Ethynylbenzene Monolayers on Gold:  A Metal-Molecule Binding Motif Derived from a Hydrocarbon

McDonagh, Andrew M.; Zareie, Hadi M.; Ford, Michael J.; Barton, Christopher S.; Ginic‐Markovic, Milena; Matisons, Janis G.

doi:10.1021/ja064297y

Cited by 34 publications

(45 citation statements)

References 37 publications

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“…The 1-alkyne at the distal end of the monolayer was previously shown to form stable contacts with macroscopic gold electrodes3233, hence it is perfectly suited to form an electrical contact with a gold STM tip. Figure 1b shows a 5 × 5 μm 2 atomic force microscopy (AFM) image of a nonadiyne-modified n-type Si(−111).…”

Section: Resultsmentioning

confidence: 99%

Single-molecule electrical contacts on silicon electrodes under ambient conditions

et al. 2017

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The ultimate goal in molecular electronics is to use individual molecules as the active electronic component of a real-world sturdy device. For this concept to become reality, it will require the field of single-molecule electronics to shift towards the semiconducting platform of the current microelectronics industry. Here, we report silicon-based single-molecule contacts that are mechanically and electrically stable under ambient conditions. The single-molecule contacts are prepared on silicon electrodes using the scanning tunnelling microscopy break-junction approach using a top metallic probe. The molecular wires show remarkable current–voltage reproducibility, as compared to an open silicon/nano-gap/metal junction, with current rectification ratios exceeding 4,000 when a low-doped silicon is used. The extension of the single-molecule junction approach to a silicon substrate contributes to the next level of miniaturization of electronic components and it is anticipated it will pave the way to a new class of robust single-molecule circuits.

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Section: Resultsmentioning

confidence: 99%

Single-molecule electrical contacts on silicon electrodes under ambient conditions

et al. 2017

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“…22,31 Characterization of SAMs of C≡CPh n on gold indicates that the acetylene group binds in an upright configuration on gold. [32][33][34] A recent report from Zaba and coworkers demonstrates that it is possible to form highly-ordered SAMs of n-alkyl acetylenes on gold in non-oxidizing environments; 35 Table S7) than saturated n-alkanes where the HOMO-LUMO gap is much larger (~7 eV). 21 Moreover, the energy level of the HOMO of conjugated molecules aligns more favorably with the Fermi level of the metal, than does that for aliphatic molecules, and results in lower tunneling barriers.…”

Section: Introductionmentioning

confidence: 99%

Tunneling across SAMs Containing Oligophenyl Groups

et al. 2016

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This paper describes rates of charge tunneling across self-assembled monolayers (SAMs) of compounds containing oligophenyl groups, supported on gold and silver, using Ga 2 O 3 /EGaIn as the top electrode. It compares the injection current, J 0 , and the attenuation constant, β, of the simplified Simmons equation, across oligophenyl groups (R = Ph n ; n = 1, 2, 3), with three different anchoring groups (thiol, HSR; methanethiol, HSCH 2 R; and acetylene, HC≡CR) that attach R to the template-stripped gold and silver substrates. The results demonstrate that the structure of the molecules between the anchoring group (-S-or -C≡C-) and the oligophenyl moiety significantly influences charge transport. SAMs of SPh n , and C≡CPh n on gold show similar values of β and log|J 0 | (β = 0.28 ± 0.03 Å -1 and log|J 0 | = 2.7 ± 0.1 for Au/SPh n ; β = 0.30 ± 0.02 Å -1 and log|J 0 | = 3.0 ± 0.1 for Au/C≡CPh n ). The introduction of a single intervening methylene (CH 2 ) group, between the anchoring sulfur atom and the aromatic units to generate SAMs of SCH 2 Ph n , increases β to ~0.6 Å -1 on both gold and silver substrates. (For nalkanethiolates on gold the corresponding values are β = 0.76 Å -1 and log|J 0 | = 4.2). As a generalization, based on this and other work, it seems that increasing the height of the tunneling barrier in the region of the interfaces increases β, and may decrease J 0 ; by contrast, it appears that lowering the height of the barrier at these interfaces has little influence on β or J 0 .

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“…These ligands act as viable alternatives to thiolates for forming protective layers on gold, leading to the so-called "organogold" structures due to the bonding of C atoms directly with Au. By using terminal alkynes as the stabilizers [e.g., phenylacetylene (PA-H) or 9-ethynyl-phenanthrene (EPT-H)], Tsukuda and co-workers have synthesized a series of organogold clusters with precisely defined chemical compositions, such as Au 34 (PA) 16 , Au 43 (PA) 22 , Au 54 (PA) 26 , Au 30 (EPT) 13 , and Au 35 (EPT) 18 . These organogold clusters were formed by direct ligation of the alkyne ligands to the preformed polyvinylpyrrolidone (PVP)-stabilized Au clusters.…”

Section: Introductionmentioning

confidence: 99%

Insights into the PhC≡C/Au Interface

Tang

Jiang

2014

J. Phys. Chem. C

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The phenylethynyl group (PhCC) has attracted attention recently as a new way to passivate gold surfaces, but little is known of the interfacial structure and bonding. Here we employ density functional theory to investigate the organogold interfaces between PhCC and the flat Au(111) surface as well as between PhCC and a model gold nanocluster (Au 20 ). Although isolated PhCC prefers the three-coordinate hollow site on the perfect Au(111) surface, formation of the PhCCAu adatom CCPh motif becomes energetically preferred when the Au adatom is present, resembling the RSAuSR motif on Au(111). However, distinct from the thiolate/Au interface, the PhCCAu adatom −CCPh staple motif features π-bonding of the CC bond to the substrate Au atom in addition to the σ-bonding of the terminal carbon to the gold adatom (or the staple gold atom). Geometry optimization and simulated annealing further show that this new type of staple motif is also the preferred bonding mode of the PhCC groups on the Au 20 cluster. The novel PhCCAuCCPh motif with π-bonding to the Au substrate is expected to be a key feature of the PhCC/Au interface for gold clusters, nanoparticles, and surfaces. This insight will help structural elucidation and chemical understanding of both self-assembled monolayers of PhCC groups on gold surfaces and PhCC protected gold nanosystems.

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Ethynylbenzene Monolayers on Gold: A Metal-Molecule Binding Motif Derived from a Hydrocarbon

Cited by 34 publications

References 37 publications

Single-molecule electrical contacts on silicon electrodes under ambient conditions

Single-molecule electrical contacts on silicon electrodes under ambient conditions

Tunneling across SAMs Containing Oligophenyl Groups

Insights into the PhC≡C/Au Interface

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