Sulfur-anchored SAMs

Octanethiol SAMs on Au(lll) have been found to undergo an adlattice transition from a c(4 x 2) to a (6 X 3) structure after long-term storage. HREELS was one of the techniques employed to examine the cause for the transitions. ft was established that the structural transitions were cansed by the dynamic surface diffusion of the sulfur anchor gronp between mnltiple adsorption sites. The adsorption-site exchange also resnlted in orientational changes in alkyl chains. ... 

The highest interfacial electron transfer rate constant yet reported (about 14,000 s ) is for a c-type cytochrome from Aquifex aolicus This protein has a 62-amino acid linker domain by which it is usually anchored to the periplasmic side of the inner membrane this linker has a cysteine as the terminal residue before the signal region, and the sulfur atom provides an anchor point. The cytochrome adsorbs strongly onto a Au electrode that is already modified with a hexane-thiol SAM (note this requires that the molecules in the SAM move or vacate to allow this). The results are striking. 

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