Molecular structure and spectra of danthron and emodin studied by FTIR, Raman spectroscopy and DFT techniques

In this work, experimental and theoretical studies on danthron emodin are presented. Experimentally, Fourier transform infrared (FTIR), Raman UV–Vis spectra of were recorded. The structure vibrational frequencies the molecules calculated using density functional theory (DFT) with B3LYP triple zeta (TZVP) basis set. Among various possible structures emodin, it was found that most stable involve intramolecular hydrogen bonds between two OH C=O groups. IR conformations correlate well their FTIR. Detailed frequency analysis done for all modes obtained assigned to ring vibrations along stretching bending specific bond vibrations. bands from FTIR both data.