Vibrational spectrum and torsional potential of 2-methoxy-3-methyl-1,4-benzoquinone
Article Abstract:
Research was conducted to examine the stable conformations and vibrational spectra of 2-methody-3-methyl-1,4-benzoquinone via density functional methods. The calculations reveal how sensitive the energetics of the methoxy group orientation as well as relative energies of stable conformations can depend on protein-chromophore interactions. Findings confirm previously reported speculations that the different properties of Q(sub A) and Q(sub B) in the photosynthetic reaction center of Rhodobacter sphaeroides could be caused by different methoxy group orientations due to differences in protein-chromophore interactions.
Publication Name: Journal of Physical Chemistry B
Subject: Chemicals, plastics and rubber industries
ISSN: 1520-6106
Year: 1999
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A density functional investigation of model molecules for ubisemiquinone radical anions
Article Abstract:
Density functional calculations were used to investigate the structures, force constants, vibrational spectra and isotropic hyperfine coupling constants of the radical anions 2,3-dimethoxy-1,4-benzoquinone and 2,3-dimethoxy-5,6-dimethyl-1,4-benzoquinone. The impact of the methoxy group orientation on the vibrational spectrum and force constants was found to be less pronounced than in the corresponding neutral molecules. The frequency differences occurring in various reaction centers of binding sites seem to be due to differences of electrostatic quinone-protein interactions.
Publication Name: Journal of Physical Chemistry B
Subject: Chemicals, plastics and rubber industries
ISSN: 1520-6106
Year: 1998
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Structures and vibrational frequencies of the quinones in Rb. sphaeroides derived by a combined density functional/molecular mechanics approach
Article Abstract:
The structures of the ubiquinones Q(sub A) and Q(sub B) in the bacterial photosynthetic reaction center of Rhodobacter sphaeroides calculated by a quantum mechanical/molecular mechanics hybrid technique. Calculation of the vibrational spectra reveals that one C=O stretching mode of Q(sub A) is considerably shifted to lower frequencies in agreement with the experimental data.
Publication Name: Journal of Physical Chemistry B
Subject: Chemicals, plastics and rubber industries
ISSN: 1520-6106
Year: 2003
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