On‐Surface Assembly of Hydrogen‐ and Halogen‐Bonded Supramolecular Graphyne‐Like Networks

Abstract

Demonstrated here is a supramolecular approach to fabricate highly ordered monolayered hydrogen‐ and halogen‐bonded graphyne‐like two‐dimensional (2D) materials from triethynyltriazine derivatives on Au(111) and Ag(111). The 2D networks are stabilized by N⋅⋅⋅H−C(sp) bonds and N⋅⋅⋅Br−C(sp) bonds to the triazine core. The structural properties and the binding energies of the supramolecular graphynes have been investigated by scanning tunneling microscopy in combination with density‐functional theory calculations. It is revealed that the N⋅⋅⋅Br−C(sp) bonds lead to significantly stronger bonded networks compared to the hydrogen‐bonded networks. A systematic analysis of the binding energies of triethynyltriazine and triethynylbenzene derivatives further demonstrates that the X3‐synthon, which is commonly observed for bromobenzene derivatives, is weaker than the X6‐synthon for our bromotriethynyl derivatives.

Real-space Imaging of the Multiple Halogen Bonds by Ultrahigh-resolution Scanning Probe Microscopy

“…The calculated results suggests that charge transfer between Br-N and Br-H atoms also play an important role, in line with IUPAC recommendations and literature reports. 3,15,41 We infer that the electron density between Br-N and Br-H atoms may also contribute to the bright lines feature observed at nc-AFM images in Figure 2b and 2e, and the higher intensity of electron density between Br-H atoms than that between Br-N atoms results in a brighter line of Br-H bond than that of Br-N bond shown at nc-AFM images.…”

“…The chemical bond is of central interest in the chemistry discipline, and it plays an important role in the construction of both matter and life. In particular, non-covalent bonds are the fundamental basis of supramolecular self-assembly, 1 including hydrogen bonds, 2 halogen bonds, 3 coordination bonds, 4,5 dipole-dipole interactions 6 and so on. [7][8][9] The halogen bond has recently attracted much interest, 10 while the hydrogen bond has been the most studied intermolecular interaction in the past.…”

Realizing Two-Dimensional Spin Arrays on Surfaces via Halogen-Bonding Molecular Self-Assembly

“…DFT-optimized model in Figure 4c shows that six Br atoms form a hexagonal-shaped structure with the bond angle (∂3) of ~119 o and Br-Br distance (d3) of ~3.6 Å. Type-3 halogen bond has been theoretically predicted, 55 and it was recently demonstrated by Maier et al in experiment. 45 We noted that the types of halogen bonds are diverse, which can be employed to realize variable molecular self-assembled structures and thus adjusting the lateral distance of two molecular spins. Here we recorded three different distances between two molecular spins: 13.6 Å, 21.3 Å and 23.1 Å, respectively.…”

“…[36][37][38][39][40][41][42] In particular, by employing high-resolution surface characterization techniques, halogen bonds have recently been studied and show great promise in mediating highly-ordered supramolecular arrays on surface. [43][44][45][46] In this work, a bromine-terminated perchlorotriphenymethyl radical (3Br-PTM) with net carbon spin was synthesized and thermally-deposited to achieve two-dimensional ordered spin arrays on an insulating bromine monolayer on Au(111). Halogen bonds play an important role in regulating the supramolecular spin arrays formation on surface.…”

Transition Metal and Nitrogen Co‐Doped Carbon‐based Electrocatalysts for the Oxygen Reduction Reaction: From Active Site Insights to the Rational Design of Precursors and Structures

“…Doped Nitrogen atoms, regulating the electronic structure of the MÀ N x /C materials (especially the d electrons of the central metal atom) and electron-transfer characteristics, are essential for adjusting the local coordination environments of the catalysts. [56] Generally, some nitrogen-containing functional groups can coordinate with metal ions under mild conditions, so pre-separated metal ions are difficult to migrate during the high-temperature pyrolysis, thus the active MÀ N x structure is retained in the final catalyst as much as possible. [57] Also, some nitrogen-containing precursors promote the formation of active NÀ C moieties at high density in pyrolytic MÀ N x /C catalysts.…”