Stimuli‐Responsive Topological Transformation of a Molecular Borromean Ring via Controlled Oxidation of Thioether Moieties

A Cp*‐Rh based D‐shaped binuclear metallacycle and a template‐free molecular Borromean ring (BR) were obtained in high yield using the semi‐rigid thioether dipyridyl ligand 1,4‐bis[(pyridin‐4‐ylthio)methyl]benzene (Bptmb). The topological transformation from a binuclear metallacycle and a BR to tetranuclear metallacycles was realized via the controlled oxidation of thioethers. The strategy used in this work can be regarded as a new form of stimuli‐responsive post‐synthesis modification (PSM). The controlled oxidation from thioether to sulfoxide and sulfone groups is a new post‐synthetic modification to achieve the stimuli‐responsive structural transformation from the molecular Borromean ring to tetranuclear metallacycles.