Electrochemically Driven Assembly of Mixed Dithiol Bilayers via Sulfur Dimers

Rifai, S.; Lopinski, Gregory P.; Ward, T. R.; Wayner, Danial D. M.; Morin, Mario

doi:10.1021/la034959m

Cited by 21 publications

(29 citation statements)

References 27 publications

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“…Dithiol SAMs have been utilized to make nanodevices, for measurements of electricity transport, and for multilayer formation. [4][5][6][7][14][15][16][17]22,23,25,[30][31][32][33][34][35][36][37][38][39][40] So far, most studies have focused on their use either as a linker for metal nanoparticles to study charge transfer or as a spacer for multilayer formation. Compared to the well-studied monothiolate SAMs, not many reports have focused on the growth and structure of dithiol SAMs, and disagreements exist among the literature reported concerning the preparation of dithiol SAMs, the resulting structures, and the quality of dithiol SAMs.…”

Section: Introductionmentioning

confidence: 99%

1,6-Hexanedithiol Self-Assembled Monolayers on Au(111) Investigated by Electrochemical, Spectroscopic, and Molecular Mechanics Methods

Qu¹,

Kim²,

Lee³

et al. 2009

J. Phys. Chem. C

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1,6-Hexanedithiol (HSC 6 SH) self-assembled monolayers (SAMs) on Au(111) were formed in a 1 mM ethanolic solution and were investigated by voltammetry in 0.1 M aqueous KOH solution. HSC 6 SH SAMs on Au(111) were further probed by X-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM), sum frequency generation spectroscopy (SFG), and molecular mechanics calculation (MMC). An identical investigation was performed with the self-assembly of hexanethiol (C 6 SH) on Au(111) for comparison. Linear sweep voltammograms showed that a full monolayer of thiolate (7.6 ((0.2) × 10 -10 mol -2) chemisorbed on Au(111) with both HSC 6 SH and C 6 SH, while the peak potential of the electroreduction of the former assembly was more negative than that of the latter. XPS revealed that two different forms of sulfur existed at HSC 6 SH SAMs on Au(111), i.e. a thiolate and a thiol. The STM image could not be resolved with HSC 6 SH SAMs, while it was atomically well-defined with the C 6 SH case. SFG results showed that alkyl chains within the HSC 6 SH SAMs were in an all-trans conformation. Thus the experimental results concluded that densely packed and higly oriented HSC 6 SH SAMs could be successfully formed on Au(111) with the incubation conditions in the practical solution. MMC presented that HSC 6 SH SAMs were more stable than C 6 SH ones because of the additional end-end interaction among the thiol groups faced up to the air, albeit both SAMs were tilted by 28°from the surface normal.

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Section: Introductionmentioning

confidence: 99%

1,6-Hexanedithiol Self-Assembled Monolayers on Au(111) Investigated by Electrochemical, Spectroscopic, and Molecular Mechanics Methods

Qu¹,

Kim²,

Lee³

et al. 2009

J. Phys. Chem. C

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“…[3][4][5][6][7][14][15][16][17][22][23][24][25] It can also be used as building blocks for constructing multilayers. [27][28][29][30][31][32][33][34][35] The most suitable constituent for the formation of thiol terminated SAMs is dithiol. Dithiol SAMs have been utilized to make nanodevices, measurements of electricity transport and multilayer formation.…”

Section: Introductionmentioning

confidence: 99%

“…[22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]41,[45][46][47][48][49][50][51][52][53][54][55] In this upright molecular structure, the unbound thiol group is pendent with respect to the Au substrate and serves as the platform for the applications, such as the preparation of copper (I)-dithiol or CdS nanoparticle-dithiol multilayer thin films, the formation of multilayer through disulfide linkage spontaneously or electrochemically, the measurement of electron transfer through single molecule or the construction of metalmolecule-metal sandwich structure. 3,[22][23][24][25][26][27][30][31][32][33][34][35][36][37][38] However, the quality of those thiol terminated surface has been debated. Loose pack, ill-defined dithiol adlayers, which were prepared by simple immersion of gold substrate into a solution of dithiol, were rep...…”

Section: Introductionmentioning

confidence: 99%

“…[22][23][24][25]30,31,41,[47][48][49][50][51][54][55][56][57] Formation of disulfide bond through the terminated free thiols on top of dithiol SAMs were reported as well. [32][33][34][35]48,49 Those interlayer and intralayer disulfide linkage will result in the formation of multilayer and rearrangement of molecular configuration of dithiol molecules in the SAM, respectively. In this study, a series of densely packed, looping structure free, thiol-terminated alkanedithiol SAMs with higher stability than those of monothiolate SAMs were prepared.…”

