Surface-Enhanced Raman Scattering of 4-Cyanobiphenyl on Gold and Silver Nanoparticle Surfaces

Abstract

The adsorption behavior of 4-cyanobiphenyl (CNBP) has been investigated by means of surface-enhanced Raman scattering (SERS). CNBP appeared to assume a tilted orientation on silver and gold. The presence of the ring C-H band denoted a rather vertical orientation of the biphenyl ring on Ag and Au. On the other hand, considerable red shifts of the ring-breathing modes with the increase in their bandwidths indicated a substantial π-type interaction between the benzene rings and metal substrates. On gold, the concentrationdependent SERS experiment showed CNBP to have a slightly perpendicular stance at its high surface coverage. The presence of the BH4ion in sols was found to affect the adsorption reaction and surface orientation of CNBP. The spectral band analysis based on electromagnetic selection rule indicated that CNBP should have a slightly more vertical orientation on gold than on silver at the concentration of ∼10 -4 M.

Tautomerism of Cytosine on Silver, Gold, and Copper: Raman Spectroscopy and Density Functional Theory Calculation Study

“…10 The concentration of cytosine in the aqueous solution was 10 -3 M. This concentration should correspond to cytosine on metal surface at the concentration above a full-coverage limit by assuming that the adsorbate was oriented perpendicularly with respect to the colloidal surfaces. [25][26][27][28][29] Our spectrum on Ag appeared to be consistent with this report. 10 It has been admitted that the colloidal conditions for Ag, Au, and Cu nanoparticle solutions may be not be adequate to discuss the tautomerism of cytosine.…”

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

“…[20][21][22][23][24][25][26][27] Recently a density functional theory study was performed to investigate the adsorption of alkanethiols on Cu, Ag, and Au surfaces, predicting dissimilar ionic characteristics depending on the metal substrates. 28 Solvent dependent charge transfer of the ruthenium bipyridine (Ru-bpy) dye on colloidal Ag and Au surface has been recently reported by means of SERS.…”

“…28 Solvent dependent charge transfer of the ruthenium bipyridine (Ru-bpy) dye on colloidal Ag and Au surface has been recently reported by means of SERS. 29 Although quite a few studies have explored the different adsorption structures of SAMs on metal surfaces, [20][21][22][23][24][25][26][27][28] no reports have investigated ruthenium bipyridine (Ru-bpy) dye on metal surfaces using potential dependent vibrational spectroscopy.…”

Exploring the alignment of carbon nanotubes dispersed in a liquid crystal matrix using coplanar electrodes

“…The higher intensity Raman bands are assigned to the biphenyl ring deformations and the assignment of such modes has been performed by taking into account that biphenyl belongs to the C 2v point group. 39 The mode at 2226 cm À1 is assigned to CN stretching, while the mode at 1606 cm À1 is assigned to C¼C stretching in the rings. The modes at 1178 and 1284 cm À1 are both assigned to C-H bending plus deformation of the biphenyl rings.…”