Supramolecular Macrocycles Research Articles

Supramolecular macrocycles self-assembled by phenanthroline–Cu(I) and sugar–boronic acid interactions

Two kinds of ligand which have two phenanthroline groups linked by a C 2-symmetrical chiral tetrol were synthesized by a boronic acid–diol interaction. It was shown that these ligands form unique dinuclear chiral macrocycles by a Cu(I)–phenanthroline interaction. The results indicate that a novel supramolecular system can be exploited by combination of the Cu(I)–phenanthroline interaction with the boronic acid–diol interaction.

Molecular and Supramolecular Synthesis with Dibenzofuran‐Containing Systems

AbstractThe template‐directed syntheses of two new tetracationic cyclophanes, cyclobis(paraquat‐2,8‐dibenzofuran) and cyclobis(paraquat‐3,7‐dibenzofuran), incorporating dibenzofuran subunits has been accomplished. Initially, the cyclophanes were self‐assembled around a macrocyclic polyether template, bis‐p‐phenylene[34]crown‐10 (BPP34C10), to form catenanes: the mechanical bond order of the catenane formed determined the requisite “amacrocyclic” templates for synthesis of the free cyclophane. X‐ray crystallography shows that both of the cyclophanes possess rectangular covalent frameworks. Furthermore, these cyclophanes form self‐assembled tapes in the solid state, since the dibenzofuran moieties have a tendency to associate with each other through crossed ∞–∞ stacks. The dibenzofuran‐containing catenanes also form two‐dimensional supramolecular arrays in the solid state on account of extended ∞–∞ stacking interactions. In addition, the serendipitous discovery of a plerotopic tecton (consisting of a dibenzofuran nucleus covalently linked from the 2‐ and 8‐positions by methylene groups to 4,4′‐pyridylpyridinium (hydrogen bond acceptor) and protonated bipyridinium (hydrogen bond donor) units) has been made. The tecton dimerizes in the solid state to form a supramolecular macrocycle, since its complementary hydrogen bonding sites are oriented in a horseshoelike fashion by the 2,8‐disubstituted dibenzofuran unit. However, this superstructure is not retained in the 1:1 complex of the tecton with BPP34C10: cocrystallization of the tecton with this crown ether opens the macrocyclic two‐component supermolecule to afford a hydrogen‐bonded pseudopolyrotaxane.

Self-complementary hydrogen bonding heterocycles designed for the enforced self-assembly into supramolecular macrocycles

A series of 2-oxopyrimido[4,5-d] pyrimidin-5(6H)-ones are synthesized that contain a hydrogen bond code that mediates their self-organisation into a hexameric supramolecular macrocylic structure.

Self-assembly of a multi-porphyrin supramolecular macrocycle by hydrogen bond molecular recognition

Three triaminotriazine units bearing two appended porphyrins undergo self-assembly through multiple hydrogen-bonding with three complementary dialkylbarbituric acids yielding a supramolecular macrocycle containing six porphyrins.