LETTER ▌259 letterModular Synthesis of Monomers for On-Surface Polymerization to Graphene Architectures

On the occasion of the 100th anniversary of the Scholl reaction. Abstract: We developed a modular synthesis of halogenated poly-cyclic aromatic monomers for on-surface polymerization to gener-ate graphene wires, ribbons, and networks. Key words: graphene monomers, graphene nanoribbons, function-alized graphene nanoribbons, graphene wires, hexabenzocoronene, on-surface polymerization Graphene is one of the most promising materials for fu-ture electronic devices. It conducts electrons without heat dissipation, is transparent, strong yet flexible and very light.1 Several methods have been established for the syn-thesis of monolayers of graphene2 although there are from the point of view of a chemist not thoroughly satisfying. Often they lack of means to entirely prevent the develop-ment of second and higher layers, they cannot control edge structures and still struggle with defects that have a strong influence on the behavior of graphene.3 Pure and defect-free graphene does not exhibit a band gap, which is strongly needed for application in electronic de-vices requiring semiconducting materials. This brings up the need for defined band gaps that can be created and Scheme 1 Concept of surface-supported fabrication of graphene architectures by use of a) conventional HBC monomers leading to graphene wires, and b) trapezoidal HBC monomers with two additional benzene rings to fill the gaps yielding graphene nanoribbons