scholarly journals Self-assembly of N-heterocyclic carbenes on Au(111)

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alex Inayeh ◽  
Ryan R. K. Groome ◽  
Ishwar Singh ◽  
Alex J. Veinot ◽  
Felipe Crasto de Lima ◽  
...  
Keyword(s):  
Self Assembly ◽  
Density Functional ◽  
Surface Coverage ◽  
High Mobility ◽  
Heterocyclic Carbenes ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Surface Geometry ◽  
Functional Theory ◽  
Interesting Alternative

AbstractAlthough the self-assembly of organic ligands on gold has been dominated by sulfur-based ligands for decades, a new ligand class, N-heterocyclic carbenes (NHCs), has appeared as an interesting alternative. However, fundamental questions surrounding self-assembly of this new ligand remain unanswered. Herein, we describe the effect of NHC structure, surface coverage, and substrate temperature on mobility, thermal stability, NHC surface geometry, and self-assembly. Analysis of NHC adsorption and self-assembly by scanning tunneling microscopy and density functional theory have revealed the importance of NHC-surface interactions and attractive NHC-NHC interactions on NHC monolayer structures. A remarkable way these interactions manifest is the need for a threshold NHC surface coverage to produce upright, adatom-mediated adsorption motifs with low surface diffusion. NHC wingtip structure is also critical, with primary substituents leading to the formation of flat-lying NHC2Au complexes, which have high mobility when isolated, but self-assemble into stable ordered lattices at higher surface concentrations. These and other studies of NHC surface chemistry will be crucial for the success of these next-generation monolayers.

Understanding molecular self-assembly of a diol compound by considering competitive interactions

2016 ◽  
Vol 18 (39) ◽  
pp. 27390-27395 ◽  
Author(s):  
Oscar Díaz Arado ◽  
Maike Luft ◽  
Harry Mönig ◽  
Philipp Alexander Held ◽  
Armido Studer ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Scanning Tunneling Microscopy ◽  
Self Assembly ◽  
Density Functional ◽  
Competitive Interactions ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Functional Theory ◽  
Chemical Groups

With a combination of scanning tunneling microscopy and density functional theory, effects on molecular self-assembly involving two distinct chemical groups were investigated.

scholarly journals Exploring the Adsorption Mechanism of Tetracene on Ag(110) by STM and Dispersion-Corrected DFT

Crystals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 13 ◽  
Author(s):  
Zhaofeng Liang ◽  
Qiwei Tian ◽  
Huan Zhang ◽  
Jinping Hu ◽  
Pimo He ◽  
...  
Keyword(s):  
Molecular Electronics ◽  
Self Assembly ◽  
Density Functional ◽  
Scanning Tunneling ◽  
Dispersion Force ◽  
Tunneling Microscopy ◽  
Functional Theory ◽  
Silver Substrate ◽  
The Difference ◽  
Low Dimensional

Self-assembled strategy has been proven to be a promising vista in constructing organized low-dimensional nanostructures with molecular precision and versatile functionalities on solid surfaces. Herein, we investigate by a combination of scanning tunneling microscopy (STM) and dispersion-corrected density functional theory (DFT), the adsorption of tetracene molecules on the silver substrate and the mechanism mediating the self-assembly on Ag(110). As expected, ordered domain is formed on Ag(110) after adsorption with adjacent molecules being imaged with alternating bright or dim pattern regularly. While such behavior has been assigned previously to the difference of molecular adsorption height, herein, it is possible to investigate essentially the mechanism leading to the periodic alternation of brightness and dimness for tetracene adsorbed on Ag(110) thanks to the consideration of Van der Waals (vdW) dispersion force. It is demonstrated that the adsorption height in fact is same for both bright and dim molecules, while the adsorption site and the corresponding interfacial charge transfer play an important role in the formation of such pattern. Our report reveals that vdW dispersion interaction is crucial to appropriately describe the adsorption of tetracene on the silver substrate, and the formation of delicate molecular architectures on metal surfaces might also offers a promising approach towards molecular electronics.

scholarly journals Highly ordered N-heterocyclic carbene monolayers on Cu(111)

2021 ◽  
Author(s):  
Eloise Angove ◽  
Federico Grillo ◽  
Herbert Früchtl ◽  
Alex Veinot ◽  
Ishwar Singh ◽  
...  
Keyword(s):  
Self Assembly ◽  
Density Functional ◽  
Triangular Array ◽  
Scanning Tunneling ◽  
Long Range Order ◽  
Aromatic Rings ◽  
Tunneling Microscopy ◽  
Functional Theory ◽  
Resolution Electron ◽  
Electron Energy Loss

