Binding property and structure of aromatic isocyanide self‐assembly monolayers on Ag and Au surfaces

Abstract

The binding property of p-biphenyl isocyanide self-assembled monolayers (SAMs) on Au and Ag was investigated by temperature-dependent surface-enhanced Raman spectroscopy (SERS). p-Biphenyl isocyanide was found to desorb on Ag at a low temperature of ∼393 K whereas it appeared to remain enduring at a high temperature of ∼453 K for Au. Structures of p-biphenyl isocyanide SAMs on Au and Ag flat films were checked by means of near-edge x-ray absorption fine structure spectroscopy (NEXAFS) at the two different normal (90• ) and grazing (20 • ) angles of the incident x-ray beam. Our results suggested that the SAMs prepared by p-biphenyl isocyanide should have a relatively disordered structure even at room temperature on both Au and Ag, as indicated from an insubstantial change in NEXAFS spectra at the two different angles from those of p-biphenyl thiolate and p-biphenyl methanethiolate. The weakness of the isocyanide-metal bond in comparison with the sulphur-metal bond may result in both low surface coverage and orientational disorder. A density functional theory calculation method was employed to attempt to explain the difference in stability for phenyl isocyanide on Ag and Au surfaces. Our calculation result yielded a lower binding energy of phenyl isocyanide on Ag than that on Au, consistent with the temperature-dependent Raman results.

Investigation of the Adsorption and Self Assembly of Isocyanide Derivatives on Au(111) Surface

“…Recently a few theoretical researches were conducted on the adsorption of isocyanide on gold. [22][23][24] Seminario and coworkers 22 studied the adsorption of the isocyanide using three gold clusters. The DFT calculations showed that the binding was to a single Au atom for each gold cluster, but the binding to the bridge and hollow sites on the Au(111) surface was not observed.…”

Infrared Spectroscopic Study of α-Cyano-4-hydroxycinnamic Acid on Nanocrystalline TiO2Surfaces: Anchoring of Metal-Free Organic Dyes at Photoanodes in Dye-Sensitized Solar Cells

“…7 In addition temperature-dependent interfacial vibrational spectroscopic tools can provide information on the energetics or phase transition of adsorbates on surfaces. [8][9][10] Despite several spectroscopic reports on Ruthenim (II) complexes, [11][12][13][14] there has not been either investigation on the spectroscopic study or the thermal degradation and the resulting change in molecular architecture in detail for a cyanoacrylic acid film fabricated on the TiO2 surfaces to the best of our knowledge. In this present work, temperature-dependent diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy was applied to understand the nature of adsorption and structural change of α-cyano-4-hydroxycinnamic acid (CHCA) on the TiO2 surfaces.…”

Electric Field-induced Charge Transfer of (Bu4N)2[Ru(dcbpyH)2-(NCS)2] on Gold, Silver, and Copper Electrode Surfaces Investigated by Means of Surface-enhanced Raman Scattering

“…7 The analysis of spectral features has provided information on adsorption, chemical reactions, and vibrational structures on surfaces. [8][9][10][11][12][13][14] Self-assembly methods represent a unique way to create well-defined nanostructures and thus control surface properties. 15 Characterization of self-assembled monolayers (SAMs) can provide detailed information on the chemical interactions and transformations occurring at surfaces.…”