SAMs on Gold Derived from the Direct Adsorption of Alkanethioacetates Are Inferior to Those Derived from the Direct Adsorption of Alkanethiols

Béthencourt, Mathilde I.; Srisombat, Laongnuan; Chinwangso, Pawilai; Lee, T. Randall

doi:10.1021/la803179q

Cited by 76 publications

(101 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our computed dissociation transitions state and energetic are in good agreement with earlier experimental observations [88,91,92]. Our calculations seem therefore to suggest a homolytic cleavage assisted by a polarized transition state.…”

Section: Thioacetatessupporting

confidence: 90%

“…Moreover, it has been shown that experimentally the thioacetates undergo spontaneous deprotection upon adsorption, leading to radical thiols to be adsorbed on the surface [91,92]. This approach has been successively used for the synthesis of SAMs of different nature [92].…”

Section: Thioacetatesmentioning

confidence: 99%

“…In fact, among the presented cases above, the S-X bond cleavage is still controversial in some cases (X = Me) [74][75][76][77] while it has been unequivocally proved to be cleaved in others (X = SCH 3 , COCH 3 and CN) [78][79][80][81][82][83][84][85][86][87][88][89][90][91][92]. In the case of dialkylsulfides (CH 3 SCH 3 ), a combined spectroscopic data suggest that there is no cleavage of S-C bond and sulfur interacts with the metal surface through a dative bond during the formation of SAM [74][75][76][77].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

On the kinetics and thermodynamics of S–X (X = H, CH3, SCH3, COCH3, and CN) cleavage in the formation of self-assembled monolayers of alkylthiols on Au(111)

Jaccob¹,

Rajaraman²,

Totti³

2012

Theor Chem Acc

View full text Add to dashboard Cite

Abounding potential technological applications is one of the many reasons why adsorption of aliphatic thiols on gold surface is a subject of intense research by many research groups. Understanding and exploring the nature of adsorbed species, the site of adsorption and the nature of interaction between adsorbed species and the gold surface using experimental and theoretical investigations is an active area of pursuit. However, despite a large number of investigations to understand the atomistic structures of thiols on Au(111), some of the basic issues are still unaddressed. For instance, there is still no clear information about the mechanism of adsorption of alkylthiol on gold surface. Furthermore, the reactivity and mechanism of adsorption of alkylthiol is likely to differ when gold adatoms and/or vacancies in the gold layers are considered. In this work, we have tackled these issues by computing the stationary states involved in the thiols adsorption in order to shed light on the kinetics aspects of adsorption process. In this respect, we have considered a variety of thiols into consideration such as methylthiol, dimethylsulfide, dimethyldisulfide, thioacetates, and thiocyanates. We have also considered the cleavage mechanism in the clean and the reconstructed surface scenario and the structure, energetics and spin densities have been computed using electronic structure calculations. For all the studied cases, an homolytic cleavage of CH 3 S-X (X = H, CH 3 , SCH 3 , CN, and COCH 3 ) bond has been found to occur upon adsorption on the gold surface.

show abstract

Section: Thioacetatessupporting

confidence: 90%

Section: Thioacetatesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

On the kinetics and thermodynamics of S–X (X = H, CH3, SCH3, COCH3, and CN) cleavage in the formation of self-assembled monolayers of alkylthiols on Au(111)

Jaccob¹,

Rajaraman²,

Totti³

2012

Theor Chem Acc

View full text Add to dashboard Cite

show abstract

“…1(e)] hence, an imperfect molecular self-assembly will still work¯ne and will provide a functional TJMD. 35 In a TJMD, molecular channels are chemically anchored between the two metal electrodes [ Fig. 1(e)].…”

Section: Molecules Serve As a Device Element Not As A Physical Barriermentioning

confidence: 99%

Advantages of Prefabricated Tunnel Junction-Based Molecular Spintronics Devices

Tyagi

Friebe

Baker

2015

NANO

View full text Add to dashboard Cite

Molecule-based devices may govern the advancement of the next generation's logic and memory devices. Molecules have the potential to be unmatched device elements as chemists can mass produce an endless variety of molecules with novel optical, magnetic and charge transport characteristics. However, the biggest challenge is to connect two metal leads to a target molecule (s) and develop a robust and versatile device fabrication technology that can be adopted for commercial scale mass production. This paper discusses distinct advantages of utilizing commercially successful tunnel junctions as a vehicle for developing molecular spintronics devices. We describe the use of a prefabricated tunnel junction with the exposed sides as a testbed for molecular device fabrication. On the exposed sides of a tunnel junction molecules are bridged across an insulator by chemically bonding with the two metal electrodes; sequential growth of metal-insulator-metal layers ensures that separation between two metal electrodes is controlled by the insulator thickness to the molecular device length scale. This paper highlights various attributes of tunnel junction-based molecular devices with ferromagnetic electrodes for making molecular spintronics devices. We strongly emphasize a need for close collaboration between chemists and magnetic tunnel junction (MTJ) researchers. Such partnerships will have a strong potential to develop tunnel junction-based molecular devices for futuristic areas such as memory devices, magnetic metamaterials, high sensitivity multi-chemical biosensors, etc.

