TY - JOUR
T1 - Synchrotron radiation linear dichroism (SRLD) investigation of the electronic transitions of quinizarin, chrysazin, and anthrarufin
AU - Nguyen, Duy Duc
AU - Jones, Nykola Clare
AU - Hoffmann, Søren Vrønning
AU - Spanget-Larsen, Jens
PY - 2010
Y1 - 2010
N2 - The electronic transitions of the three α,α'-dihydroxy derivatives of anthraquinone, 1,4‑dihydroxy‑, 1,8-dihydroxy-, and 1,5-dihydroxy-9,10-anthraquinone (quinizarin, chrysazin, and anthrarufin), were investigated by synchrotron radiation linear dichroism (SRLD) spectroscopy on samples aligned in stretched polyethylene. With synchrotron radiation, polarization data could be determined in the UV region up to ca. 58000 cm-1 (7.2 eV), which amounts to an extension by ca. 11000 cm-1 (1.4 eV) relative to the range accessible with a conventional light source. Throughout the investigated region (15000 - 58000 cm-1), essentially similar wavenumbers, intensities, and transition moment directions were determined for chrysazin and anthrarufin, while the spectrum of quinizarin deviated significantly. The results of time-dependent density functional theory (TD-DFT) calculations were in good agreement with the experimental spectra, leading to the assignment of 10 electronic states for quinizarin, and 8 electronic states for chrysazin and anthrarufin. No evidence was found for contributions from different tautomeric or rotameric forms to the observed spectra.
AB - The electronic transitions of the three α,α'-dihydroxy derivatives of anthraquinone, 1,4‑dihydroxy‑, 1,8-dihydroxy-, and 1,5-dihydroxy-9,10-anthraquinone (quinizarin, chrysazin, and anthrarufin), were investigated by synchrotron radiation linear dichroism (SRLD) spectroscopy on samples aligned in stretched polyethylene. With synchrotron radiation, polarization data could be determined in the UV region up to ca. 58000 cm-1 (7.2 eV), which amounts to an extension by ca. 11000 cm-1 (1.4 eV) relative to the range accessible with a conventional light source. Throughout the investigated region (15000 - 58000 cm-1), essentially similar wavenumbers, intensities, and transition moment directions were determined for chrysazin and anthrarufin, while the spectrum of quinizarin deviated significantly. The results of time-dependent density functional theory (TD-DFT) calculations were in good agreement with the experimental spectra, leading to the assignment of 10 electronic states for quinizarin, and 8 electronic states for chrysazin and anthrarufin. No evidence was found for contributions from different tautomeric or rotameric forms to the observed spectra.
KW - Hydroxy-anthraquinones
KW - Electronic transitions
KW - Synchrotron radiation
KW - Linear dichroism (LD)
KW - Polarization directions
KW - Transition moments
KW - Time-dependent density functional theory (TD-DFT)
U2 - 10.1016/j.saa.2010.05.023
DO - 10.1016/j.saa.2010.05.023
M3 - Journal article
SN - 1386-1425
VL - 77
SP - 279
EP - 286
JO - Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
JF - Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
IS - 1
ER -