Novel self-assembling system based on resorcinarene and cationic surfactant

Mixed association of calix[4]resorcinarene with ethyl sulfonate groups on the lower rim and dimethylaminomethyl groups on the upper rim (CR) and cationic surfactant 4-aza-1-hexadecyl-azoniabicyclo[2.2.2]octane bromide (DABCO-16) is studied by methods of tensiometry, conductometry, potentiometry and NMR spectroscopy at fixed CR concentration and varied surfactant concentration. Beyond ca. 0.4 mM of DABCO-16, mixed aggregates enriched by CR are proved to be formed due to electrostatic forces, while beyond ca. 5 mM, aggregates enriched by surfactant occur due to the hydrophobic effect. Spectrophotometry monitoring of the solubilization of a hydrophobic dye, Orange OT, demonstrated that only the second type of mixed aggregate enriched by DABCO-16 is capable of binding the organic probe, while the mixed system where the surfactant is a minor component shows no binding capacity towards Orange OT. This finding can be used for the design of nanocontainers with controllable binding/release properties.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich

Die Entwicklung eines lichtgesteuerten Molekularschalters - ein Nanobauteil für den Einsatz in funktionellen Schaltkreisen und Nanomaschinen

Our target is the engineering of a light-gate molecular switch for the artificial ion channel, which will enable artificial ion channels to operate successfully in microfluidic systems, biomimetic sensors and various technical devices. A stable but reversible switch mechanism design is crucial, because the artificial ion channels known to date are lacking any control mechanism. Our artificial molecular switch is divided in two parts: the body part (calixarene) and a gate part based on light-responsive azo groups. The key to the controlling mechanism is the conformational change between cis and trans isomers, which is translated into movement of the gate. The gate is very robust and can either block or let the ions pass the molecular switch. Patch clamp investigations indicate successful integrations of gated artificial ion channels into lipid membranes.Unser Ziel ist die Entwicklung eines lichtinduzierten Molekularschalters für künstliche Ionenkanäle, der als Nanobauteil für die Entwicklung von Sensoren in mikrofluiden Systemen, in biomimetischen Sensoren und in verschiedenen technischen Baugruppen eingesetzt werden soll. Für ein stabiles und zugleich reversibles System ist der Schaltmechanismus entscheidend, da die künstlichen Ionenkanäle bisher – soweit bekannt – keinen Regelmechanismus besitzen. Unser künstlicher molekularer Schalter setzt sich aus einem Rumpfteil (Calix[4]resorcinaren) und einer Schalteinheit, basierend auf lichtempfindlichen Azogruppen, zusammen. Die Schalteinheit ist sehr widerstandsfähig, kann den Ionenfluss blockieren oder die Ionen durch den Ionenkanal passieren lassen. Durch Bestrahlung wird die Kanalaktivität unterdrückt und reversibel wiederbelebt. Mittels Patch-Clamp-Untersuchungen wird das Schalten der synthetischen Ionenkanäle überprüft

Metal ion retention from aqueous solution using the ultrafiltration technique: Preparation, retention capacity of copolymers of N-maleimide derivatives with β-methylhydrogen itaconate and metal complexes

Chlorophenylmaleimide (CI-PhMI) and N-maleoylglycine (N-MG) with β-methylhydrogen itaconate (β-MHI) were copolymerized by radical polymerization, and their metal ion retention capacity (MRC) and thermal behavior were studied. The copolymers were obtained by varying the mole fraction of CI-PhMI or N-MG in the feed from 0.25 to 0.75. The monomer reactivity ratios, r1 and r2, were determined using the Kelen-Tüdös method. The molecular weight and polydispersity were also determined. The capacity to remove several metal ions, such as Cu(II), Cr(III), Co(II), Zn(II), Ni(II), Pb(II), and Fe(III), in aqueous phase was determined using the liquid-phase polymer-based retention technique. Inorganic ion interactions with the hydrophilic polymer were determined as a function of pH and the filtration factor. The MRC depends strongly on the pH. Metal ion retention increased with increases in pH and the content of β-MHI units in the macromolecular backbone. The copolymers and polymer-metal complexes

Amphiphilic O-functionalized calix[4]resocinarenes with tunable structural behavior

Novel amphiphilic calix[4]resorcinarenes oxyethylated at the upper rim and alkylated at the lower rim (CR-CnH2n+1, here n is the number of carbon atoms in the alkyl substituent; n = 2,5,7,8,9,11) were synthesized, and their association behavior in water-organic solvents was explored. Surface properties and the association behavior of CRs were shown to be strongly controlled by their structure and the nature of the co-solvent. Solely CR-C5H11 demonstrates surface activity in the mixed water-DMF and water-DMSO solutions, while no surface activity occurs in the water-THF mixture. The DLS measurements revealed a very low concentration threshold of the aggregation (around 0.01 mM) for the CR series including surface inactive compounds. In water-DMF and water-DMSO solutions the CRs of low hydrophobicity were shown to associate through an open model with the formation of large aggregates of 300-400 nm, while more hydrophobic CRs can associate through a closed model and form rather small micelle-like aggregates of 10 to 20 nm. © 2014 The Royal Society of Chemistry.19101sciescopu

A Supramolecular Amphiphile Based on Calix[4]resorcinarene and Cationic Surfactant for Controlled Self-Assembly

A novel supramolecular system based on calix[4]­resorcinarene sulfonatoalkylated at the lower rim and piperidine-methylated at the upper rim and the cationic surfactant hexadecyl-1-azonia-4-azobicyclo[2.2.2]­octane bromide was investigated by methods of NMR, tensiometry, conductometry, potentiometry, dynamic light scattering, X-ray powder diffraction, and spectral probe techniques. Both types of molecules were found to self-associate in aqueous solution, with aggregates of different morphology formed. Importantly, a supramolecular amphiphilic binary system with controlled structure and binding behavior could be fabricated. At high surfactant concentration, the formation of its own aggregates takes place. In the systems with the excess of cyclophane the supramolecular amphiphiles are formed, which, in turn, self-assemble in particles with a large hydrophobic core. Thereby the structure of supramolecular species is determined by relative fractions of components and, hence, could be selectively controlled. The found properties can be used for the design of nanocontainers with the controlled cavity size