title: Conformational analysis and vibrational study of daidzein by using FT-IR and FT-Raman spectroscopies and DFT calculations.
abstract: Daidzein (C15H10O4) is a type of isoflavone. It was isolated from Butea monosperma that belongs to the Fabaceae family. Soybeans and soy products are the abundant source of daidzein. It is the subject of investigation for many reasons, as it has got wide applications, such as anti-tumor, anti-estrogen, weak pro-estrogen and anti-cancer activities. In the present study, a complete vibrational assignment is provided for the observed IR and Raman spectra of daidzein. Electronic properties have been analyzed using TD-DFT method for both gaseous and solvent phase. The optimized geometry, total energy, potential energy surface and vibrational wavenumbers of daidzein have been determined using density functional theory (DFT/B3LYP) method with 6-311++G(d,p) basis set and a good correlation was found between observed and calculated values. The double well potential energy curve of the molecule about three bonds, has been plotted, as obtained from DFT/6-31G basis. The HOMO-LUMO energy gap of possible conformers has been calculated for comparing their chemical activity. Global reactivity descriptors have been calculated for predicting the chemical reactivity and the stability of chemical systems. Electrostatic potential surface has been plotted for predicting the structure activity relationship. NBO analysis has also been performed to study the stability of the molecule. NLO study reveals the nonlinear properties of the molecule. 1H and 13C NMR spectra have also been studied. Finally, the calculated results were used to simulate infrared and Raman spectra of the title compound which showed a good agreement with the observed spectra.
authors.affiliation: Department of Physics, University of Lucknow, Lucknow 226007, India.
authors.forename: Harshita
authors.initials: H
authors.lastname: Singh
authors.affiliation: Department of Physics, University of Lucknow, Lucknow 226007, India.
authors.forename: Swapnil
authors.initials: S
authors.lastname: Singh
authors.affiliation: Department of Physics, University of Lucknow, Lucknow 226007, India.
authors.forename: Anubha
authors.initials: A
authors.lastname: Srivastava
authors.affiliation: Department of Physics, University of Lucknow, Lucknow 226007, India. Electronic address: poonam_tandon@hotmail.com.
authors.forename: Poonam
authors.initials: P
authors.lastname: Tandon
authors.affiliation: Department of Physics, University of Lucknow, Lucknow 226007, India.
authors.forename: Purnima
authors.initials: P
authors.lastname: Bharti
authors.affiliation: Medicinal and Process Chemistry Division, Central Drug Research Institute (CDRI), Lucknow 226031, India.
authors.forename: Sudhir
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Medicinal and Process Chemistry Division, Central Drug Research Institute (CDRI), Lucknow 226031, India.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Maurya
mesh_terms: D007887:Fabaceae / Q000737:chemistry*; D006131:Growth Inhibitors / Q000737:chemistry*; D007529:Isoflavones / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman
chemical_list: D006131:Growth Inhibitors; D007529:Isoflavones; C004742:daidzein
keywords: DFT; Daidzein; HOMO–LUMO; IR and Raman spectroscopy; NBO analysis; NLO