Adsorption and self-assembling of a norbornadiene derivative on Au(1 1 1)

The norbornadiene-quadricyclane photoswitch is a promising example of molecular solar thermal systems capable of energy conversion, storage and release. We present a scanning tunneling microscopy and spectroscopy study of a symmetric NBD-COOMe derivative adsorbed on the Au(1 1 1) surface, supported by density functional theory simulations. We observe the formation of ordered self-assembled islands of NBD-COOMe on the gold surface, driven by intermolecular van der Waals interaction, which become disordered and gradually desorb upon increasing the surface temperature. After annealing at 200 °C, a few adsorbed molecules show a different appearance and electronic structure suggesting the formation of single metalorganic complexes of NBD-COOMe with gold adatoms.