Cargando…
Molecular Structures and Spectral Properties of Natural Indigo and Indirubin: Experimental and DFT Studies
This paper presents a comparative study on natural indigo and indirubin in terms of molecular structures and spectral properties by using both computational and experimental methods. The spectral properties were analyzed with Fourier transform infrared (FTIR), Raman, UV-Visible, and fluorescence tec...
Autores principales: | , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2019
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6865026/ https://www.ncbi.nlm.nih.gov/pubmed/31652913 http://dx.doi.org/10.3390/molecules24213831 |
_version_ | 1783472013356040192 |
---|---|
author | Ju, Zixin Sun, Jie Liu, Yanping |
author_facet | Ju, Zixin Sun, Jie Liu, Yanping |
author_sort | Ju, Zixin |
collection | PubMed |
description | This paper presents a comparative study on natural indigo and indirubin in terms of molecular structures and spectral properties by using both computational and experimental methods. The spectral properties were analyzed with Fourier transform infrared (FTIR), Raman, UV-Visible, and fluorescence techniques. The density functional theory (DFT) method with B3LYP using 6-311G(d,p) basis set was utilized to obtain their optimized geometric structures and calculate the molecular electrostatic potential, frontier molecular orbitals, FTIR, and Raman spectra. The single-excitation configuration interaction (CIS), time-dependent density functional theory (TD-DFT), and polarization continuum model (PCM) were used to optimize the excited state structure and calculate the UV-Visible absorption and fluorescence spectra of the two molecules at B3LYP/6-311G(d,p) level. The results showed that all computational spectra agreed well with the experimental results. It was found that the same vibrational mode presents a lower frequency in indigo than that in indirubin. The frontier molecular orbital analysis demonstrated that the UV-Visible absorption and fluorescence bands of indigo and indirubin are mainly derived from π → π* transition. The results also implied that the indigo molecule is more conjugated and planar than indirubin, thereby exhibiting a longer maximum absorption wavelength and stronger fluorescence peak. |
format | Online Article Text |
id | pubmed-6865026 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-68650262019-12-06 Molecular Structures and Spectral Properties of Natural Indigo and Indirubin: Experimental and DFT Studies Ju, Zixin Sun, Jie Liu, Yanping Molecules Article This paper presents a comparative study on natural indigo and indirubin in terms of molecular structures and spectral properties by using both computational and experimental methods. The spectral properties were analyzed with Fourier transform infrared (FTIR), Raman, UV-Visible, and fluorescence techniques. The density functional theory (DFT) method with B3LYP using 6-311G(d,p) basis set was utilized to obtain their optimized geometric structures and calculate the molecular electrostatic potential, frontier molecular orbitals, FTIR, and Raman spectra. The single-excitation configuration interaction (CIS), time-dependent density functional theory (TD-DFT), and polarization continuum model (PCM) were used to optimize the excited state structure and calculate the UV-Visible absorption and fluorescence spectra of the two molecules at B3LYP/6-311G(d,p) level. The results showed that all computational spectra agreed well with the experimental results. It was found that the same vibrational mode presents a lower frequency in indigo than that in indirubin. The frontier molecular orbital analysis demonstrated that the UV-Visible absorption and fluorescence bands of indigo and indirubin are mainly derived from π → π* transition. The results also implied that the indigo molecule is more conjugated and planar than indirubin, thereby exhibiting a longer maximum absorption wavelength and stronger fluorescence peak. MDPI 2019-10-24 /pmc/articles/PMC6865026/ /pubmed/31652913 http://dx.doi.org/10.3390/molecules24213831 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Ju, Zixin Sun, Jie Liu, Yanping Molecular Structures and Spectral Properties of Natural Indigo and Indirubin: Experimental and DFT Studies |
title | Molecular Structures and Spectral Properties of Natural Indigo and Indirubin: Experimental and DFT Studies |
title_full | Molecular Structures and Spectral Properties of Natural Indigo and Indirubin: Experimental and DFT Studies |
title_fullStr | Molecular Structures and Spectral Properties of Natural Indigo and Indirubin: Experimental and DFT Studies |
title_full_unstemmed | Molecular Structures and Spectral Properties of Natural Indigo and Indirubin: Experimental and DFT Studies |
title_short | Molecular Structures and Spectral Properties of Natural Indigo and Indirubin: Experimental and DFT Studies |
title_sort | molecular structures and spectral properties of natural indigo and indirubin: experimental and dft studies |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6865026/ https://www.ncbi.nlm.nih.gov/pubmed/31652913 http://dx.doi.org/10.3390/molecules24213831 |
work_keys_str_mv | AT juzixin molecularstructuresandspectralpropertiesofnaturalindigoandindirubinexperimentalanddftstudies AT sunjie molecularstructuresandspectralpropertiesofnaturalindigoandindirubinexperimentalanddftstudies AT liuyanping molecularstructuresandspectralpropertiesofnaturalindigoandindirubinexperimentalanddftstudies |