Tailor-making of desired assemblies from well-designed monomers: use of calix[4]arene conformers as building blocks

Abstract

Water-soluble, conformationally-immobilized calix[4]arenes with cone and 1.3-alternate conformations (cone-I and 1.3-alternate-l , respectively) have been synthesized. In aqueous solution cone-I, with a cone-shaped surface, aggregated into micelles with 20-40 8, diameter whereas 1.3alternate-1, with a cylindrical surface, could not form such aggregates for concentrations up to 0.01 0 mol dm-3.

Evaluation of a cationic calix[4]arene: Solubilization and self-aggregation ability

“…9). These results differ from the DLS results previously reported (Arimori et al, 1993(Arimori et al, , 1995 where in aqueous 1.2% (w/v) aminocalix solution aggregates with a diameter of 2-4 nm were detected at 30 • C. However, the absence of experimental conditions in this report does not enable an investigation of these discrepancies. The large vesicles (aggregates) appear to be metastabile and slowly disintegrate to form more stable smaller vesicles.…”

“…7), which show abrupt inflections at concentration of aqueous aminocalix about 1% (w/v). Thus, our results do not disagree with the ones from Arimori et al (1993Arimori et al ( , 1995, but supplement them: the 0.001% (w/v) point corresponds to monomers → micelles transition, whilst the 1% (w/v) point corresponds to a micelles → vesicles or vesicles → vesicles' transition, i.e. the shift of equilibrium between two different vesicle types.…”

“…However, the critical micelle concentration for aminocalix in water at 17 and 30 • C was reported earlier (Arimori et al, 1993(Arimori et al, , 1995 to be significantly smaller with a value of 0.001% (w/v). Such large differences prompted us to investigate solutions over a range of aminocalix concentrations between 0.1 and 1.2% (w/v) more thoroughly using DLS and TEM as particle evaluation methods.…”

Encapsulation of Drug Molecules into Calix[n]arene Nanobaskets. Role of Aminocalix[n]arenes in Biopharmaceutical Field

“…In some cases, weak surface activity may be lost after conformational transition due to redistribution of hydrophilic and hydrophobic areas within the molecule. Compound 45 illustrates this concept as it aggregates into globular micelles in the cone conformation (Table ), whereas in the 1,3‐alternate form, it completely loses this ability …”

Selective Ion Transport and Complexation in Layer-by-Layer Assemblies ofp-Sulfonato- calix[n]arenes and Cationic Polyelectrolytes

“…In the course of our studies on self-assembled films for ionsieving and sieving of molecules, we became interested in calixarenes because of their basket-shaped structure, [33,34] which might enable selective transport due to complexation or sieving of distinct ions or molecules. Stimulated by the studies of Atwood et al, [35] Shinkai and co-workers, [36,37] and Raston and co-workers, [38,39] who demonstrated the formation of supramolecular assemblies containing p-sulfonato-calix[n]arenes and specific metal ions, we tried to prepare a number of multilayer films and membranes alternately built up from cationic polyelectrolytes and water-soluble calixarenes. Poly(vinyl amine) (PVA) and poly(allylamine hydrochloride) (PAH) were used as cationic polyelectrolytes, and tetra-p-sulfonato-calix [4]arene (calix4), hexa-p-sulfonato-calix [6]arene (calix6), and octa-psulfonato-calix [8]arene (calix8), as the water-soluble calixarenes.…”