Molecule of the Month
June 2016
Breaking Aromaticity at High Pressure

On compressing the crystal form of syn-1,6:8,13-Biscarbonyl[14]annulene, one of the two resonant configurations localizes. This is evident from the molecular geometries measured or calculated at several pressures (up to 10 GPa) and from the experimental electron density distribution determined for the first time in a crystal at high pressure.

This work was carried out in the research group of PD Dr. Piero Macchi, in cooperation with Dr. Nicola Casati (Paul Scherrer Institute).


  • N. Casati, A. Kleppe, A. P. Jephcoat, P. Macchi;
    "Putting pressure on aromaticity along with in situ experimental electron density of a molecular crystal"
    Nature Communications, 2016, 7, 10901/1-8; doi:10.1038/ncomms10901.