Differences in the Self-Assembly of Thiol and Disulfide Derivatives of Viologens on Au.
Technical rept. Jun 93-May 94,
WYOMING UNIV LARAMIE DEPT OF CHEMISTRY
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A direct comparison of the self-assembly on Au of thiol and disulfide derivatives of viologens bearing long n-alkyl chains was made in order to ascertain the relative efficiency of monolayer formation for each type of functionality. The structures the two derivatives which were studied can be written as CH3V2CH212SH and CH3V2CH2l2S2 for the thiol and disulfide, respectively, where V2 represents the viologen i.e. N,N-dialkylated-4,4-bipyridinium redox group. In contrast to the behavior of n-alkyl thiols and di-n-alkyl disulfides, which adsorb to give very nearly the same surface coverage and interfacial properties, these two viologen derivatives exhibit markedly different saturation surface coverages for the fully formed monolayers of 1.8 x 10exp -10 mol sq cm for the disulfide and 3.1 x 10exp -10 molsq cm for the thiol, as determined from the charge for exhaustive reduction and reoxidation of the viologen redox groups. jg p.3
- Inorganic Chemistry
- Organic Chemistry
- Physical Chemistry