Fabrication of Self-Assembled Monolayers Exhibiting a Thiol-Terminated Surface

Abstract

We compare two different strategies for fabricating self-assembled monolayers (SAMs) exhibiting a thiol-terminated organic surface, which recently has attracted considerable interest with regard to the binding of metal, and in particular gold particles, to these organic surfaces. Results obtained by IR spectroscopy and scanning tunneling microscopy (STM) reveal that the straightforward approach, namely, using the corresponding organodithiols, typically leads to the formation of disordered, ill-defined surfaces. We demonstrate that high-quality organothiolate adlayers exhibiting an SH-terminated surface can be prepared using dithiols where one of the thiol groups is protected by a thioester group. After formation of the organothiolate adlayer, the protecting group can be removed by immersion into NaOH solution. IR spectra recorded for the deprotected organothiolate adlayer reveal the presence of a highly oriented organothiolate adlayer.

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

“…[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 reported. 52,53 In order to obtain compact thiol-terminated dithiol SAMs, different formation methods were proposed including protection of one thiol-group as thiolacetate and the following regeneration of SH on top of the formed dithiol SAMs and using organodithiols with more rigid backbonds. 25,52,53 The control of formation condition such as using different solvent, removal of oxygen from SAMs formation solution were also suggested.…”

“…52,53 In order to obtain compact thiol-terminated dithiol SAMs, different formation methods were proposed including protection of one thiol-group as thiolacetate and the following regeneration of SH on top of the formed dithiol SAMs and using organodithiols with more rigid backbonds. 25,52,53 The control of formation condition such as using different solvent, removal of oxygen from SAMs formation solution were also suggested. [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.…”

Amperometric Biosensor for Hydrogen Peroxide Based on Direct Electrocatalysis by Hemoglobin Immobilized on Gold Nanoparticles/ 1,6-Diaminohexane Modified Glassy Carbon Electrode

“…2 Usually, the self-assembling process occurs between thiol-or aminecontaining compounds and gold substrates. 2,9 Recently, the modification of highly ordered mono-or multi-layers on a carbon materials surface has been paid great attention due to the potential of such materials as replacements for precious metal electrodes. 10 One of these modifying methods is the covalent grafting of an amine-containing compound on a glassy carbon surface via electrooxidation.…”

Synthesis and Characterization of Anthracene-2,6-dithioacetate: a Rigid, Conjugated Molecule for the Formation of Monolayers on Gold

“…Furthermore, the formation of SAMs from dithiols can be problematic due to the possibility of double attachment of the molecules. This may be addressed by protecting the thiol groups [10][11][12] or by the use of rigid molecules [8,13]. Interestingly, the new compound anthracene-2,6-dithioacetate unifies both of these concepts.…”