Cooperative Assembly of Discrete Stacked Aggregates Driven by Supramolecular Host–Guest Complexation

Abstract

p-Sulfonatocalix[4]arene (SC4) interacts with the aromatic dye crystal violet (CV) to form complexes with stoichiometries ranging from SC4:CV = 1:1 up to 1:5 both in solution and in the gas phase. While the 1:1 complex is of the inclusion type, as frequently observed for other guests, in the higher-order complexes the CV molecules interact with SC4 in a peripheral manner. The formation of such complexes is driven by ionic interactions established between the dye and the calixarene and by CV-CV stacking interactions. The application of an advanced fitting procedure made possible a quantitative analysis of the UV-vis data and allowed the determination of the stepwise binding constants. This unprecedented approach provides evidence that the formation of the highest-order complexes occurs through a cooperative mechanism. Moreover, the development of a quantitative analytical model enables the possibility of using this type of system for water-soluble sensing assays, as is also exemplified in the present work.

Stimulus-Responsive Supramolecular Host–Guest Assembly of a Cationic Pyrene Derivative with Sulfated β-Cyclodextrin

“…p -Sulfonatocalixarene represents a host molecule in which the sulfonato group is substituted in place of the hydroxyl groups at the upper rim of the calixarene, and has recently received tremendous attention from the supramolecular aggregation point-of-view . There are several reports in the literature which show that p -sulfonatocalixarene complexes with various guest molecules like cationic aromatic amphiphilic molecules and increases the probability of self-aggregation of guest molecules by increasing the stability of aggregate or by controlling the degree of aggregation. − These self-assembled aggregates of the guest molecules, promoted by p -sulfonatocalixarenes, have found tremendous application in a variety of areas, such as in constructing fluorescence sensing systems to monitor enzymatic reactions, − drug delivery by supramolecular binary vesicles, − clinical treatment of viologen poisoning, and in pesticide detoxification. , …”

Effect of Macrocycle Size on the Self-Assembly of Methylimidazolium Surfactant with Sulfonatocalix[n]arenes

“…12 The binding to SCXn facilitates the aggregation of aromatic or amphiphilic molecules. [13][14][15][16][17] The interaction of the macrocycle homologue comprised of four sulfonatophenol units (SCX4) with a natural cationic protein, protamine resulted in supramolecular vesicle which disintegrated in a controlled manner upon addition of trypsine. 18 Enzyme-induced cleavage 4 supramolecular micelles barely altered upon increase of surfactant concentration up to the critical micelle concentration (cmc) of the free C 12 TAB.…”

Reversible Nanoparticle–Micelle Transformation of Ionic Liquid–Sulfonatocalix[6]arene Aggregates

“…In contrast to cyclodextrins or cucurbiturils, which induces the dissociation of aggregates by host-guest complexation, 21 the binding to SCXn promotes the aggregation of aromatic or amphiphilic compounds. [22][23][24][25] We have demonstrated the inclusion of 1-alkyl-3-methylimidazolium (C n mim + ) type of ionic liquids in SCXn 26 and unraveled the alteration of the binding thermodynamics with the length of the 1-alkyl substituent on the methylimidazolium moiety. 27,28 When the aliphatic 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 4 chain was composed of n = 12, 14 or 16 C atoms, C n mim + cations and SCX6 spontaneously organized to spherical nanoparticles (NPs) possessing dense multilayered structure and 7:1 stoichiometry.…”