Adsorption of 1,3-benzenedithiol and 1,3-benzenedimethanethiol on gold surfaces.
The adsorption characteristics of 1,3-benzenedithiol (1,3-BDT) and 1,3-benzenedimethanethiol (1,3-BDMT) on Au surfaces are investigated by means of surface-enhanced Raman scattering, UV/Vis absorption spectroscopy, and cyclic voltammetry (CV). 1,3-BDMT is found to adsorb via two S-Au linkages at concentrations below monolayer coverage, but to have an upright geometry as the concentration increases on Au nanoparticles. On the other hand, 1,3-BDT is found to adsorb by forming two S-Au linkages, regardless of concentration, based on the disappearance of the nu(SH)(free) stretching band. Because of the absence of the methylene unit, 1,3-BDT appears not to self-assemble efficiently on Au surfaces. The UV/Vis absorption spectroscopy and CV techniques are also applied to check the formation of self-assembled monolayers of 1,3-BDT and 1,3-BDMT on Au. Density functional theory calculations based on a simple adsorption model using an Au(8) cluster are performed to better understand the nature of the adsorption characteristics of 1,3-BDT and 1,3-BDMT on Au surfaces.
Lim
Jong Kuk
JK
Department of Chemistry, Soongsil University, Seoul 156-743, Korea.
Kim
Youngmin
Y
Kwon
Ohyun
O
Joo
Sang-Woo
SW
D000327:Adsorption; D001555:Benzene Derivatives / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013499:Surface Properties
C516314:1,4-benzenedithiol; D001555:Benzene Derivatives; D013438:Sulfhydryl Compounds; D006046:Gold; C512626:1,4-benzenedimethanethiol