Adsorption of some benzohydroxamic acid derivatives on copper oxide: assignment and interpretation of SERS spectra

Abstract

The general aim of this work is to obtain information about the adsorption geometry of several benzohydroxamic acid (BHA) derivatives deposited on copper oxide. The investigation is done by means of surface enhanced Raman spectroscopy (SERS). In order to interpret the experimental information, an assignment of the SERS spectra is carried out. The process of assignment is supported by theoretical spectra derived from quantum-chemical calculations. As the size of the molecules and the overall lack of symmetry of the adsorbate-substrate system hinder the transparent description of the molecular vibrations, the local symmetry of the benzene is used as a basic classification feature. Such an approach is justified because, according to the theoretical spectra, the vibrations typical for the free benzene ring are conserved in the studied molecules. The deformations of the substituent and hydroxamic groups are added as a secondary descriptive element. On the basis of the spectrum assignment, the common vibrations typical for all investigated compounds and those used for identification that are pertinent to each of them, are classified. The surface selection rule is then qualitatively applied in order to derive information about the adsorption geometry.

A Molecular-Scale Approach to Rare-Earth Beneficiation: Thinking Small to Avoid Large Losses

“…However, the positions of some bands differ from those in the solution-phase spectrum, indicative of different strengths of interaction. Differences in interaction strength between BHA and metal ions in solution and at surfaces are also reported in the literature ( Blajiev et al., 2006 ). The band at 1,494 cm −1 ( Blajiev et al., 2006 ) suggests an involvement of the hydroxamate moiety in the interaction with the surface, consistent with ATR-FTIR and DFT results.…”

Fabrication of one-dimensional ZnO/4-Mpy/Ag assemblies and their spectroscopic studies

“…Based on the previous report, the SERS enhancement for Ag nanoparticles is attributed to the electromagnetic and chemical enhancement mechanism [19][20][21][22][23]. On the other hand, many groups have reported that semiconductor can give rise to the enhanced Raman scattering of adsorbed molecules and the main contribution come in on chemical mechanism [24,25]. Furthermore, our group observed the SERS effect with 10 2 -10 3 orders of magnitude for CuO and ZnS nanocrystals [14,15].…”

Enhanced Raman Scattering as a Probe for 4-Mercaptopyridine Surface-modified Copper Oxide Nanocrystals

“…6 The application fields of CuO nanocrystals are strongly dependent on its fundamental properties. Up to now, there are only a few reports 7,8 about CuO or, Cu2O with surface-enhanced Raman scattering (SERS) properties; however, the enhancement ability is ambiguous.…”