Selective activation of four quasi-equivalent C-H bonds yields N-doped graphene nanoribbons with partial corannulene motifs

Abstract

Selective C-H bond activation is one of the most challenging topics for organic reactions. The difficulties arise not only from the high C-H bond dissociation enthalpies but also the existence of multiple equivalent/quasi-equivalent reaction sites in organic molecules. Here, we successfully achieve the selective activation of four quasi-equivalent C-H bonds in a specially designed nitrogen-containing polycyclic hydrocarbon (N-PH). Density functional theory calculations reveal that the adsorption of N-PH on Ag(100) differentiates the activity of the four ortho C(sp³) atoms in the N-heterocycles into two groups, suggesting a selective dehydrogenation, which is demonstrated by sequential-annealing experiments of N-PH/Ag(100). Further annealing leads to the formation of N-doped graphene nanoribbons with partial corannulene motifs, realized by the C-H bond activation process. Our work provides a route of designing precursor molecules with ortho C(sp³) atom in an N-heterocycle to realize surface-induced selective dehydrogenation in quasi-equivalent sites.