Disulfides, self-assembled monolayers

Cooke and coworkers have reported preparation of flavin-modified electrodes using a similar electropolymerization procedure.34 They have also studied electrodes coated with self-assembled monolayers (SAMs) formed from both flavin39 and phenanthrenequinone disulfides.59 The monolayers are stable in CH2C12 solution, and, as with the electrodes formed from 30, show redox-dependent binding behavior similar to that seen in solution. Interestingly, the phenanthrenequinone SAM... 

Imahori et al. reported on the energy transfer in mixed self-assembled monolayers of pyrene and porphyrin [83]. The molecular structures of the disulfide-terminated chromophores are illustrated in Figure 5.53. Porphyrin and pyrene dimers were coadsorbed onto Au(lll) mica substrates in different ratios. The ratios of pyrene to porphyrin were experimentally determined from absorption spectroscopy and the pyrene dimer was observed to adsorb preferentially, possibly due to its strong... 

Beer and co-workers have investigated this concept using self-assembled monolayers of the l,l -bis(alkyl-M-amido)ferrocene 55 on gold electrodes [41]. The pendant disulfide groups serve to covalently anchor the receptor to the gold surface. In electrochemical experiments on 55 in acetoni-trile/dichloromethane solution anion-induced cathodic shifts of the fer-rocene/ferrocenium redox couple were observed for chloride (40 mV),... 

Self-assembled monolayers (SAMs) provide a simple way to functionalize coinage metal electrode surfaces by organic molecules containing anchor groups such as thiols, disulfides, or silanes. The monolayers are usually well packed, ordered, and stable and can be easily tailored for certain applications by changing the functional terminal group in contact with the solution. Alkanethiol monolayers can... 

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