Self-assembled monolayers of benzylmercaptan and para-cyanobenzylmercaptan on gold: surface infrared spectroscopic characterization

Abstract

Self-assembled monolayers (SAMs) on gold substrates were prepared from benzylmercaptan (BM) and para-cyanobenzylmercaptan (pCBM), and the resulting surfaces were investigated using conventional infrared reflection-absorption spectroscopy (IRRAS) as well as polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS). IRRAS data are analyzed by comparison with transmission IR spectra and theoretical (DFT) simulations. The spectroscopic results indicate the presence of well-ordered monolayers of BM and pCBM with an orientation perpendicular to the surface. IRRAS and PM-IRRAS data are compared to each other and the respective merits of both methods are discussed.

Reactions of Rh2(CH3COO)4with thiols and thiolates: a structural study

“…S6; literature values 2547-2557 cm À1 ) (Nikolić et al, 2014;Zhang et al, 2013), suggesting that the S-H bond becomes weaker upon coordination of DHLA to the axial positions of Rh 2 (AcO) 4 . Also the S-H stretching frequency for benzylthiol coordinated in [Rh 2 (AcO) 4 (HSCH 2 Ph) 2 ] (2550 cm À1 ) shows a similar shift relative to that of pure benzylthiol (2565 cm À1 ) (Christoph & Tolbert, 1980;Rajalingam et al, 2010). It is unlikely that the DHLA carboxyl group is involved in any bonding interaction in this compound, e.g.…”

Monitoring Solid‐Phase Reactions in Self‐Assembled Monolayers by Surface‐Enhanced Raman Spectroscopy

“…In that respect, infrared (IR) spectroscopy and variants thereof including Fourier-transform IR (FTIR) spectroscopy,polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) are sensitive enough to measure solid thin films to provide information about the chemical functional groups present in aS AM. [17][18][19][20] Raman spectroscopy is an optical characterization method that relies on inelastic scattering of incident, monochromatic light at chemical bonds.I tc an therefore provide substantial information about the chemical composition of the specimen, [21] at least for Raman-active bonds. Contrary to IR spectroscopy,w here bonds with large dipole moments exhibit the highest signal intensities,bonds that are non-polar and polarizable are generally highly Raman-active.…”

“…While these methods provide the above‐mentioned information about a surface, many of them lack the ability to characterize the chemical composition of a surface, e.g., to detect functional groups within the SAM. In that respect, infrared (IR) spectroscopy and variants thereof including Fourier‐transform IR (FTIR) spectroscopy, polarization‐modulation infrared reflection–absorption spectroscopy (PM‐IRRAS) are sensitive enough to measure solid thin films to provide information about the chemical functional groups present in a SAM [17–20] . Raman spectroscopy is an optical characterization method that relies on inelastic scattering of incident, monochromatic light at chemical bonds.…”

Reaktionsverfolgung von Festphasensynthesen in selbstassemblierenden Monolagen mit oberflächenverstärkter Raman‐Spektroskopie

“…Obwohl mit diesen Methoden die in Klammern genannten Charakteristika einer Oberfläche ermittelt werden können, sind die meisten davon nicht in der Lage, die chemische Zusammensetzung einer Oberfläche zu bestimmen, zum Beispiel für den Nachweis funktioneller Gruppen innerhalb der SAM. Die Infrarotspektroskopie (IR‐Spektroskopie) und deren Abwandlungen, zum Beispiel die Fourier‐Transform‐Infrarotspektroskopie (FTIR) oder die polarisationsmodulierte Infrarot‐Reflexions‐Absorptions‐Spektroskopie (PM‐IRRAS), sind sensitiv genug, um feste Dünnschichten zu analysieren und die chemischen funktionellen Gruppen in einer SAM zu ermitteln [17–20] . Die Raman‐Spektroskopie ist eine auf unelastischer Streuung von einfallendem monochromatischem Licht an chemischen Bindungen beruhende optische Charakterisierungsmethode.…”