Chemical and physical properties of graphenes are naturally determined by its edge structures. Chemical functionalization is one of promising strategy to modulate the peripheral structure of graphenes. As a molecular-level model system, large polycyclic aromatic hydrocarbons (PAHs), i.e. so-called nanographenes, can be chemically modified through edge functionalization. Although the synthetic protocols for edge substitution of nanographenes are well developed, the regioselective chemical functionalization of nanographenes remains an enormous challenge, most likely due to the lack of suitable synthetic protocols. Here we show a regioselective peripheral thiolation of nanographenes by selective thiolation of perchlorinated nanographene. Based on two model perchlorinated nanographenes C₄₂Cl₁₈ and C₆₀Cl₂₄, we found the chlorines at the vertex of nanographenes are regioselectively substituted by the thiophene-2-thiol, which shows the first case of selective functionalization of nanographenes. The rest chlorines at the bay positions provide the platform for further functionalization. It enables us to design and produce a series of edge functionalized nanographenes.

Figure 1. Regioselective thiolation of perchorinated graphene