New Insights on the Raman and SERS Spectra of Luteolin under Different Excitation Conditions: Experiments and DFT Calculations

• DOI: 10.3390/chemosensors11020104
• Publication Date: 2023-02-02T06:53:54Z
• Authors: Marilena Ricci; Emilio Mario Cast...; Silvia Innocenti; Maurizio Becucci
• Keywords: Excitation wavelength

We have studied, by density functional theory, the interaction between luteolin and Ag, devising two complexes where an Ag14 cluster faces different sites of molecule. The are identified as quinoid-like cathecol-like, CPLX1 CPLX2, respectively. Raman SERS spectra were measured at excitation wavelengths. Luteolin solid samples from suppliers spectra, possibly associated with arrangements in solids. These well reproduced our DFT calculations. Assignment vibrational modes luteolin–Ag14 is obtained thanks to decomposition normal coordinates terms internal coordinates. calculated spectrum for seems better reproduce experimental spectra. CPLX2 furnishes a still resembling that high frequency region responsible some weak bands 1400–1700 cm−1 range cannot be accounted system. dependent on wavelength. calculation electronic suggests presence charge-transfer states, which might changes