Loss of Hydrogen upon Exposure of Thiol to Gold Clusters at Low Temperature

Abstract

Gold-acetone-dodecanethiol and gold-acetone-phenylethanethiol colloids were prepared by the solvated metal atom dispersion method. Hydrogen evolution occurred at fairly low temperature, when the melting acetone-gold solvate encountered the thiol molecules, due to S-H bond scission. The gas inside the reactor was analyzed by gas chromatography, and the moles of H(2) was determined by calibration curves obtained from a series of known concentration samples. The gold-to-thiolate ratio was calculated using thermal gravimetric analysis. The average particle diameter was also calculated using the gold-to-thiolate ratio.

Quantifying thiol–gold interactions towards the efficient strength control

“…The dissociated hydrogen atoms could either adsorb on gold surfaces or release from the surface in the form of H 2 . Ensemble experiments also indicated that the loss of hydrogen could undergo a very slow process 56,58 , even as long as several minutes, which is longer than the interaction time (3.0 s) between isolated thiols and gold surfaces in our SMFS experiments for isolated thiols. The released H located on the gold surface could lead to drastic changes in rupture forces 45,52 .…”

“…As discussed above, the coordinate bond could actually form between the -SH group and gold surface in the initial stage, followed by the dissociation of S-H bond that results in a thiyl radical, which would finally form a gold-thiolate covalent bond at the gold-sulfur interface [45][46][47][48][49][50][51][54][55][56][57][58] . These findings indicate that the formation of Au-S covalent bonds needs a certain time to complete.…”

Gold nanoparticles obtained by aqueous digestive ripening: Their application as X-ray contrast agents

“…Acetone was used as preliminary stabilizing solvent for the preparation of highly concentrated Au SMA (>4 mg Au/mL) [21][22][23]. The further addition of a portion of Au/acetone SMA to a water solution of an excess of CH 3 O-PEG 5000 -SH ligand allowed to obtain a deep purple solution of Au aggregates stabilized by the strong soft-soft interaction between the sulfur atom of the ligand and Au atoms on the nanoparticle surface [31]. These aggregates appeared predominantly comprised of highly defective particles, well separated from each other with a broad particle size distribution (2.5-21.5 nm) and a mean particle diameter of 7.5 nm (Fig.…”

Nanohybrids of Gold Particles

“…Unsuccessful experiments were carried out, where a large excess of different ligands was added to ci Au ν oda -4 under various conditions. In light of the fact that thiols first associate weakly to gold while retaining their proton and form the strong thiolate bond only after the proton is lost in the second step, [29,30] it was also attempted to aid the process by carrying out the functionalization reactions with thiols in the presence of the oxidizing agent 2,3-dichloro-5,6-dicyano-1,4-benzoquinone or, as an alternative, the Dess-Martin periodinane. [31] This was not successful either, nor was the tentative employment of disulfide S 2 λ-10 , which does not need to be oxidized (see Section 5.3).…”