Knot your usual hydrocarbons

Abstract

The nanocarbon family just got bigger and more complex. Chemists in Japan have created intertwined molecules, including a trefoil knot and interlocked rings known as catenanes, made up entirely of benzene rings (Science 2019, DOI: 10.1126/science.aav5021). This adds mechanically bonded molecules to the menagerie of carbon nanostructures, which includes fullerenes and nanotubes. Mechanical bonds are key to the movement of many types of molecular machines, the construction of which garnered their creators the 2016 Nobel Prize in Chemistry. “Occasionally a molecule is made that just looks impossible. This paper has three,” says David A. Leigh, an expert in topologically complex molecules at the University of Manchester who was not involved in the research. Nagoya University’s Kenichiro Itami and Yasutomo Segawa led the team that created the nanocarbon structures. Previous examples of catenanes and molecular knots typically contain heteroatoms like nitrogen. These heteroatoms are necessary for stitching toget...