Acidic properties of hypericin and its octahydroxy analogue in the ground and excited states

pH dependent absorption and fluorescence spectra of hypericin 1 and its octahydroxy analogue 3 demonstrate their acidic properties, their deprotonation occuring in the ground and excited states from OH in the bay region and in the peri position to the carbonyl, respectively; the presence of the anion of 1 in the crystalline state is established by X-ray diffraction.

[1]  H. Falk,et al.  Tautomerism and stereochemistry of hypericin: Force field, NMR, and X-ray crystallographic investigations , 1993 .

[2]  F. Gai,et al.  Ultrafast excited-state processes in the antiviral agent hypericin , 1993 .

[3]  M. Gross,et al.  A new photoreceptor molecule from Stentor coeruleus , 1993 .

[4]  H. Falk,et al.  On the synthesis of hypericin by oxidative trimethylemodin anthrone and emodin anthrone dimerization: Isohypericin , 1992 .

[5]  H. Falk,et al.  On the nature of “soluble” hypericin inHypericum species , 1992 .

[6]  H. Falk,et al.  Deprotonation and protonation of hydroxyphenanthroperylenes , 1992 .

[7]  D. Häder,et al.  EFFECTS OF SOLAR RADIATION ON MOTILITY IN: Stentor coeruleus , 1991 .

[8]  B. K. Murray,et al.  In vitro virucidal activity of selected anthraquinones and anthraquinone derivatives. , 1991, Antiviral research.

[9]  D. Meruelo,et al.  A method for the quantitation of hypericin, an antiviral agent, in biological fluids by high-performance liquid chromatography. , 1991, Analytical biochemistry.

[10]  S. Carpenter,et al.  PHOTOSENSITIZATION IS REQUIRED FOR INACTIVATION OF EQUINE INFECTIOUS ANEMIA VIRUS BY HYPERICIN , 1991, Photochemistry and photobiology.

[11]  J. Hudson,et al.  Antiviral activities of hypericin. , 1991, Antiviral research.

[12]  G. Sheldrick.  Phase annealing in SHELX-90: direct methods for larger structures , 1990 .

[13]  R. Schinazi,et al.  Anthraquinones as a new class of antiviral agents against human immunodeficiency virus. , 1990, Antiviral research.

[14]  D. Häder,et al.  PHOTOTACTIC ORIENTATION BY THE CILIATE, STENTOR COERULEUS , 1980 .

[15]  M. Blumer.  ORGANIC PIGMENTS: THEIR LONG-TERM FATE. , 1965, Science.