Copper(I) Templated Synthesis of a 2,2'-Bipyridine Derived 2-Catenane: Synthetic, Modelling, and X-ray Studies

Abstract

Following molecular modelling employing molecular mechanics and semi-empirical (PM3) calculations as an aid to ligand design, a new copper(i)-containing [2]-catenane has been prepared by the reaction of 6,6′-bis[(4″-formylphenoxy)methyl]-2,2′-bipyridyl with 1,6-hexanediamine in the presence of a copper(i) template, followed by in situ sodium borohydride reduction of the tetra-imine species generated. The corresponding [2]-catenane was obtained as a deep orange crystalline solid. The X-ray structure of this product along with that of the corresponding bis-dialdehyde precursor copper(i) complex have been determined. In the latter case, the structure is pre-organized for catenane formation. The new catenane appears to be the first example of a tetrahedral metal template product incorporating a bis-bipyridyl derivative core. Isolation of the metal-free [2]-catenane has also been achieved following treatment of the copper(i) catenane complex in dimethylsulfoxide with tetrabutylammonium cyanide.