Study of the Supramolecular Cooperativity in the Multirecognition Mechanism of Cyclodextrins/Cucurbituril/Disubstituted Diimidazolium Bromides

Abstract

N, N'-Disubstituted methylenediimidazolium bromide salts substituted with two aromatic groups present two different binding sites. In the binary complexes with cyclodextrins (CDs) or cucurbit[7]uril (CB[7]), the macrocycle is always positioned on the external aromatic residues. In the ternary complexes, CB[7] is positioned around the diimidazolium cation, where the external aromatic residue is included in the CD's cavity. The unfavored position of the CB[7] on the cationic site in the ternary complex is the result of its cooperative supramolecular interaction with the cyclodextrin. The obtained ternary complexes possess different interfacial properties, compared to those of the binary complexes. We demonstrate these hypotheses by NMR spectroscopy, ESI-HRMS spectrometry, molecular modeling simulation, and surface tension measurements.

Molecular Selective Binding and Nanofabrication of Cucurbituril/Cyclodextrin Pairs

“…Developing from the above ternary assembly, another successful example of the 1 : 1 : 1 assembly including cucurbiturils and cyclodextrins is designed and constructed (Scheme 5) by mixing N,N'-disubstituted methylenediimidazolium bromide salt, cucurbiturils, and cyclodextrins in stoichiometric proportion (Scheme 5). [37] High resolution mass spectrometric measurements using electrospray ionization demonstrate the formation of 1 : 1 : 1 ternary assembly at 4 mm concentration of each component. Interestingly, by altering the substituents of N,N'-disubstituted methylenediimidazolium templates from phenyl to benzyl groups, the binding position of cucurbituril can be effectively controlled.…”

Rotaxanes Capped with Host Molecules: Supramolecular Behavior of Adamantylated Bisimidazolium Salts Containing a Biphenyl Centerpiece

“…Because the portals of CBs are complementary to those of cyclodextrins, H‐bonds stabilize the ternary aggregates in a pseudorotaxane manner, in which the macrocycles surround one9 or two10 cationic centers. Even non‐ionic polyethyleneglycol has been reported to thread α‐CD or CB6 and α‐CD units in a random order 11…”

Electron Density Shift in Imidazolium Derivatives upon Complexation with Cucurbit[6]uril

“…Bis(imidazolium) dication was also used as a guest, allowing the formation of ternary complexes. [10] In these complexes, one guest molecule is included in both CB7 and b-cyclodextrin macrocycles leading to a cooperative supramolecular interaction between the macrocycles. Many imidazolium compounds are known to behave as ionic liquids (ILs), a class of organic compounds that have found industrial application as designer solvents [11] and catalysts [12] in organic reactions, and media in separation technologies.…”