TY - JOUR
T1 - Spontaneously organized molecular assembly of an aromatic organic disulfide on silver/platinum alloy surfaces
T2 - an angle dependent X-ray photoemission investigation
AU - Bandyopadhyay, K.
AU - Mayya, K. S.
AU - Vijayamohanan, K.
AU - Sastry, Murali
PY - 1997/12
Y1 - 1997/12
N2 - This article reports an angle dependent X-ray photoemission investigation on the formation of a self-assembled monolayer of a small organic disulfide molecule (Naphtho[1,8-cd]-1,2-dithiole) on silver/platinum alloy surfaces. In addition to the S 2p signal normally associated with thiolate bond formation, a high binding energy S 2p signal was observed and is assigned to a sulfonic acid moiety. This is the first such report of sulfonic acid formation in disulfide systems and is quite similar to the process occurring on copper and silver surfaces for n-alkane thiols. The angle dependent intensities of the C 1s, S 2p and Ag 3d core levels were used to make a quantitative estimate of the surface composition and thus obtain information on the molecular orientation. The molecule was oriented almost normal to the silver/platinum alloy surface with the sulfonic acid moiety being closer to the monolayer-air interface than the thiolate sulfur which was very close to the alloy surface. This is explainedas arising due to steric effects associated with the larger sulfonic acid group.
AB - This article reports an angle dependent X-ray photoemission investigation on the formation of a self-assembled monolayer of a small organic disulfide molecule (Naphtho[1,8-cd]-1,2-dithiole) on silver/platinum alloy surfaces. In addition to the S 2p signal normally associated with thiolate bond formation, a high binding energy S 2p signal was observed and is assigned to a sulfonic acid moiety. This is the first such report of sulfonic acid formation in disulfide systems and is quite similar to the process occurring on copper and silver surfaces for n-alkane thiols. The angle dependent intensities of the C 1s, S 2p and Ag 3d core levels were used to make a quantitative estimate of the surface composition and thus obtain information on the molecular orientation. The molecule was oriented almost normal to the silver/platinum alloy surface with the sulfonic acid moiety being closer to the monolayer-air interface than the thiolate sulfur which was very close to the alloy surface. This is explainedas arising due to steric effects associated with the larger sulfonic acid group.
KW - Alloy surfaces
KW - Aromatic organic disulfide
KW - Molecular assembly
KW - X-ray photoemission spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=0012588568&partnerID=8YFLogxK
U2 - 10.1016/s0368-2048(97)00090-x
DO - 10.1016/s0368-2048(97)00090-x
M3 - Article
AN - SCOPUS:0012588568
SN - 0368-2048
VL - 87
SP - 101
EP - 107
JO - Journal of Electron Spectroscopy and Related Phenomena
JF - Journal of Electron Spectroscopy and Related Phenomena
IS - 2
ER -