Evidence for Cleavage of Disulfides in the Self-Assembled Monolayer on Au(111)

Abstract

Following the proposal of a new structural model by Fenter et al. (Science 1994, 266, 1216, several reports have indicated the existence of dimers in a self-assembled monolayer (SAM) film on Au (111). We synthesized an asymmetric disulfide with hydrocarbon and fluorocarbon chains, and observed phaseseparated domains in the SAM film with force microscopy after annealing at 100 °C for 8 h. The phase separation clearly shows the cleavage of the S-S bond of the disulfide in the film. Although it cannot be confirmed whether the phase-separated domains consist of exchanged dimers or monomers (thiolates), we obtained new insights into the stability and diffusion of molecules in SAM films.

Ultrafast Photosynthetic Reduction of Elemental Sulfur by Au Nanoparticle-Loaded TiO2

“…17 X-ray photoelectron spectroscopic studies showed that a part of S 8 molecules undergoes dissociative adsorption on the Au surface. 18 Also, the adsorption energy of sulfur on the Au surface was calculated to be ca. 250 kJ mol -1 by the density functional theoretical (DFT) calculations for an S-Au 10 model cluster.…”

The interface structure of n-alkylthiolate self-assembled monolayers on coinage metal surfaces

“…This interpretation has been the subject of considerable debate, but does not appear currently to be widely accepted, although the notion that there may be some 'pairing' (in some senses implicit in the discussion of the missing diffracted beams above) remains. One particular objection to the specific model originally proposed is that there is strong evidence [50,51,52] that disulphides adsorb by cleavage of the S-S bond to form thiolates, rather than the opposite effect. A later NIXSW investigation of this same system, involving some of the same researchers [53], did favour S-S headgroup pairing, albeit with different local adsorption sites, one S being close to an atop site, with the second (inequivalent) S atom being offset from a hollow site yet higher above the surface, suggesting that this S atoms does not form a S-Au chemisorption bond.…”

Site-directed immobilisation of antibody fragments for detection of C-reactive protein

“…Some molecules seemed to be removed from the surface, indicating that all of the pTHMMAA molecules were not covalently attached onto the surface. pTHMMAA are expected to attach onto the surface through disulfides that are known to undergo S-S bond reductive cleavage and adsorb as thiolate on gold (Noh and Hara, 2000;Ishida et al, 1997). pTHM-MAA molecules not strongly bound to the gold surface via the disulfide bond seems to be removed and might be replaced by BSA.…”