Awkwardly‐Shaped Dimers, Capsules and Tetramers: Molecular and Supramolecular Motifs in C5‐Arylated Chiral Calixsalens

Abstract

A series of novel C‐5 arylated calixsalens synthesized via [3+3] cyclocondensation of trans‐(R,R)‐1,2‐diaminocyclohexane with 2‐hydroxyisophthalaldehyde derivatives are presented. The nonsymmetrical aryl substituents of the 1‐naphthyl type may act as switches opening (ON conformation) or closing (OFF conformation) the macrocycle cavity. This group of macrocycles, depending on the kind of aryl substituent, is characterized by a large variety of supramolecular architectures. Whereas the substitution of the calixsalen skeleton by 2,5‐dimethoxybenzene groups promotes the formation of head‐to‐head capsules, the presence of a 3,5‐dimethylbenzene group favors the tail‐to‐tail dimers. Introduction of 2‐naphthyl substituents, in turn, results in the formation of a supramolecule consisting of four monomers that exists only in the solid state. Such arrangements of macrocycles generate a truncated tetrahedron shaped cavity never previously observed for this type of macrocyclic compounds.

Imine- and Amine-Type Macrocycles Derived from Chiral Diamines and Aromatic Dialdehydes

“…They can act as hosts for small organic guest molecules, form dimers and capsules or self-associate into larger structures. The formation of various noncovalent aggregates of these macrocycles was demonstrated by Kwit, Janiak and others for solid, liquid, and gas phases [88][89][90][91][92][93][94][95].…”

One‐Step Construction of the Shape Persistent, Chiral But Symmetrical Polyimine Macrocycles

“…In this case, four macrocycles, held together by the weak C−H⋅⋅⋅O and C−H⋅⋅⋅π intermolecular interactions, formed supermolecule through spherical arrangement (Figure c). Such an arrangement generates a truncated tetrahedron shaped cavity of the mean diameter equals to 8.5 Å that corresponds to 733 Å 3 of solvent accessible space …”

“…Despite the highest available C 3 symmetry, the extreme all ‐ ON and all ‐ OFF conformers of M4j are energetically not preferred and the lowest energy conformer of M4j is characterized by the partially open structure. (Figure ) …”

Synthesis and characterization of two metallo-hydrogen-bonded organic frameworks with diverse structures and properties

“…Notably, pioneering researchers have reported the synthesis of a macrocycle that contains a coordinated pocket capable of securely encapsulating three metal ions, particularly Cu( ii ) and Zn( ii ), due to macrocyclic and chelating effects. 42–45…”

“…Notably, pioneering researchers have reported the synthesis of a macrocycle that contains a coordinated pocket capable of securely encapsulating three metal ions, particularly Cu(II) and Zn(II), due to macrocyclic and chelating effects. [42][43][44][45] Additionally, charge-balanced anions are present around the resulting complex. 46,47 Inspired by these studies, we synthesized a macrocyclic ligand (L) functionalized with three peripheral carboxylic acids using the synthetic pathway depicted in Scheme 1.…”