The design and self-assembly of a pyridine-containing [2]catenane

Abstract

A bispyridine-containing crown ether (6) has been incorporated, along with bis(paraquat-p-phenylene), into a [2]catenane 3.4PF 6 using a self-assembly approach. The incorporation of pyridine units allows one of the noncovalent interactions-hydrogen bonding-that determines (i) the efficiency of the template-directed synthesis and (ii) the dynamic properties of the [2]catenane, to be assessed for its relative importance as a recognition feature during and after the formation of 3.4PF 6 . The pyridine-containing [2]catenane has also been used, for the first time, to determine the activation barrier to a previously predicted, yet unobserved, site-exchange process-'rocking'-within the [2]catenane structures in the solution state.