Self‐Assembly of a Pyridine‐Based Amphiphile Complexed with Regioisomeric Dihydroxy Naphthalenes into Supramolecular Nanotubes with Different Inner Diameters

Abstract

dihydroxy naphthalene self-assembled in water to form nanotubes with inner diameters of 46, 38, 24, 18, and 11 nm in which the naphthalene molecules formed Jtype aggregates. In contrast, the amphiphile complexed with 1,2-, 1,3-, 1,4-, 1,7-, 1,8-, or 2,3-dihydroxy naphthalene formed nanofibers in which the naphthalene molecules formed Htype aggregates. The inner diameter of the nanotubes strongly depended on the regioisomeric dihydroxy naphthalene. UV-vis, fluorescence, infrared spectroscopy, Xray diffraction analysis, and differential scanning calorimetry showed that nanotubes with smaller inner diameters had weaker intermolecular hydrogen bonds between the tilted amphiphiles complexed with the naphthalene molecules within the membrane walls and showed larger Stokes shifts in the excimer fluorescence of the naphthalene moiety. These findings should be useful not only for fine-tuning the inner diameters of supramolecular nanotubes but also for controlling the aggregation states of functional aromatic molecules to generate nanostructures with useful optical and electronic properties in water.

Self-assembly of fullerene C60-based amphiphiles in solutions

“…Imae et al synthesized a cationic C 60 dendrimer where a poly(amidoamine) (PAMAM) dendron was coupled to an azide-functionalized C 60 monoadduct through click reaction. 80 The compound has four terminal amine groups which can be protonated (16). The formation of core-shell structures was confirmed by atomic force microscopy (AFM) and TEM observations (Fig.…”

“…Organic amphiphilic molecules, including both artificial and naturally occurring surfactants, are important building blocks to construct supramolecular structures in solutions such as micelles, vesicles, tubes, and lyotropic liquid crystals. [11][12][13][14][15][16][17][18] Each of these amphiphiles has one or several alkyl chains as the hydrophobic part. The hydrophobic/hydrophobic interaction and van der Waals attraction among these alkyl chains, together with the hydration forces and/or electrostatic interaction caused by the hydrophilic headgroups, drive the selfassembly and finally lead to the formation of various supramolecular structures.…”