Self‐assembly of a [2]pseudorotaxane complex by the threading of a nitrobenzimidazol‐based guest on dibenzo‐24‐crown ether host

A new derivative of the previously reported 1,2‐bis(benzimidazol‐2‐yl)ethane motif, cation [1H 2 ] 2+ , was synthesized under microwave irradiation and fully characterized by solution NMR, high‐resolution mass spectrometry , cyclic voltammetry and X‐ray crystallography. This cation presents a linear geometry and incorporates nitro substituents as electrochemical handles. In solution, cation [1H 2 ] 2+ , is capable of threading the cavity of dibenzo‐24‐crown‐8 ether host (DB24C8) giving rise to a [2]pseudorotaxane complex [1H 2 ⊂DB24C8] 2+ , regardless of the counterion, [CF 3 SO 3 ] − or [CF 3 COO] − . The interpenetrated structure of [1H 2 ⊂DB24C8] 2+ was proven by solution NMR and X‐ray crystallography. This host–guest complex is held together by several non‐covalent interactions, such as hydrogen bonding and ion‐dipole. An electrochemical study of [1H 2 ] 2+ in the presence of variable amounts of DB24C8 was performed; due to the irreversible redox behavior of cation [1H 2 ] 2+ , it was not possible to electrochemically control the association/dissociation process with DB24C8. Copyright © 2014 John Wiley & Sons, Ltd.