Does Solvent Influence the Ground-state Tautomeric Population of Hypericin?¶

Wen, Jin; Chowdhury, P. K.; Fulton, D. Bruce; Datta, Anindya; Das, Kaustuv; Andreotti, Amy H.; Petrich, Jacob W.

doi:10.1562/0031-8655(2003)077<0005:dsitgs>2.0.co;2

Cited by 7 publications

(3 citation statements)

References 22 publications

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“…2), they do share the common feature of extended absorption from the visible to the UV. There is growing evidence from NMR (77,78), calculations (79), and spectroscopic studies of the separated hypericin enantiomers (80) that the complexity of the hypericin absorption spectrum does not arise from inhomogeneity of the ground state. The calculations performed here for the dihydroxy and the dimethoxy perylene quinone spectra can be explained in terms of transitions to a manifold of excited singlet states.…”

Section: Discussionmentioning

confidence: 99%

Synthesis of Hydroxy and Methoxy Perylene Quinones, Their Spectroscopic and Computational Characterization, and Their Antiviral Activity^¶

Krishnamoorthy¹,

Webb²,

Nguyen³

et al. 2005

Photochem & Photobiology

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Hydroxy and methoxy perylene quinones are synthesized in an attempt to isolate the essential spectroscopic and biological features of light‐induced antiviral agents such as hypericin and hypocrellin. Unlike their naturally occurring counterparts, these synthetic quinones bear the carbonyl, hydroxyl, and methoxy groups in the “bay region.” The hydroxy and methoxy compounds have rich absorption spectra with broad features in the visible (∼450–800 nm) and relatively more intense and narrow features at wavelengths ≤350 nm. High‐level ab initio quantum mechanical calculations assign the features in the absorption spectra to electronic transitions from So to S2 and to higher‐lying electronic states. The calculations indicate that in the ground state the trans dihydroxy isomer is 12.5 kcal/mol lower in energy than the cis dihydroxy isomer and is thus the only species present. The lowest‐energy trans methoxy ground state isomer and the lowest‐energy cis methoxy ground state isomer are found to be degenerate. An additional cis methoxy isomer 6.3 kcal/mol higher in energy than the global minimum is assumed to contribute to the spectrum and is also considered. Finally, the synthetic compounds exhibit similar light‐induced antiviral activity to each other, but significantly less than that of hypericin.

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Section: Discussionmentioning

confidence: 99%

Synthesis of Hydroxy and Methoxy Perylene Quinones, Their Spectroscopic and Computational Characterization, and Their Antiviral Activity^¶

Krishnamoorthy¹,

Webb²,

Nguyen³

et al. 2005

Photochem & Photobiology

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“…This study was motivated by the question of whether the rich and complicated spectra of hypericin can be attributed to ground‐state heterogeneity. Ab initio quantum mechanical calculations (38) and NMR experiments (37, 56) suggest that there is only one species in the ground state. Within experimental error, there is no difference between steady‐state spectra of the two enantiomers in any of the systems considered: ( S )‐(+)‐2‐butanol, γ‐cyclodextrin, HSA and GST.…”

Section: Discussionmentioning

confidence: 99%

The Separation of Hypericin's Enantiomers and Their Photophysics in Chiral Environments^¶

Sanders¹,

Halder²,

Xiao³

et al. 2005

Photochem & Photobiology

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We report the first separation of the enantiomers of hypericin. Their steady‐state optical spectra and ultrafast primary photoprocesses are investigated in chiral environments. Within experimental error, there is no difference between the two enantiomers in any of the systems considered. This is consistent with the emerging picture that the rich and extended absorption spectrum of hypericin is not a result of ground‐state heterogeneity. It is also consistent with the observation that the spectra and photophysics of hypericin are generally insensitive to environments in which it does not aggregate.

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Section: Scmentioning

confidence: 99%

Synthesis of Hydroxy and Methoxy Perylene Quinones, Their Spectroscopic and Computational Characterization, and Their Antiviral Activity

Krishnamoorthy¹,

Petrich²,

Webb³

et al. 2005

Photochem Photobiol

View full text Add to dashboard Cite

Hydroxy and methoxy perylene quinones are synthesized in an attempt to isolate the essential spectroscopic and biological features of light-induced antiviral agents such as hypericin and hypocrellin. Unlike their naturally occurring counterparts, these synthetic quinones bear the carbonyl, hydroxyl, and methoxy groups in the "bay region." The hydroxy and methoxy compounds have rich absorption spectra with broad features in the visible (approximately 450-800 nm) and relatively more intense and narrow features at wavelengths < or = 350 nm. High-level ab initio quantum mechanical calculations assign the features in the absorption spectra to electronic transitions from S0 to S2 and to higher-lying electronic states. The calculations indicate that in the ground state the trans dihydroxy isomer is 12.5 kcal/mol lower in energy than the cis dihydroxy isomer and is thus the only species present. The lowest-energy trans methoxy ground state isomer and the lowest-energy cis methoxy ground state isomer are found to be degenerate. An additional cis methoxy isomer 6.3 kcal/mol higher in energy than the global minimum is assumed to contribute to the spectrum and is also considered. Finally, the synthetic compounds exhibit similar light-induced antiviral activity to each other, but significantly less than that of hypericin.

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Does Solvent Influence the Ground-state Tautomeric Population of Hypericin?¶

Cited by 7 publications

References 22 publications

Synthesis of Hydroxy and Methoxy Perylene Quinones, Their Spectroscopic and Computational Characterization, and Their Antiviral Activity^¶

Synthesis of Hydroxy and Methoxy Perylene Quinones, Their Spectroscopic and Computational Characterization, and Their Antiviral Activity^¶

The Separation of Hypericin's Enantiomers and Their Photophysics in Chiral Environments^¶

Synthesis of Hydroxy and Methoxy Perylene Quinones, Their Spectroscopic and Computational Characterization, and Their Antiviral Activity

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Does Solvent Influence the Ground-state Tautomeric Population of Hypericin?¶

Cited by 7 publications

References 22 publications

Synthesis of Hydroxy and Methoxy Perylene Quinones, Their Spectroscopic and Computational Characterization, and Their Antiviral Activity¶

Synthesis of Hydroxy and Methoxy Perylene Quinones, Their Spectroscopic and Computational Characterization, and Their Antiviral Activity¶

The Separation of Hypericin's Enantiomers and Their Photophysics in Chiral Environments¶

Synthesis of Hydroxy and Methoxy Perylene Quinones, Their Spectroscopic and Computational Characterization, and Their Antiviral Activity

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Product

Resources

About

Synthesis of Hydroxy and Methoxy Perylene Quinones, Their Spectroscopic and Computational Characterization, and Their Antiviral Activity^¶

Synthesis of Hydroxy and Methoxy Perylene Quinones, Their Spectroscopic and Computational Characterization, and Their Antiviral Activity^¶

The Separation of Hypericin's Enantiomers and Their Photophysics in Chiral Environments^¶