Vibrational characterization and adsorption mode on SERS-active surfaces of guanidino-(bromophenyl)methylphosphonic acid

Abstract

This work presents adsorption geometry of [N-butyl-guanidino-(4-bromophenyl)methyl] phosphonic acid (4-BrPhG(n-But)P) on different SERS-active substrates (colloidal and specifically prepared Ag and Au roughened substrates). The adsorption mode is deduced from the SERS selection rules and several characteristic bands of the 4-BrPhG(n-But)P molecular fragments. The SERS spectra are compared to the experimental FT-Raman spectrum. In addition, the vibrational wavenumbers and PED's obtained for 4-BrPhG(n-But)P by using density functional theory methods with B3LYP/6-311++G(**) level of theory and PCM model is briefly presented.

Keywords: 4-BrPhG(n-But)P; AFM; Ag and Au; Ag and Au SERS-active substrate; Atomic force microscopy, AFM; DFT; Density functional theory, DFT; FT-RS; Fourier-transform Raman spectroscopy; Fourier-transform Raman spectroscopy, FT-RS; SERS; SERS-active substrates; Surface-enhanced Raman spectroscopy, SERS; [N-butyl-guanidino-(4-bromophenyl)methyl]phosphonic acid; [N-butyl-guanidino-(4-bromophenyl)methyl]phosphonic acid, 4-BrPhG(n-But)P; atomic force microscopy; density functional theory; surface-enhanced Raman spectroscopy.