coordination of the metal ion and leads to a remarkable increase of Ag+ extraction efficiency. [Copyright &y& Elsevier]

• Two new calixresorcinarene-mPEG conjugates bearing acylhydrazone bonds are presented. • The conjugates demonstrate pH-responsivity and have low hemo- and cytotoxicity. • The cytotoxicity of conjugate-encapsulated Dox against tumor cells is increased. • The photodynamic action of conjugate-encapsulated MB against tumor cells is increased. The synthesis of new conjugates of calix[4]resorcinarenes and methoxy-PEG via acylhydrazone bonds and their study in the formation of pH-sensitive low-toxic supramolecular drug delivery systems have described. The syntheses have been performed on the base of two calix[4]resorcinarenes in chair and boat conformations to obtain the dendrimer-like and amphiphilic conjugates, respectively. The structures of the conjugates have been confirmed by 1H, 13C NMR, and FT-IR spectroscopy, Maldi-TOF mass spectroscopy, and SLS method. The self-association of both amphiphilic and dendrimer-like conjugates has been found (NMR FT-PGSE, fluorimetry, DLS and TEM methods). The hydrolysis of the conjugates at pH 5.5 (proved by 1H NMR and FT-IR spectroscopy, DLS method) lead to the improved release of the conjugate-encapsulated Dox. The low hemolytic activity and low cytotoxicity against Chang liver cells of the conjugates and products of their hydrolysis have been demonstrated. Meanwhile, the improved cytotoxicity and photodynamic activity of conjugates-encapsulated drugs (Dox and Methylene Blue, respectively) has been found in vitro. The results have indicated the potential using of the calix[4]resorcinarene-mPEG conjugates bearing acylhydrazone bonds as supramolecular drug delivery systems. [ABSTRACT FROM AUTHOR]

This is the first report on the synthesis and characterization of tetra-1,3-diketone derivatives of tetrthia- and calix[4]arenes substituted by acetylacetonyl or dipivaloylmethanyl moieties at the upper rim and bearing hydroxyl groups at the lower rim as ligands for Tb 3+ complexes. The spatial structure and tautomeric content for the synthesized ligands have been determined by means of X-ray, IR and NMR spectroscopy. Comparison of the sensitizing properties of tetrathiacalix[4]arenes and their calix[4]arene analogues on the Tb 3+ -centered luminescence in DMF solutions has been performed. A substantial enhancement of the luminescent properties of Tb 3+ - complexes with tetra-1,3-diketone ligands promoted by the tetrathiacalix[4]arene scaffold was established. [ABSTRACT FROM AUTHOR]

Abstract: Here we report the clouding phenomenon, conductivity, 1H NMR spectroscopy and dynamic light scattering data of mixed sodium dodecylsulfate–calix[4]resorcinarene micellar solutions in combination with tetrabutyl-, tetraethyl-, tetramethylammonium bromides and choline chloride. The NMR data reveal tight (the binding constant is about 104) guest–host binding of calix[4]resorcinarene in alkaline conditions with tetraethyl-, tetramethylammonium and choline cations. This binding occurs at rather small concentrations of the external quaternary salts (0–0.0005 M) and leads to dramatic increase of the cloud point temperature. The obtained data are discussed in the correlation with the micellar size changes, caused by the ion exchange due to the variation of quaternary salt concentrations. [Copyright &y& Elsevier]