Synthesis of Interlocked and Non‐Interlocked Deca(para‐phenylene) Derivatives by Ni‐mediated Biaryl Coupling

Abstract

Oligo(para‐phenylene) (PPn) is a compound composed of directly connected 1,4‐phenylene moieties. The synthesis of PPn composed of six or more phenylene moieties with no substituent at the internal phenylene moiety has been challenging because of its low solubility. Herein we synthesized oligo(para‐phenylene)[2]rotaxanes, including a deca(para‐phenylene)[2]rotaxane, with a defined number of phenylene moieties. Biaryl coupling of iodoarenes mediated by macrocyclic dibenzodihydrophenanthroline‐Ni complex was utilized for the first time to synthesize the [2]rotaxanes. Compared to the non‐interlocked deca(para‐phenylene), the deca(para‐phenylene)[2]rotaxane showed higher solubility. The properties of the oligo(para‐phenylene)[2]rotaxanes and non‐interlocked oligo(para‐phenylene)s were analyzed by spectroscopic methods.

Formation of a Metallomacrocycle Possessing Nitrogen Donors Assembled in the Cavity and Unique Water Clusters

“…In the crystal of [ 1 Ni 3 ], unique pentagonal prism clusters of water molecules were found formed by hydrogen bonding with the metal-free bpy nitrogen atoms. This metallomacrocycle is expected to be useful for the molecular recognition of guest molecules based on hydrogen bonding − and for the formation of further supramolecular structures such as rotaxanes. − The ordered water clusters inside the binding pockets of proteins and artificial hosts are considered to play an important role in the entropy-driven molecular binding; thus, this study suggests the utility of [ 1 Ni 3 ] in the molecular recognition. Moreover, by taking the stepwise approach to bind another metal ion to the bpy units of [ 1 Ni 3 ], various heteromultinuclear complexes that cannot be obtained by simple simultaneous mixing of the ligand H 6 1 and two kinds of metal salts become accessible.…”