Partial Electron Transfer in Octadecanethiol Binding to Gold

Krysiński, Paweł; Chamberlain, Richard V.; Majda, Marcin

doi:10.1021/la00023a060

Cited by 46 publications

(46 citation statements)

References 6 publications

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“…This conclusion is supported by the 1:2 Hg:thiol stoichiometry found in bulk Hg thiolates [7], where the strong covalent S-Hg-S bond is found to involve a transfer of one electron per thiol with the corresponding loss of the terminal hydrogen. In contrast, on Au(111), only a partial transfer, 0:3 electrons per thiol, is found [23]. We also note that the equal q k widths of the odd-and even-order GID peaks in Fig.…”

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confidence: 58%

Crystalline Phases of Alkyl-Thiol Monolayers on Liquid Mercury

et al. 2005

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The structure of octadecanethiol monolyers on liquid Hg surfaces, measured with subangstrom resolution, evolves with increasing coverage from a laterally disordered phase of surface-parallel molecules to ordered rotator phases of surface-normal molecules. For the latter, an abrupt transition is found at 19 A(2)/molecule from a rectangular packing of molecules tilted by 27 degrees in the nearest-neighbor direction to a hexagonal unit cell of untilted molecules. The unit cell of the tilted phase is centered for the chains and noncentered for the headgroups. The thiol headgroups associate in pairs with a single Hg atom, and the bonds form long-range orientational order. The different order of thiols on Au(111) and on Hg highlights the subphase's role in determining the overlayer's structure.

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confidence: 58%

Crystalline Phases of Alkyl-Thiol Monolayers on Liquid Mercury

et al. 2005

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“…In potentiometry, the electrode potential is recorded vs. that of a reference electrode, while no net current flows through the external circuit. Similar measurements have been used by a limited number of groups for studying the different stages of alkanethiol chemisorption on various surfaces following thiol injection into the electrolyte solution [41,[90][91][92][93][94]. Majda et al [94] were the first to study the potential changes of an Au surface, while transferring a Langmuir-Blodgett film of alkanethiols.…”

Section: Introductionmentioning

confidence: 94%

“…Similar measurements have been used by a limited number of groups for studying the different stages of alkanethiol chemisorption on various surfaces following thiol injection into the electrolyte solution [41,[90][91][92][93][94]. Majda et al [94] were the first to study the potential changes of an Au surface, while transferring a Langmuir-Blodgett film of alkanethiols. Further work was carried out by Porter [92] Paik [90,93] and Kim [91].…”

Section: Introductionmentioning

confidence: 94%

Characterization of n-alkanethiol self-assembled monolayers on mercury by impedance spectroscopy and potentiometric measurements

Cohen-Atiya

Nelson

Mandler

2006

Journal of Electroanalytical Chemistry

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“…18,19 The redox nature of the chemisorption process has been demonstrated by the considerable (80%) degree of electron transfer from preformed C 18 SH Langmuir monolayers when they are transferred as Langmuir-Blodgett (LB) films to an Au substrate. 20 Ab initio calculations 21 and Kelvin probe measurements 22,23 suggest that the extent of charge transfer in the gold thiolate ranges from 0.4 to 0.7 depending on the geometry of the adsorption site. Stratmann and co-workers 24 have shown that applied potentials slightly positive of the potential of zero charge (pzc) cause the thiol molecule to be "attracted" to the gold surface during SAM formation.…”

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confidence: 99%

Potential-Assisted Deposition of Alkanethiols on Au: Controlled Preparation of Single- and Mixed-Component SAMs

2000

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The commonly used method of preparing RS/Au self-assembled monolayers (SAMs) involves a passive incubation process in a nonabsorbing solvent. Preparation of mixed-component SAMs is particularly problematic under these conditions. The time course of the open circuit potential in the passive adsorption experiment suggests that control of the deposition potential could lead to a faster and ultimately more complete SAM formation process. This is shown to be the case, as both C16 RS/Au SAMs and mixed C16/HOOCC15S/Au SAMs are shown to be readily prepared in approximately 15 min from 5 mM thiol solutions at potentials ranging from 200 to 600 mV (vs Ag/AgCl). The blocking properties of the resulting C16 SAMs are excellent. This technique provides access to mixed-composition SAMs otherwise inaccessible using deposition under open circuit conditions. Although RSH/Au self-assembled monolayers (SAMs) have been the subject of several hundred scientific reports, the mechanism by which they form is relatively poorly understood and characterized. It is also widely acknowledged by practitioners in the field that it is difficult to obtain SAMs with identical function (i.e. electron-transfer blocking capability 1a ) or structure (i.e. determined by diffraction 1b ) although ostensibly identical preparation conditions may have been used. Although it is often stated that SAMs offer a chemist the ability to "engineer" a surface with "tuned" properties, the preparation of both single-component and multicomponent SAMs in a predictable manner is problematic. 2 We are very interested in (i) obtaining high-quality, extensively blocked (to aqueous redox couples) SAMs formed from n-alkanethiols and (ii) obtaining binary and higher order SAMs whose composition is both predictable and reproducible. To this end we have found that the chemisorption of the alkanethiol can be controlled electrochemically. A modest anodic potential applied to the gold electrode during RSH adsorption very quickly leads to high-quality SAMs with excellent performance characteristics. This potential deposition process also allows one to precisely control the ratio of components in a model binary SAM made up of C 16 SH and HSC 15 CO 2 H.Alkanethiol monolayer systems have been most commonly prepared either by incubation of a gold substrate in a thiol-containing solution or by deposition from the gas phase. 2 Full, close-packed coverage is, however, problematic from the gas phase. 2 In neither method is the potential of the gold substrate fixed, and in the solution incubation experiment the complexities arising from a Nernstian redox pinning are not generally acknowledged. Although the self-assembly process is simple, it is often both time-consuming and irreproducible. 1a,b In the solution-based process, the surface coverage increases with increased incubation time 3-5 and fully covered, highly ordered monolayers may require days or even weeks to prepare. 3-6 Furthermore, it is difficult or impossible to prepare binary (or higher order) SAMs with predictable composition ...

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Partial Electron Transfer in Octadecanethiol Binding to Gold

Cited by 46 publications

References 6 publications

Crystalline Phases of Alkyl-Thiol Monolayers on Liquid Mercury

Crystalline Phases of Alkyl-Thiol Monolayers on Liquid Mercury

Characterization of n-alkanethiol self-assembled monolayers on mercury by impedance spectroscopy and potentiometric measurements

Potential-Assisted Deposition of Alkanethiols on Au: Controlled Preparation of Single- and Mixed-Component SAMs

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