title: Adlayers of alkanedithiols on Au(111): effect of disulfide reducing agent.
abstract: High-resolution photoemission spectroscopy is used to characterize adlayers of ethane-, hexane-, and nonanedithiol molecules grown on Au(111) surfaces by the immersion method. The effect of using a reducing agent during and after the immersion to inhibit or eliminate S-S bonds is investigated. Our results demonstrate that immersion 24 h in millimolar dithiol ethanolic solutions gives rise to the formation of multilayers; this effect is more pronounced in the case of ethanedithiol, the shortest molecule. A post-treatment with a disulfide reducing agent is effective to produce monolayers of standing-up molecules; this effect is again more pronounced in the case of ethanedithiol. Finally, the immersion 24 h in a solution containing dithiol and the reducing agent gives an unexpected result: most molecules remain adsorbed in the lying-down configuration; in this case, the almost complete suppression of the standing-up phase occurs equally with the three types of molecules, which suggests that the formation of S-S bonds must be important for the lifting of the molecules.
authors.affiliation: Departamento de Fisico Química, Instituto de Fisicoquímica de Córdoba (INFIQC), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
authors.forename: F P
authors.initials: FP
authors.lastname: Cometto
authors.forename: G
authors.initials: G
authors.lastname: Ruano
authors.forename: H
authors.initials: H
authors.lastname: Ascolani
authors.forename: G
authors.initials: G
authors.lastname: Zampieri
mesh_terms: D000473:Alkanes / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D019163:Reducing Agents / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D000473:Alkanes; D004220:Disulfides; D019163:Reducing Agents; D013438:Sulfhydryl Compounds; D006046:Gold