A record-breaking polycatenane

Abstract

Through the use of some time-tested chemistry and clever monomer design, chemists led by the University of Chicago’s Stuart J. Rowan have managed to make a record-breaking polycatenane that mechanically links 26 ring-shaped molecules in a single chain. Their branched polycatenanes are even larger, boasting as many as 130 rings in a single mechanically interlocked molecule. The structures could have unusual properties and would allow chemists to see if the flexible behavior seen in strands of metal chain-links also occurs on the molecular scale. Chemists have been dreaming about making these types of polycatenanes ever since the University of Strasbourg’s Jean-Pierre Sauvage hooked two ring-shaped molecules together to make a basic catenane in 1983—a feat for which he shared the 2016 Nobel Prize in Chemistry. Although chemists have managed to make polycatenanes with up to nine rings in a row, making longer chains has proven difficult. “One of the key