An electrochemically controlled supramolecular zip tie based on host–guest chemistry of CB†
Three molecular threads incorporating two viologen units attached by an oligo-ethylene glycol chain of variable length and an electron rich naphthalene moiety were prepared. The internal viologen unit is connected to the naphthalene by a rigid linker that prevents the simultaneous complexation of these systems. The axle with the shortest chain (14+) in the presence of CB placed the chain inside the macrocycle in aqueous media. In contrast, the longer chains in 24+ and 34+ allow locating the terminal viologen and the electron rich unit inside the cavity. Upon reduction of the bipyridinium salts, the system behaves like a zip tie relaxing the chain as a consequence of the insertion of both radical cation moieties within the CB and making these switches as potential components for molecular machinery.
- This article is part of the themed collection: Supramolecular chemistry in OBC