Unveiling the formation 1 : 2 supramolecular complexes between cucurbit[7]uril and a cationic calix[4]arene derivative

Abstract

The formation of host–guest complexes between cucurbit[7]uril (CB7) and a tetracationic calix[4]arene derivative in the so-called cone conformation was investigated by 1H NMR, DOSY NMR, isothermal titration calorimetry and ESI-MS.

Cucurbit[7]uril‐mediated Histidine Dimerization: Exploring the Structure and Binding Mechanism

“…Other examples involve the trapping of an amino group at the carbonyl portal through the formation of iondipole interactions; however, in these cases, the hydrophobic part of the ligand is located outside of the cavity. [36,37] His binds weakly to the CB7 cavity; however, it readily crystallises as a complex in monoclinic or orthorhombic space groups. The crystal structures of D-His (1), L-His (2), and DL-His (3) were obtained.…”

“…In these cases, the positions of the two ligands inside the cavity were predicted based on the reaction mechanism and resulting product. Other examples involve the trapping of an amino group at the carbonyl portal through the formation of ion‐dipole interactions; however, in these cases, the hydrophobic part of the ligand is located outside of the cavity [36,37] . His binds weakly to the CB7 cavity; however, it readily crystallises as a complex in monoclinic or orthorhombic space groups.…”

Evaluation of the supramolecular interaction of Congo red with cucurbiturils using mass spectrometry and spectroscopic methods

“…The supramolecular interaction between cucurbiturils and CR was first evaluated by ESI-MS. ESI-MS has been used to study the formation of cucurbituril host-guest complexes 47 and their aggregates 48 as well as the interaction between negative ions and the outer surface hydrogens of these molecular containers. 49 Initially, the formation of complexes between CR and both macrocycles under positive polarity was evaluated.…”

Supramolecular Chemotherapy with Cucurbit[n]urils as Encapsulating Hosts

“…The compounds formed are named cucurbituril because of their resemblance to a round gourd or a pumpkin in shape. In the CB­[ n ] molecule the oxygen atoms of the polarized carbonyl groups are located along the top and bottom regions thus forming portals for the entry and exit of a guest molecule, with the same height of 9.1 Å for all its units but differ in their exterior and interior diameters. , The electronegative carbonyl units at the top and the hydrophobic cavity in the middle characterize the structure of CB­[ n ] containers. These structural and electronic properties enable them to encapsulate a wide range of guest molecules through noncovalent interactions like H-bonding, hydrophobic interactions, donor–acceptor complexation, metal coordination interactions, and π–π stacking. − The various physical parameters observed for CB­[ n ] units are shown in Table .…”