N,N'-Disubstituted methylenediimidazolium salts allow the formation of flexible inclusion complexes with beta-cyclodextrin, cucurbit[7]uril, tetrapropoxycalix[4]arene, and dibenzo-24-crown-8 ether. Due to the salt nature of the imidazolium guest, the counterion largely determines its solubility in a given solvent. Moreover, by the judicious choice of the imidazolium substituents, inclusion complexes of guest salts were obtained with a variety of macrocyclic hosts, and the binding parameters of the inclusion were determined for each complex.

A new templating motif for the formation of [2]pseudorotaxanes is described in which T-shaped axles with a benzimidazolium core and aromatic substituents at the 2-, 4-, and 7-positions interact with [24]crown-8 ether wheels ([24]crown-8, dibenzo[24]crown-8, and dinaphtho[24]crown-8). The T-shape greatly enhances the association between axle and wheel when compared to simple imidazolium or benzimidazolium cations. A series of interpenetrated molecules are characterized by (1)H NMR spectroscopy and single crystal X-ray crystallography.

Condensation of an aldehyde appended benzimidazolium cation with a 1,2-benzenediamine in the presence of a crown ether allows formation of a second benzimidazole group and the facile synthesis of a [2]rotaxane molecular shuttle. The ease of this reaction and the versatility of the initial templating interaction between the benzimidazolium cation and crown ether allows for the preparation of [2] rotaxane molecular shuttles with crown ether macrocycles of various shapes and sizes. The synthesis and dynamic properties of a set of five [2]rotaxane molecular shuttles are described including the first examples of rotaxanes containing the larger macrocycles dibenzo[30]crown-10 (DB30C10) and bismeta-phenylene-[26]crown-8 (BMP26C8).

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.

A new family of dialkyl(1,4-phenylene)diimidazolium salts has been synthesized. Salts containing triflate and bis(trifluoromethanesulfonyl)imide anions and different alkyl chains have been prepared. The molecular structures of didodecyl(1,4-phenylene)diimidazolium triflate and bis(trifluoromethylsulfonyl)imide salts were determined by single crystal X-ray diffraction, and the mesomorphic and ionic conducting properties of all these compounds were investigated and are reported here.