Section: Introductionmentioning

confidence: 99%

“…46 Other multilayers were not noticed with the experimental conditions of the dithiols investigated in this study, reflecting that formation of SAMs and multilayers is the sensitive function of the experimental variables of medium, concentration, impurities and immersion time among others. [27][28][29][30][31][32][33][34][35] To clearly see the relationship between the reductive desorption peak potentials in different alkyl chain-length thiol and dithiol, the reductive peak potential and the peak potential difference between thiol and dithiol were plotted as a function of the number of carbons in those molecules and are shown in Figure 3 and 4, respectively. Figure 3 shows that, the reductive peak potentials of dithiol SAMs were always more negative than those of the corresponding thiol SAMs, which indicates that the dithiol SAMs are more stable than the corresponding monothiol SAMs.…”

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confidence: 99%

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1,n-Alkanedithiol (n = 2, 4, 6, 8, 10) Self-Assembled Monolayers on Au(111): Electrochemical and Theoretical Approach

Qu¹,

Kim²,

Lee³

et al. 2009

Bulletin of the Korean Chemical Society

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The structures of 1,n-alkanedithiol (n = 2, 4, 6, 8, 10) self-assembled monolayers (SAMs) on a Au(111) substrate were investigated by electrochemical measurements and theoretical calculations. The results of the experimental techniques indicated that the dithiols, except n = 2, showed an upright molecular structure in the SAMs, in which alkanedithiols were bound to the Au surface via only one thiol functionality and the other one faced up to the air. The results also suggested that the formed dithiol SAMs were densely packed and highly oriented. Except ethanedithiol, which was thought to form a bilayer, the reductive desorption peak potentials of 1,n-alkanedithiol (n = 4, 6, 8, 10) SAMs were more negative than those of the corresponding monothiol ones in 0.1 M KOH solutions. This illustrates that the dithiol SAMs had higher stability than the corresponding monothiol ones. The major part of the high stability may be attributed to the van der Waals interaction among the sulfur atoms on top of the dithiol SAMs. The molecular modeling calculation showed that the structures of dithiol SAMs were similar to those of the corresponding monothiol SAMs and that all the dithiol SAMs, except ethanedithiol, were more stable than the corresponding monothiol SAMs. The calculated energy differences between dithiol and monothiol SAMs decreased with the increment of alkyl-chain length.

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Cyclic Control of the Surface Properties of a Monolayer‐Functionalized Electrode by the Electrochemical Generation of Hg Nanoclusters

Riskin

Basnar

Katz

et al. 2006

Chemistry A European J

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Hg(2+) ions are bound to a 1,4-benzenedimethanethiol (BDMT) monolayer assembled on a Au electrode. Electrochemical reduction of the Hg(2+)-BDMT monolayer to Hg(+)-BDMT (at E degrees =0.48 V) and subsequently to Hg(0)-BDMT (at E degrees =0.2 V) proceeds with electron-transfer rate constants of 8 and 11 s(-1), respectively. The Hg(0) atoms cluster into aggregates that exhibit dimensions of 30 nm to 2 microm, within a time interval of minutes. Electrochemical oxidation of the nanoclusters to Hg(+) and further oxidation to Hg(2+) ions proceeds with electron-transfer rate constants corresponding to 9 and 43 s(-1), respectively, and the redistribution of Hg(2+) on the thiolated monolayer occurs within approximately 15 s. The reduction of the Hg(2+) ions to the Hg(0) nanoclusters and their reverse electrochemical oxidation proceed without the dissolution of mercury species to the electrolyte, implying high affinities of Hg(2+), Hg(+), and Hg(0) to the thiolated monolayer. The electrochemical transformation of the Hg(2+)-thiolated monolayer to the Hg(0)-nanocluster-functionalized monolayer is characterized by electrochemical means, surface plasmon resonance (SPR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact-angle measurements. The Hg(0)-nanocluster-modified surface reveals enhanced hydrophobicity (contact angle 76 degrees ) as compared to the Hg(2+)-thiolated monolayer (contact angle 57 degrees ). The hydrophobic properties of the Hg(0)-nanocluster-modified electrode are further supported by force measurements employing a hydrophobically modified AFM tip.

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Electrochemically Driven Assembly of Mixed Dithiol Bilayers via Sulfur Dimers

Cited by 21 publications

References 27 publications

1,6-Hexanedithiol Self-Assembled Monolayers on Au(111) Investigated by Electrochemical, Spectroscopic, and Molecular Mechanics Methods

1,6-Hexanedithiol Self-Assembled Monolayers on Au(111) Investigated by Electrochemical, Spectroscopic, and Molecular Mechanics Methods

1,n-Alkanedithiol (n = 2, 4, 6, 8, 10) Self-Assembled Monolayers on Au(111): Electrochemical and Theoretical Approach

Cyclic Control of the Surface Properties of a Monolayer‐Functionalized Electrode by the Electrochemical Generation of Hg Nanoclusters

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