Tuning Solid-State Calix[n]arene Supramolecular Assemblies Using Phenanthroline as the Guest Molecule

Abstract

Of the available ligands for the study of molecular recognition by para-sulfonato-calix[n]arene receptors, phenanthroline is proving to a far more versatile moiety than it would have initially been expected. Interactions with two anionic host molecules, para-sulfonatocalix[4]arene and para-sulfonato-calix[8]arene, have been previously examined in depth and described. In this paper, further structural studies concerning supramolecular self-assembly species of unsubstituted calix[6]arene, para-sulfonato-calix[6]arene, para-sulfonato-calix[4]arene, and 25,27-O-di(carboxymethoxy)-calix[4]arene with phenanthroline are reported. Structures of crystalline host−guest complexes were determined by means of X-ray diffraction. Diversity of the chemical makeup of the structures is observed: four structures are cocrystals and the other four are organic salts. In the packing motifs columnar systems are the commonest among those observed.

Host–Guest Complexation of the para-Sulfonato-calix[4]arene Receptor with Biomolecules

“…Symmetry expansion of the inclusion complex reveals the formation of a shifted capsule incorporating four guest cations (Figure a). Similar arrangements were observed in complexes of C4S with 1,10-phenanthroline. , …”

“…Similar arrangements were observed in complexes of C4S with 1,10-phenanthroline. 29,30 Inclusion of th e2-aminobenzimidazolium (X) cation is stabilized by C−H•••π interaction Molecular arrangement in crystal 1 is close to layered (Figure 5). The most hydrated areas in the crystal are located near the sulfonate groups of calixarenes.…”

Insights into molecular recognition from the crystal structures of p-tert-butylcalix[6]arene complexed with different solvents

“…The calix [n]arene molecular skeleton consists of a series of phenol rings linked by methylene groups, and structural variants can be obtained by changing the bridging unit or the number of phenolic hydroxyl functionalities. Owing to their flexible and geometrically variable interior cavity, which is large enough to accommodate one or more smaller molecules, calix [n]arenes can function as molecular containers or host molecules (Liao et al, 2009;Dalgarno et al, 2006;Les ´niewska et al, 2019). The formation of their host-guest complexes is stabilized by intermolecular forces, such as ionic interactions, hydrogen bonding,interactions, hydrophobic forces and van der Waals forces.…”

Two Hg(II)-Based Macrocycles Offering Hydrogen Bonding Cavities: Influence of Cavity Structure on Heterogeneous Catalysis

“…Coordination-driven supramolecular self-assemblies are at the pinnacle of supramolecular chemistry. Such a fact is not only related to the presence of well-defined cavities such molecular assemblies offer but also due to the possibility to fine-tune these cavities. − Several such molecular assemblies have been effectively used in host–guest chemistry, − sensing, − drug delivery, − stabilizing reactive intermediates ,− and organic transformations. − Extensive efforts have been made to synthesize assorted molecular assemblies that show remarkable properties. , Efforts vary from the construction of molecular assemblies offering hydrophobic interior space, − and examples include various covalent bonding based assemblies with the objective to tune the cavity structure to suit an application. Efforts have also been made to construct metal–ligand coordination driven molecular assemblies that rely on the geometrical parameters of both metal(s) and ligand(s). − In such molecular assemblies, the interior space has been designed to offer hydrophobic ,− as well as hydrophilic functional groups.…”