On‐Surface Synthesis of Chiral Graphene Nanoribbon Segments via the Quarter‐Anthryl on Au(111) Surface

Abstract

Quarteranthene is predicted to manifest nontrivial edge states as the competition from the hybridization of localized frontier states and the Coulomb repulsion between valence electrons, which hosts much research potential in memory, spintronic devices fabrication, and quantum computation. The fabrication of ribbon‐like structures with up‐mentioned edge states, such as chiral graphene nanoribbon, possesses a high significance in the topological phase transition investigation. However, the synthesis of chiral graphene nanoribbon is limited in reactive substrate or with the edge‐brominated precursor. Here, the fabrication of quarteranthene and its chiral graphene nanoribbon segment on Au(111) substrate is reported. A combined bond‐resolved scanning tunneling microscopy, noncontact atomic force microscopy characterization, and corresponding density functional theory calculations confirm the chemical structure of fabricated products on the Au(111) substrate. The detailed analysis of the laterally extended products reveals that the lateral‐extended structures are acquired via the linkage of the hydrocarbon quarter‐anthryl. In addition, several strategies are used to modulate the yield of quarteranthene and its lateral‐extended products. These findings provide a new insight into the lateral extension strategy on metal substrates and provide another possible fabrication strategy of chiral graphene nanoribbons on the relative inert Au(111) substrate.

Length‐Dependent Magnetic Evolution of Anthenes on Au(111)

“…Chemie centers from the (4,7)-NG are not isolated (Figure S6, S7). The combination of previous simulations [38] and observed Kondo resonance indicated (4,7)-NG hosts the net spin of S = 1/2 on Au(111).…”

“…Furthermore, 7-AGNR, considered an upsized (n,7)-NG, experiences slight upshifts of the end states because of hole doping on Au(111), as indicated in Figure 3a. [36][37][38] Calculated charge density difference shows a modest charge transfer of 1.2 e À and 0.85 e À from optimized (4,7)-and (3,7)-NG to substrate (Figure S8). The different line shapes from the H-passivated (4,7)-NG and additional H atom removed (4,7)-NG indicate two spin c, d) STM images obtained before and after tip manipulation of (3,7)-NG (V = À 0.2 V, I = 300 pA).…”

“…In our previous study, we speculated that the frontier orbitals of (4,7)-NG are merged together as the limited energy resolution on the Au(111) substrate. [38] We performed the dI/dV maps near the Fermi level to fit with the simulated LDOS maps from frontier orbitals and obtained the frontier orbitals located at À 40 mV (SOMO) and 60 mV (SUMO), respectively. The electronic structure and the frontier gap (dash lines) indicated that the frontier gap decreased to the Fermi level (from 1.78 eV via 0.29 eV to 0.1 eV [38] ) with the increasing size of the anthenes, enabling the charge transfer to switch the ground state.…”

Length‐Dependent Magnetic Evolution of Anthenes on Au(111)

“…centers from the (4,7)-NG are not isolated (Figure S6, S7). The combination of previous simulations [38] and observed Kondo resonance indicated (4,7)-NG hosts the net spin of S = 1/2 on Au(111).…”

From Short‐ to Long‐Range Chiral Recognition on Surfaces: Chiral Assembly and Synthesis

“…In this sense, on-surface synthesis has recently attracted significant interest, which is proven to be a powerful technique for the selective construction of tailored chiral covalent architectures on surfaces. [11,[105][106][107][108][109] In this section, two prominent strategies are mainly reviewed for fabricating chiral covalent oligomers/polymers on surfaces: 1) Steric hindrance strategy: selective synthesis of chiral nanoarchitectures through avoiding the formation of achiral products via inter-precursor or intra-polymer steric hindrance; 2) Self-assembly strategy: direct chiral synthesis mediated by chiral transfer from pre-formed ordered chiral self-assembled structures. Additionally, metal surfaces, especially relatively active surfaces such as copper, platinum, and nickel surfaces, could play a catalytic role in the selective synthesis of specific chiral products.…”