Azobenzene-functionalized alkanethiols in self-assembled monolayers on gold

Abstract

Self-assembled monolayers (SAMs) of 4-trifluoromethyl-azobenzene-4 -methyleneoxy-alkanethiols (CF 3 -C 6 H 4 -N=N-C 6 H 4 -O-(CH 2 ) n -SH on (111)-oriented polycrystalline gold films on mica were examined by X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The spectra are analyzed with the help of density-functional-theory calculations of the isolated molecule. Only one doublet is detected in the sulphur 2p spectra of the investigated SAMs, consistent with a thiolate bond of the molecule to the gold surface. The C 1s XP spectra and the corresponding XAS π * resonance exhibit a rich structure which is assigned to the carbon atoms in the different chemical surroundings. Comparing XPS binding energies of the azobenzene moiety and calculated initial-state shifts reveals comparable screening of all C 1s core holes. While the carbon 1s XPS binding energy lies below the π * -resonance excitation-energy, the reversed order is found comparing core ionization and neutral core excitation of the nitrogen 1s core-hole of the azo group. This surprising difference in core-hole binding energies is interpreted

Photoinactivation of Candida albicans and Escherichia coli using aluminium phthalocyanine on gold nanoparticles

“…5(A) show the XPS spectra for S 2p analysis in which a doublet due to ‫2‬ ଷ/ଶ and ‫2‬ ଵ/ଶ was observed. The existence of the S 2p doublets is a result of the spin-orbit coupling [40]. The phthalocyanine alone showed two characteristic peaks at 161.0 and 162.4 eV.…”

Neuron‐like PC12 cell patterning on a photoactive self‐assembled monolayer

“…As shown in Figure , there were multiple overlapping peaks around 282.4 eV on the C 1s spectrum of (NVOC‐AUT)‐Au surface, an evidence of different carbon bonding present on (NVOC‐AUT)‐Au surface. For example, the peak at 282.4 eV was likely caused by the electron emission of the aromatic and aliphatic carbon; the shoulder peak at 283.9 eV could be attributed to carbon atoms connected to oxygen, nitrogen, and sulfur; the distinguishing peak at 287.1 eV was a shake‐up excitation caused by the π → π* transition in the aromatic ring . After UV irradiation, the disappearance of the broad π → π* transition peak at around 287.1 eV was the conclusive evidence to suggest the removal of caging agent, nitrobenzyl ring, from the surface.…”

“…p* transition in the aromatic ring. 27,28 After UV irradiation, the disappearance of the broad p ! p* transition peak at around 287.1 eV was the conclusive evidence to suggest the removal of caging agent, nitrobenzyl ring, from the surface.…”

Nitinol Modified by In Situ Generated Diazonium Salts as Adhesion Promoters for Photopolymerized Pyrrole

“…The ratio C oxidized /C is around 0.20 for bare NiTi and decreases down to 0.13 for NiTi|PD‐NH 2 . The peak at 291.7 eV is assigned to a shake‐up satellite (Figure ) originating from aromatic compounds, an additional confirmation of the PD‐NH 2 electrografting.…”