Molecule of 10 fused benzene rings in a row has been made for the first time

Kr ger et al 2017 Angewandte Chemie International Edition 2 fig 1

Source: © Wiley

Decacene, a molecule comprising 10 linearly fused benzene rings,1 has become the longest acene ever made, seven years after the nine-ring nonacene was first detected.2

Naphthalene and anthracene – consisting respectively of two and three fused benzene rings – are well known and stable compounds. Higher acenes, however, become more unstable the longer they get; those beyond pentacene have proven particularly tricky to synthesise. The seven-ring heptacene was first isolated earlier this year, a feat that took 75 years to accomplish.3

A team around Francesca Moresco from the Technical University Dresden, Germany, and Diego Peña from the University of Santiago de Compostela, Spain, have now synthesises decacene by plucking oxygen off a precursor that was immobilised on a gold surface. Scanning tunnelling microscopy at -268°C then revealed the elusive acene as a caterpillar-like structure.

Although decacene is currently too unstable for any practical applications, researchers are interested in exploring its electronic properties – pentacene, for example, is a semiconductor used in organic electronics.