Spectroscopic features of caffeic acid: Theoretical study

Abstract

ABSTRACT. In order to investigate spectroscopic features of caffeic acid (CA), the IR, Raman, 13 C-NMR, 1 H-NMR, and UV spectra of this compound were simulated. For this purpose the B3LYP-D3/6-311+G(d,p) theoretical model was used in combination with CPCM solvation model. Very good agreement between all experimental and simulated spectra was achieved. This result indicates that B3LYP-D3 can be a method of choice in studies that refer to spectroscopic investigations. Spectroscopic features of CA are very similar to those of chlorogenic acid (5-O-caffeoylquinic acid) (MARKOVIĆ, TOŠOVIĆ and DIMITRIĆ MARKOVIĆ, 2016), pointing out the significance of caffeic moiety.

New SiO2/Caffeic Acid Hybrid Materials: Synthesis, Spectroscopic Characterization, and Bioactivity

“…Briefly, it is mainly characterized by four absorption bands at 324, 296, 242, and 216 nm. The n→π* and π→π* electronic transitions referring to the C=O group were responsible for the absorption at 296 and 216 nm, respectively, whereas the bands at 242 and 324 were attributable to the π→π* transitions of the aromatic moiety [25]. At the considered caffeic acid concentration (3.5 × 10 −5 mol•L −1 ) the band at the lowest wavelength was the most intense.…”

“…To this aim, the FT-IR spectra of silica gel (SiO 2 ) and pure caffeic acid (CAF) were compared to those recorded for the hybrid materials (SiO 2 /caffeic acid at different wt.%) (Figures 2 and 3). The spectral assignments of the phenol compound were based on previous literature data [25,26]. The intense bands in the FT-IR spectrum of pure caffeic acid (Figure 2a) between 4000 and 2600 cm −1 were assigned to the OH stretching vibrations, which partially overlaied the weak CH stretching modes of the benzene moiety and acyclic chain.…”

Thermal Transformation of Caffeic Acid on the Nanoceria Surface Studied by Temperature Programmed Desorption Mass-Spectrometry, Thermogravimetric Analysis and FT–IR Spectroscopy

“…It was attributed [43] to the stretching vibrations of the double bonds C=C. However, most researchers attribute this band to νC=O [39,41,42,44]. (96%) with an appropriate concentration.…”

New SiO₂/Caffeic Acid Hybrid Materials: Synthesis, Spectroscopic Characterization and Bioactivity

“…Breefly, it is mainly characterized by four absorption bands at 324, 296, 242 and 216 nm. The nπ* and π π* electronic transitions referred to the C=O group are responsible for the absorption at 296 and 216 nm, respectively, whereas the bands at 242 and 324 are attributable to the π π* transitions of the aromatic moiety [25]. At the considered caffeic acid concentration (3.5·10 -5 mol L -1 ) the band at the lowest wavelength is the most intense.…”

“…To this aim, the FT-IR spectra of silica gel (SiO2) and pure caffeic acid (CAF) were compared to those recorded for the hybrid materials (SiO2/caffeic acid at different wt%) (Figure 2 and 3). The spectral assignments of the phenol compound were based on previous literature data [25,26]. The intense bands in the FT-IR spectrum of pure caffeic acid (Figure 2a) between 4000 and 2600 cm -1 were assigned to the OH stretching vibrations, which partially overlaied the weak CH streching modes of benzene moiety and acyclic chain.…”