TY  - JOUR
AU  - Li, Z.
AU  - Han, B.
AU  - Wan, L. J.
AU  - Wandlowski, Th.
TI  - Supramolecular Nanostructures of 1,3,5-Benzene-tricarboxylic Acid at Electrified Au(111)/0.05 M H2SO4 Interfaces - An in-situ Scanning Tunneling Microscopy Study
JO  - Langmuir
VL  - 21
SN  - 0743-7463
CY  - Washington, DC
PB  - ACS Publ.
M1  - PreJuSER-46889
SP  - 6915 - 6928
PY  - 2005
N1  - Record converted from VDB: 12.11.2012
AB  - The potential-induced adsorption and self-assembly of 1,3,5-benzene-tricarboxylic acid (TMA) was investigated at the electrified Au(111)/0.05 M H2SO4 interface by in-situ scanning tunneling microscopy (STM) and surface enhanced infrared reflection absorption spectroscopy (SEIRAS) in combination with electrochemical techniques. Depending on the applied electric field, TMA forms five distinctly different, highly ordered supramolecular adlayers on Au(111) surfaces. We have elucidated their real-space structures at the molecular scale. In the potential range -0.25 V < E < 0.20 V, planar-oriented TMA molecules form a hexagonal open-ring honeycomb structure, Ia, a hydrogen-bonded ribbon-type phase, Ib, and a herringbone-type phase, Ic, stabilized by directional hydrogen bonding and weak substrate-adsorbate interactions. Interfacial water molecules are being replaced. In 0.20 V < or = E < 0.40 V, e.g., around the potential of zero charge, and at slightly higher coverages, a close-packed physisorbed adlayer of hydrogen-bonded TMA dimers, II, was observed. Further increase of the electrode potential to positive charge densities causes an orientation change from planar to upright. An initially disordered phase, IIIa, transforms into an ordered, stripelike chemisorbed adlayer, IIIb, of perpendicularly oriented TMA molecules. One carboxylate group per molecule is bound to the electrode surface, while the two other protonated carboxyl groups are directed toward the electrolyte and act as structure-determining components of a hydrogen-bonded two-dimensional ladder-type network. Structural transitions between the various types of ordered molecular adlayers are attributed to (hole) nucleation and growth processes.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:16008404
UR  - <Go to ISI:>//WOS:000230507400037
DO  - DOI:10.1021/la0507737
UR  - https://juser.fz-juelich.de/record/46889
ER  -