Detection of Intramolecular Interactions and Molecular Motion in Catenanes by Pulse Voltammetry Methods

✍ Scribed by Renata Bilewicz; Bohdan Korybut-Daszkiewicz; Agnieszka Rogowska; Jadwiga Szydłowska; Agnieszka Wiȩckowska; Sławomir Domagała; Krzysztof Woźniak

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 148 KB
• Volume: 17
• Category: Article
• ISSN: 1040-0397
• DOI: 10.1002/elan.200503287

✦ Synopsis

Abstract

Pulse voltammetries allowed to demonstrate that interlocking of a dibenzocrown ether with the homo‐ or heterodinuclear bismacrocyclic transition metal complexes leads to increased stability of the mixed‐valence state. Based on the shape of differential pulse curves, the value of comproportionation constants were obtained, showing that the observed effect was larger for the dinickel (d^8^d^8^) than for the dicopper (d^9^d^9^) catenane. Nonequivalent copper environments in copper catenane were detected by ESR technique. If both of the coordinated ions were identical, the translocation of the crown ether moiety from one site to the other produced the same catenane arrangement. However, intertwining of the dibenzo‐24‐crown‐8 with a heterodinuclear bismacrocyclic complex lead to two possible arrangements, where the π‐electron‐rich benzene rings were located in the vicinity of either the copper or nickel‐complexing macrocycle, depending on the oxidation state of the coordinated ions. Reverse pulse voltammetry with varying initial potentials, E~i~, was found to be a convenient tool to follow these subtle changes of electrochemical behavior of redox centers caused by changed interactions inside the molecule.