  The activation and subsequent covalent coupling of polycyclic aromatic
hydrocarbons (PAHs) are of great interest in fields like chemistry, energy,
biology, or health, among others. However, this is not a trivial process. So
far, it is based on the use of catalysts that drive and increase the efficiency
of the reaction. Here, we report on an unprecedented method in which the
dehydrogenation and covalent coupling is thermally activated in the presence of
atomic hydrogen and a surface. This mechanism, which requires of the
superhydrogenation of the PAHs, has been characterized by high-resolution
scanning tunnelling microscopy (STM) and rationalized by density functional
theory (DFT) calculations. This work opens a door toward the formation of
covalent, PAH-based, macromolecular nanostructures on low-reactive surfaces,
thus facilitating its applicability.
