Raman and Surface Enhanced Raman Scattering of 3-Hydroxyflavone

Abstract

Normal Raman (NR) and surface enhanced Raman scattering (SERS) spectra of 3-hydroxyflavone (3-HF) have been measured. The SERS spectra are obtained both on an electrode surface and on Ag colloid. Spectral bands are assigned using DFT calculations for the NR, SERS, and FTIR spectra. The IR, normal Raman, and SERS results are compared and in conjunction with a DFT calculation are used to interpret the low-frequency carbonyl stretching vibration in 3-HF. The experimental results support the DFT geometry calculations, which show that an adatom site at the vertex of Ag20 cluster binding with the 3-HF molecular plane tilted at an angle of about 53° to the surface is a low-energy structure. This is consistent with the enhancement of in-plane vibrational modes.

Historical organic dyes: a surface‐enhanced Raman scattering (SERS) spectral database on Ag Lee–Meisel colloids aggregated by NaClO4

“…[43] As shown by the literature data, if an excitation wavelength of 785 nm is used, a partly different spectrum is obtained. [6,43] The observed spectral pattern is indeed similar to that of morin, and the most intense bands at 1408 and 1314 cm −1 , assigned to the 3 O-H bending as well as to aromatic ring vibrations, [8,41] allow us to suggest also for this molecule a coordination with the 3-hydroxy-4-keto-group to the metal surface. Moreover, as the signals at 1262 and 1120 cm −1 , attributed to the 3 and 4 O-H in-plane bending, [8,44] are only observed in the spectrum of quercetin, a second kind of coordination with the 3 ,4 -dihydroxyl group could be suggested for this latter molecule.…”

“…4(a) and (b)), for which the SERS vibrational wavenumbers have been previously published. [6] The observed spectral pattern, in which the intense bands located at about 1388 and 1315 cm −1 are assigned to the 3 O-H bending as well as to aromatic ring vibrations, [8,41] allows us to suggest for this molecule a coordination with the 3-hydroxy-4-keto-group to the metal surface. The proposed coordination mode of morin with respect to the metal surface is supported by structural studies of metal complexes involving such molecule.…”

Luminescent 3-hydroxyflavone nanocomposites with a tuneable refractive index for photonics and UV detection by plasma assisted vacuum deposition

“…2 in comparison with the spectrum of 3-HF powder in KBr. The latter depicts the characteristics IR features of the 3-hydroxyflavone molecule, [49][50][51][52][53][54] which have been attributed as reported in Table S1 provided as supporting information. The IR spectra of the plasma films reproduce most of the 3-HF bands (e.g., peaks at 1609, 1561, 760 and 700 cm -1 ).…”

Extractionless non‐hydrolysis surface‐enhanced Raman spectroscopic detection of historical mordant dyes on textile fibers

“…Different SERS substrates have been employed, mostly silver colloids reduced with citrate, [14,15,17 -19,21 -34] hydroxylamine [16,22,23,28] or borohydride. [33] But other substrates have been tested as well: electrodes, [13,26] Ag-Al 2 O 3 35 , Tollens mirrors, [31,35] vacuum-evaporated silver nano-island films (AgIF), [31,36] e-beam-deposited AgIF, [37] silver films over nanospheres (AgFON), [38] and Ag nanoparticles obtained in situ by laser photoreduction. [20,39] SERS spectra of dyestuffs other than anthraquinones and flavonoids (redwoods, naftoquinones and orchil dyes, [31,37] melanin sepia [33] ) have been recorded using such SERS substrates.…”