Real-space visualization of sequential debromination of polybrominated benzenes on Ag(111)

Abstract

By a combination of scanning tunneling microscopy (STM) imaging and density functional theory (DFT) calculations, dehalogenation processes of symmetric polyhalogenated benzenes were explored on Ag(111), and a series of intermediate...

Visualizing the Hierarchical Evolution of Aryl–Metal Bonding in Organometallic Nanostructures on Ag(111)

“…As an extension, dehalogenative cyclization has been further realized based on more complicated ortho -dihalo substitutions (Figure S1), resulting in the generation of four- and six-membered ring scaffolds. − In addition, peri -region , and bay -region − substitutions (Figure S1) as well as their combination have been exploited and validated to be useful in producing a variety of ring structures, including six-, eight-, and four-membered ones, respectively, further enriching the toolbox for generating n -membered nonbenzenoid rings with fascinating properties embedded. Specifically, due to the complexity of multiple C–X activation, a single-sided bay -region substitution was shown to be distinct from the double-sided ones in both reaction pathways and products. For the combination of peri - and bay -region substitutions, various organometallic intermediates produced in the evolution process have been visualized to track the reaction pathways.…”

“…A typical Hbased organometallic dimer structure is illustrated in Figure 2b, where two H-motifs are connected together by sharing one bright dot at the junction, suggesting the occurrence of C−Br bonds cleavage and Ag adatom insertion to form C−Ag−C bonds. 11,21,25 Upon further annealing at ∼380 K, longer organometallic oligomers emerged (Figure 2c). A close inspection of a typical H-based organometallic oligomer shows that it is composed of several H-motifs connected by Ag adatoms through "single-legs" (Figure 2d).…”

“…As the metal insertion via C–Br cleavage requires elevated temperatures, the above sample was further annealed at ∼300 K, and the self-assembled structures of H-motifs became less ordered with the majority of the H-motifs coupled via the connection of one “leg” to form staggered oligomers with different numbers of units involved (Figure a). A typical H-based organometallic dimer structure is illustrated in Figure b, where two H-motifs are connected together by sharing one bright dot at the junction, suggesting the occurrence of C–Br bonds cleavage and Ag adatom insertion to form C–Ag–C bonds. ,, Upon further annealing at ∼380 K, longer organometallic oligomers emerged (Figure c). A close inspection of a typical H-based organometallic oligomer shows that it is composed of several H-motifs connected by Ag adatoms through “single-legs” (Figure d).…”