Noradrenaline and a thiol analogue on gold surfaces: An infrared reflection-absorption spectroscopy, X-ray photoelectron spectroscopy, and near-edge X-ray absorption fine structure spectroscopy study
2011 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 115, no 1, 165-175 p.Article in journal (Refereed) Published
Self-assembled monolayers and multilayers of a noradrenaline analogue (Nor-Pt) on gold substrates as well as multilayers of noradrenaline have been investigated by means of the molecular orientation, the molecule-surface interaction, the molecular composition and the functional group availability for further biointeraction processes, using X-ray photoelectron spectroscopy (XPS), infrared reflection-absorption spectroscopy (IRAS), and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. A chemical shift (1.7 eV) of the S 2p peak to lower binding energies is observed, in the XPS spectrum, indicating that the Nor-Pt molecules are chemisorbed onto the gold substrate. The IR results show that Nor-Pt adsorbate has the C=O stretching vibration modes parallel oriented relative to the gold substrate. The average tilt angle of the aromatic ring relative to the gold surface normal is determined to be approximately 51°, based on the NEXAFS measurements on Nor-Pt monolayers. The experimental results and assignments are supported with theoretical studies where we use the building block principle in the spectral analysis and compare with the measurements of noradrenaline and Nor-Pt. The theoretical calculations are shown to be useful; for angle dependence NEXAFS studies as resonances with fully φ* or σ* character are preferred for correct analysis.
Place, publisher, year, edition, pages
2011. Vol. 115, no 1, 165-175 p.
Angle dependence, Aromatic rings, Biointeraction, Building blockes, C-O stretching, Gold substrates, Gold surfaces, Infrared reflection absorption spectroscopy, Molecular compositions, Molecule surface, Near-edge X-ray absorption fine structure spectroscopies, Spectral analysis, Theoretical calculations, Theoretical study, Tilt angle, XPS spectra, Absorption, Binding energy, Chemisorption, Electron energy levels, Functional groups, Gold, Gold metallurgy, Molecular orientation, Multilayers, Photoelectricity, Photons, Platinum, Self assembled monolayers, Spectrum analysis, Stretching, Substrates, X ray absorption, X ray absorption fine structure spectroscopy, X ray photoelectron spectroscopy, X rays, Absorption spectroscopy
IdentifiersURN: urn:nbn:se:kth:diva-198753DOI: 10.1021/jp105696jISI: 000285818200024ScopusID: 2-s2.0-78651109268OAI: oai:DiVA.org:kth-198753DiVA: diva2:1059059
QC 201612222016-12-222016-12-212016-12-22Bibliographically approved