RESUMEN
Borophenes have sparked considerable interest owing to their fascinating physical characteristics and diverse polymorphism. However, borophene nanoribbons (BNRs) with widths less than 2 nm have not been achieved. Herein, we report the experimental realization of supernarrow BNRs. Combining scanning tunneling microscopy imaging with density functional theory modeling and ab initio molecular dynamics simulations, we demonstrate that, under the applied growth conditions, boron atoms can penetrate the outermost layer of Au(111) and form BNRs composed of a pair of zigzag (2,2) boron rows. The BNRs have a width self-contained to â¼1 nm and dipoles at the edges to keep them separated. They are embedded in the outermost Au layer and shielded on top by the evacuated Au atoms, free of the need for post-passivation. Scanning tunneling spectroscopy reveals distinct edge states, primarily attributed to the localized spin at the BNRs' zigzag edges. This work adds a new member to the boron material family and introduces a new physical feature to borophenes.
RESUMEN
Transition-metal carbides have sparked unprecedented enthusiasm as high-performance catalysts in recent years. Still, the catalytic properties of copper carbide remain unexplored. By introducing subsurface carbon to Cu(111), a displacement reaction of a proton in a carboxyl acid group with a single Cu atom is demonstrated at the atomic scale and room temperature. Its occurrence is attributed to the C-doping-induced local charge of surface Cu atoms (up to +0.30â e/atom), which accelerates the rate of on-surface deprotonation via reduction of the corresponding energy barrier, thus enabling the instant displacement of a proton with a Cu atom when the molecules adsorb on the surface. This well-defined and robust Cuδ+ surface based on subsurface-carbon doping offers a novel catalytic platform for on-surface synthesis.
RESUMEN
Ullmann coupling of 4,4â³-dibromo-p-terphenyl (DBTP) thermally catalyzed on a Ag(111) surface was studied by scanning tunneling microscopy. Detailed experimental measurement shows that the Ullmann coupling reaction pathways of DBTP molecules can be controlled by pre-self-assembly, and the dissymmetric dehalogenation reaction is realized. Moreover, self-assembly of the reactants in a rectangular network undergoes a dissymmetric debromination transfer to a newly observed rhombic network formed by organometallic dimers prior to the formation of longer symmetric organometallic intermediates on a Ag(111) surface, while the ladder assembled phase is more likely to induce the symmetric debromination reaction and converts into the symmetric organometallic intermediate. These findings help us to understand the essentials of the dissymmetric dehalogenation reaction that originated from a symmetric compound and pave new avenues for advancing the emerging field of on-surface synthesis.
RESUMEN
From the combination of STM imaging and DFT calculations, we show that both alkali metal and halogens interact with different sites of the target molecules resulting in structural formation in a synergistic way. The elementary metal-organic motifs are connected by Cl in a variety of fashions demonstrating structural diversity.