[20a-311-1~12] 17.2 Graphene

[20a-311-7] Mechanisms of Covalent Coupling Reaction of Dibromofluoranthene on Au(111)

〇Akihiro Nagoya¹, Ohba Nobuko¹, Hiroyuki Tetsuka¹ (1.TCRDL)

Keywords:graphene nanoribbon, DFT calculations, reaction path analysis

The reaction mechanism of on-surface coupling of 7,10-dibromofluoranthene (Br₂FL) on Au(111) was studied on the basis of density functional theory (DFT) calculations, as a possible route for fabricating graphene nanoribbons (GNRs) including pentagonal rings. The reaction path and the energy barriers of debromination, radical coupling, and diffusion processes were investigated. The rate-limiting step was radical coupling associated with formation of a gold-metallic intermediate, which is rarely observed on Au(111), as a consequence of the steric repulsion between two radicals and that between the radicals and the substrate. The results suggest that Br₂FL is preferable as the precursor of the coupling reaction to fabricate well-defined GNRs including pentagonal rings.