Accession Number : ADA301978

Title :   Differences in the Self-Assembly of Thiol and Disulfide Derivatives of Viologens on Au.

Descriptive Note : Technical rept. Jun 93-May 94,

Corporate Author : WYOMING UNIV LARAMIE DEPT OF CHEMISTRY

Personal Author(s) : Schneider, Thomas ; Buttry, Daniel A.

PDF Url : ADA301978

Report Date : 08 MAR 1994

Pagination or Media Count : 21

Abstract : 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 CH3V(2+)(CH2)12SH and CH3V(2+)(CH2)l2S2 for the thiol and disulfide, respectively, where V(2+) 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 10(exp -10) mol/ sq cm for the disulfide and 3.1 x 10(exp -10) mol/sq cm for the thiol, as determined from the charge for exhaustive reduction and reoxidation of the viologen redox groups. jg p.3

Descriptors :   *GOLD, *SULFIDES, *THIOLS, INTERFACES, LAYERS, COMPARISON, EFFICIENCY, SATURATION, SURFACES, SULFUR, OXIDATION REDUCTION REACTIONS, ALKYL RADICALS, CHEMICAL DERIVATIVES.

Subject Categories : Inorganic Chemistry
      Organic Chemistry
      Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE