A Photochemical/Thermal Switch Based on 4,4′‐Bis(benzimidazolio)stilbene: Synthesis and Supramolecular Properties.

Stilbene derivatives are well‐recognised substructures of molecular switches based on photochemically and/or thermally induced ( E )/( Z ) isomerisation. We combined a stilbene motif with two benzimidazolium arms to prepare new sorts of supramolecular building blocks and examined their binding properties towards cucurbit[ n ]urils ( n =7, 8) and cyclodextrins (β‐CD, γ‐CD) in water. Based on the 1 H NMR data and molecular dynamics simulations, we found that two distinct complexes with different stoichiometry, i. e., guest@β‐CD and guest@β‐CD 2 , coexist in equilibrium in a water solution of the ( Z )‐stilbene‐based guests. We also demonstrated that the bis(benzimidazolio)stilbene guests can be transformed from the ( E ) into the ( Z ) form via UV irradiation and back via thermal treatment in DMSO.