The benzannulated N-heterocyclic carbene, 1,3-dibenzylbenzimidazolylidene (NHCDBZ) forms large, highly ordered domains when adsorbed on a Cu(111) surface under ultrahigh vacuum conditions. A combination of scanning tunneling microscopy (STM), high resolution electron energy loss spectroscopy (HREELS) and density functional theory (DFT) calculations reveals that the overlayer consists of vertical benzannulated NHC moieties coordinating to Cu adatoms. Long range order results from the placement of the two benzyl units from a single NHC on opposite sides of the benzimidazole moiety, with the planes of their aromatic rings approximately parallel to the surface. The organization of three surface-bound benzyl substituents from three different NHCs into a triangular array controls the formation of a highly ordered Kagome-like lattice on the surface. This study illustrates the importance of dispersive interactions to control the binding geometry and self-assembly of the NHC.

scholarly journals Highly ordered N-heterocyclic carbene monolayers on Cu(111)

2021 ◽  
Author(s):  
Eloise Angove ◽  
Federico Grillo ◽  
Herbert Früchtl ◽  
Alex Veinot ◽  
Ishwar Singh ◽  
...  
Keyword(s):  
Self Assembly ◽  
Density Functional ◽  
Triangular Array ◽  
Scanning Tunneling ◽  
Long Range Order ◽  
Aromatic Rings ◽  
Tunneling Microscopy ◽  
Functional Theory ◽  
Resolution Electron ◽  
Electron Energy Loss

The benzannulated N-heterocyclic carbene, 1,3-dibenzylbenzimidazolylidene (NHCDBZ) forms large, highly ordered domains when adsorbed on a Cu(111) surface under ultrahigh vacuum conditions. A combination of scanning tunneling microscopy (STM), high resolution electron energy loss spectroscopy (HREELS) and density functional theory (DFT) calculations reveals that the overlayer consists of vertical benzannulated NHC moieties coordinating to Cu adatoms. Long range order results from the placement of the two benzyl units from a single NHC on opposite sides of the benzimidazole moiety, with the planes of their aromatic rings approximately parallel to the surface. The organization of three surface-bound benzyl substituents from three different NHCs into a triangular array controls the formation of a highly ordered Kagome-like lattice on the surface. This study illustrates the importance of dispersive interactions to control the binding geometry and self-assembly of the NHC.

scholarly journals Lithium incorporation into a silica thin film: Scanning tunneling microscopy and density functional theory

2009 ◽  
Vol 80 (24) ◽  
Author(s):  
Jan Frederik Jerratsch ◽  
Niklas Nilius ◽  
Hans-Joachim Freund ◽  
Umberto Martinez ◽  
Livia Giordano ◽  
...  
Keyword(s):  
Thin Film ◽  
Density Functional Theory ◽  
Scanning Tunneling Microscopy ◽  
Density Functional ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Functional Theory ◽  
Silica Thin Film ◽  
Lithium Incorporation

scholarly journals Exact location of dopants below the Si(001):H surface from scanning tunneling microscopy and density functional theory

2017 ◽  
Vol 95 (7) ◽  
Author(s):  
Veronika Brázdová ◽  
David R. Bowler ◽  
Kitiphat Sinthiptharakoon ◽  
Philipp Studer ◽  
Adam Rahnejat ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Scanning Tunneling Microscopy ◽  
Density Functional ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Functional Theory ◽  
Exact Location

Subsurface cation vacancy stabilization of the magnetite (001) surface

Science ◽  
2014 ◽  
Vol 346 (6214) ◽  
pp. 1215-1218 ◽  
Author(s):  
R. Bliem ◽  
E. McDermott ◽  
P. Ferstl ◽  
M. Setvin ◽  
O. Gamba ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Material Interface ◽  
Functional Theory ◽  
Ordered Array ◽  
Low Energy Electron

Iron oxides play an increasingly prominent role in heterogeneous catalysis, hydrogen production, spintronics, and drug delivery. The surface or material interface can be performance-limiting in these applications, so it is vital to determine accurate atomic-scale structures for iron oxides and understand why they form. Using a combination of quantitative low-energy electron diffraction, scanning tunneling microscopy, and density functional theory calculations, we show that an ordered array of subsurface iron vacancies and interstitials underlies the well-known (2×2)R45° reconstruction of Fe3O4(001). This hitherto unobserved stabilization mechanism occurs because the iron oxides prefer to redistribute cations in the lattice in response to oxidizing or reducing environments. Many other metal oxides also achieve stoichiometry variation in this way, so such surface structures are likely commonplace.

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