Supramolecular barrels from amphiphilic rigid–flexible macrocycles

Abstract

Precise control of supramolecular objects requires the rational design of molecular components, because the information determining their specific assembly should be encoded in their molecular architecture. In this context, diverse self-assembling molecules including liquid crystals, dendrimers, block copolymers, hydrogen-bonded complexes and rigid macrocycles are being created as a means of manipulating supramolecular structure. Incorporation of a stiff rod-like building block into an amphiphilic molecular architecture leads to another class of self-assembling molecules. Aggregation of rod building blocks can generate various nanoscale objects including bundles, ribbons, tubules and vesicles, depending on the molecular structure and/or the presence of a selective solvent. We present here an unusual example of supramolecular barrels in the solid and in aqueous solution, based on the self-assembly of amphiphilic rigid-flexible macrocycles driven by non-covalent interactions. Preliminary experiments show that these amphiphilic macrocycles are membrane-active. The amphiphilic macrocycles might thus lead to an excellent model system for exploring biological processes in supramolecular materials.

Synthetic Multifunctional Nanoarchitecture in Lipid Bilayers: Ion Channels, Sensors, and Photosystems

“…For example, from the structural point of view, O-NDIs are just one out of many possible rigid-rod molecules beyond p-oligophenyls that promise access to new structures with new functions. [15][16][17][18][19][20][21][22][23][24][25] The imaginable variability of hoops beyond -sheets in barrel-stave supramolecules simply enormous. Access to transmembrane rigid-rod -stack architecture is naturally not limited to NDI -stacks.…”

“…11,12 Somehow the antithesis to foldamers, 13,14 these simple sturdy rods have attracted considerable scientific attention for applications in the materials sciences. [15][16][17][18][19][20][21][22][23][24][25] Highlights beyond the minimalist oligoacetylenes 17 1 and p-oligophenyls 18,19 2 include the oligonaphthalenes 3 studied in the Tsubaki group because of their exceptional stereochemical complexity ( Fig. 1).…”

The determination of the ion selectivity of synthetic ion channels and pores in vesicles

“…For an organic chemist entering the field without BLMs, [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] LUVs provide a user friendly and, according to the comparative studies discussed below, valid alternative. Among several possible methods to determine anion/cation selectivity of synthetic ion channels in vesicles, the HPTS assay worked best in our hands (Fig.…”

Facial amphiphiles in molecular recognition: From unusual aggregates to solvophobically driven foldamers

“…When this facial amphiphile aggregates, the hydrophobic contact is confined by the looped hydrophilic side chains. Macrocycles with high proportions of PEG chains assembled into donut-like nanoclusters [29] and those with slightly lower PEG portions formed long tubes [30]. Very recently, macrocycle 15, consisting of a rigid hydrophobic core and three flexible tri(ethylene glycol) side chains (Tg), was reported to form stable vesicles through the face-to-face stacking of the aromatic cores [31].…”