show abstract

“…8,9,[13][14][15] It has been observed that the direct adsorption of alkanethioacetates (ATAs) on gold in solution generates loosely packed and disordered SAMs compared to the corresponding alkanethiols (ATs). 8,13,15 A kinetics study showed that the adsorption rate is slower for ATAs in pure solvents than for ATs. 14 Fully covered monolayers from aromatic thioacetates were formed after a longer immersion period of several days or in a concentrated 30 mM solution.…”

mentioning

confidence: 99%

Direct Adsorption and Molecular Self-Assembly of Octylthioacetates on Au(111) in the Vapor Phase

Park¹,

Kang²,

Kim³

et al. 2011

Bulletin of the Korean Chemical Society

View full text Add to dashboard Cite

Self-assembled monolayers (SAMs) are a very promising construct for monomolecular thin films with various practical applications because they are very amenable to surface modification and functionalization of metal surfaces.1-6 Alkanethiol SAMs on gold surfaces have been thoroughly studied by a number of research groups, and their structural properties have been well characterized. Organic thiols are prone to easily oxidize to disulfides or other oxidized species that can affect the formation and structure of SAMs. 7,8 The presence of disulfides or oxidized compounds in thiol samples often yields poorly ordered SAMs containing a high defect density and disordered phases. An approach that minimizes undesirable thiol oxidation is the use of a protected thiol that is deprotected in situ before or during SAM formation. The protection of thiol groups can be readily accomplished by acetylation. SAMs derived from acetyl protected thiols (thioacetates) on gold have usually been formed via an in situ deprotection process of the acetyl group in strong acidic or basic solutions.9-11 Other deprotection techniques have also been developed that use organic compounds such as triethylamine, 12 tetrabutylammonium cyanide, 13 and 1,8-diazabicyclo[5.4.0]undec-7-ene, 8 and organic SAMs with a high degree of structural order have been successfully constructed in solutions containing these deprotection reagents.In contrast, there have been only limited reports of investigations into the direct adsorption of thioacetyl-protected organic molecules on gold in solution without any deprotection reagents. 8,9,[13][14][15] It has been observed that the direct adsorption of alkanethioacetates (ATAs) on gold in solution generates loosely packed and disordered SAMs compared to the corresponding alkanethiols (ATs). 8,13,15 A kinetics study showed that the adsorption rate is slower for ATAs in pure solvents than for ATs. 14 Fully covered monolayers from aromatic thioacetates were formed after a longer immersion period of several days or in a concentrated 30 mM solution.9 In general, organic thiol SAMs can be formed by both solution and vapor phase deposition, and both deposition methods yield identical SAM structures containing the hexagonal (√3 × √3)R30 o or c(4 × 2) structure at saturation coverage. 1,3,16 To the best of our knowledge, however, there have been no reports describing organic thioacetate SAMs on gold grown by vapor deposition.In this study, to understand the formation of thioacetate SAMs on gold depending on deposition method, we directly compared the surface structures of the acetyl-protected octylthioacetate (OTA, CH 3 (CH 2 ) 7 SCOCH 3 ), SAMs on Au (111) The STM images in Figure 1 clearly show considerable structural differences between OTA SAMs on Au(111) grown from solution and vapor deposition at 50 o C for 24 h. OTA SAMs grown from solution were mainly composed of disordered phases containing many vacancy islands (VIs, dark holes), as shown in Figure 1a. The surface structures of these OTA SAMs were nearly identical to ...

show abstract

SAMs on Gold Derived from the Direct Adsorption of Alkanethioacetates Are Inferior to Those Derived from the Direct Adsorption of Alkanethiols

Cited by 76 publications

References 67 publications

On the kinetics and thermodynamics of S–X (X = H, CH3, SCH3, COCH3, and CN) cleavage in the formation of self-assembled monolayers of alkylthiols on Au(111)

On the kinetics and thermodynamics of S–X (X = H, CH3, SCH3, COCH3, and CN) cleavage in the formation of self-assembled monolayers of alkylthiols on Au(111)

Advantages of Prefabricated Tunnel Junction-Based Molecular Spintronics Devices

Direct Adsorption and Molecular Self-Assembly of Octylthioacetates on Au(111) in the Vapor Phase

Contact Info

Product

Resources

About