Intramolecular hydrogen bonding in myricetin and myricitrin. Quantum chemical calculations and vibrational spectroscopy

• Published in: Journal of molecular structure Vol. 1131; pp. 242 - 249
• Main Authors: Vojta, Danijela, Dominković, Katarina, Miljanić, Snežana, Spanget-Larsen, Jens
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.03.2017
• Subjects: Density functional theory (DFT) calculations; FT-IR and FT-Raman spectra; Intramolecular hydrogen bonding; Myricetin; Myricitrin; OH stretching frequencies; Intramolecular hydrogen bonding; Density functional theory (DFT) calculations; FT-IR and FT-Raman spectra; Myricetin; Myricitrin; OH stretching frequencies
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2016.11.069

The molecular structures of myricetin (3,3′,4′,5,5′,7-hexahydroxyflavone; MCE) and myricitrin (myricetin 3-O-rhamnoside; MCI) are investigated by quantum chemical calculations (B3LYP/6-311G**). Two preferred molecular rotamers of MCI are predicted, corresponding to different conformations of the O-rhamnoside subunit. The rotamers are characterized by different hydrogen bonded cross-links between the hydroxy groups of the rhamnoside substituent and the parent MCE moiety. The predicted OH stretching frequencies are compared with vibrational spectra of MCE and MCI recorded for the sake of this investigation (IR and Raman). In addition, a reassignment of the CO stretching bands is suggested. [Display omitted] •Experimental IR and Raman spectra of myricetin and myricitrin.•Molecular structures of myricetin and myricitrin obtained from DFT calculations.•Molecular shape of myricitrin determined by intramolecular H-bonding.•Computed OH stretching frequencies compared with experimental IR transitions.•Reassignment of CO stretching bands is suggested.