A New Member of the Inverted Cucurbit[n ]uril Family

A facile cucurbit[8]uril-based porous assembly: utilization in the adsorption of drugs and their controlled release

Cucurbit[n]urils (Q[n]s) are essential members of the supramolecular organic framework family owing to their distinct structure.

A Study of the Interaction Between Cucurbit[8]uril and Alkyl-Substituted 4-Pyrrolidinopyridinium Salts

The interaction between cucuribit[8]uril (Q[8]) and a series of 4-pyrrolidinopyridinium salts bearing aliphatic substituents at the pyridinium nitrogen, namely 4-(C₄ H₈ N)C₅ H₅ NRBr, where R=Et (g1), n-butyl (g2), n-pentyl (g3), n-hexyl (g4), n-octyl (g5), n-dodecyl (g6), has been studied in aqueous solution by ¹ H NMR spectroscopy, electronic absorption spectroscopy, isothermal titration calorimetry and mass spectrometry. Single crystal X-ray diffraction revealed the structure of the host-guest complexes for g1, g2, g3, and g5. In each case, the Q[8] contains two guest molecules in a centrosymmetric dimer. The orientation of the guest molecule changes as the alkyl chain increases in length. Interestingly, in the solid state, the inclusion complexes identified are different from those observed in solution, and furthermore, in the case of g3, Q[8] exhibits two different interactions with the guest. In solution, the length of the alkyl chain plays a significant role in determining the type of host-guest interaction present.

Supramolecular self-assemblies of inverted cucurbit[7]uril with biogenic amines

The binding interactions between six biogenic amine guests and the iQ[7] host were investigated. The experimental results have revealed that iQ[7] shows strong binding affinity towards five of the studied biogenic amines, but not histamine, and that the binding sites are different depending on the structure of the biogenic amine.

Study on the Binding Interaction of the α,α',δ,δ'-Tetramethylcucurbit[6]uril With Biogenic Amines in Solution and the Solid State

1H NMR spectroscopy and MALDI-TOF mass spectrometry were utilized to examine the binding interaction of α,α',δ,δ'-tetramethylcucurbit[6]uril (TMeQ[6]) and six biogenic amines (spermine, spermidine, 2-phenethylamine, tyramine, histamine, and tryptamine). Their 1H NMR spectra both at pD = 7 and pD = 3 revealed that four biogenic amines (spermine, spermidine, 2-phenethylamine, and histamine) can fit in the TMeQ[6] cavity, respectively, and other biogenic amines were located outside of the TMeQ[6] portal. In addition, a solid-state evaluation with single-crystal X-ray diffraction analysis showed the binding interaction of spermine, spermidine, 2-phenethylamine, and tyramine with TMeQ[6].