On-Surface Synthesis of Ni-Porphyrin-Doped Graphene Nanoribbons.

On-surface synthesis of functional molecular structures provides a route to the fabrication of materials tailored to exhibit bespoke catalytic, (opto)electronic, and magnetic properties. The fabrication of graphene nanoribbons via on-surface synthesis, where reactive precursor molecules are combined to form extended polymeric structures, provides quasi-1D graphitic wires that can be doped by tuning the properties/composition of the precursor molecules. Here, we combine the atomic precision of solution-phase synthetic chemistry with on-surface protocols to enable reaction steps that cannot yet be achieved in solution. Our focus of this work is the inclusion of porphyrin species within graphene nanoribbons to create porphyrin-fused graphene nanoribbons. A combination of scanning tunneling microscopy and photoelectron spectroscopy techniques is used to characterize a porphyrin-fused graphene nanoribbon formed on-surface from a linear polymer consisting of regularly spaced Ni-porphyrin units linked by sections of aryl rings which fuse together during the reaction to form graphitic regions between neighboring Ni-porphyrin units.