1
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Kumar V. 2-Naphthoic acid prototropism within ionic liquid based media. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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2
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Mirochnik AG, Yu A, Beloliptsev, Fedorenko EV. Dual Luminescence of 1‐(9‐Anthryl)Butane‐1,3‐dione. ChemistrySelect 2020. [DOI: 10.1002/slct.201904327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Anatolii G. Mirochnik
- Institute of Chemistry Far Eastern Branch of the Russian Academy of Sciences 159, Prosp. 100-letiya Vladivostoka Vladivostok 690022 Russian Federation
| | - Anton Yu
- Institute of Chemistry Far Eastern Branch of the Russian Academy of Sciences 159, Prosp. 100-letiya Vladivostoka Vladivostok 690022 Russian Federation
| | - Beloliptsev
- Institute of Chemistry Far Eastern Branch of the Russian Academy of Sciences 159, Prosp. 100-letiya Vladivostoka Vladivostok 690022 Russian Federation
| | - Elena V. Fedorenko
- Institute of Chemistry Far Eastern Branch of the Russian Academy of Sciences 159, Prosp. 100-letiya Vladivostoka Vladivostok 690022 Russian Federation
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3
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Han C, Yang W, Yang H, Xue X. Enhanced photochemical conversion of NO 2 to HONO on humic acids in the presence of benzophenone. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 231:979-986. [PMID: 28888942 DOI: 10.1016/j.envpol.2017.08.107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/14/2017] [Accepted: 08/30/2017] [Indexed: 06/07/2023]
Abstract
The photochemical conversion of NO2 to HONO on humic acids (HA) in the presence of benzophenone (BP) was investigated using a flow tube reactor coupled to a NOx analyzer at ambient pressure. BP significantly enhanced the reduction of NO2 to HONO on HA under simulated sunlight, as shown by the increase of NO2 uptake coefficient (γ) and HONO yield with the mass ratio of BP to HA. The γ and HONO yield on the mixtures of HA and BP obviously depended on the environmental conditions. Both γ and HONO yield increased with the increase of irradiation intensity and temperature, whereas they decreased with pH. The γ exhibited a negative dependence on the NO2 concentration, which had slight influences on the HONO yield. There were maximum values for the γ and HONO yield at relative humidity (RH) of 22%. Finally, atmospheric implications about the photochemical reaction of NO2 and HA in the presence of photosensitive species were discussed.
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Affiliation(s)
- Chong Han
- School of Metallurgy, Northeastern University, Shenyang, 110819, China.
| | - Wangjin Yang
- School of Metallurgy, Northeastern University, Shenyang, 110819, China
| | - He Yang
- School of Metallurgy, Northeastern University, Shenyang, 110819, China
| | - Xiangxin Xue
- School of Metallurgy, Northeastern University, Shenyang, 110819, China
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4
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Scheiner S. Monitoring the Charge Distribution during Proton and Sodium Ion Conduction along Chains of Water Molecules and Protein Residues. Isr J Chem 2016. [DOI: 10.1002/ijch.201600062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry; Utah State University; Logan UT 84322-0300 USA
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Kumar V, Pandey A, Pandey S. Proton-Transfer Reactions of Acridine in Water-Containing Ionic-Liquid-Rich Mixtures. Chemphyschem 2013; 14:3944-52. [DOI: 10.1002/cphc.201300817] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 09/25/2013] [Indexed: 11/11/2022]
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6
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Spies C, Finkler B, Acar N, Jung G. Solvatochromism of pyranine-derived photoacids. Phys Chem Chem Phys 2013; 15:19893-905. [DOI: 10.1039/c3cp53082e] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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7
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Kumar V, Pandey S. Selective Quenching of 2-Naphtholate Fluorescence by Imidazolium Ionic Liquids. J Phys Chem B 2012; 116:12030-7. [DOI: 10.1021/jp3080817] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vinod Kumar
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Siddharth Pandey
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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Zhao X, Huang CZ. A molecular logic gate for the highly selective recognition of pyrophosphate with a hypocrellin A-Zn(II) complex. Analyst 2010; 135:2853-7. [PMID: 20877861 DOI: 10.1039/c0an00431f] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pyrophosphate (PPi) participates in many biological and chemical processes such as energy transduction so that investigations on its role and detection have become very significant. In this contribution, we have developed a molecular logic gate for the recognition of PPi with a fluorescent hypocrellin A-zinc(II) complex (HA-Zn(2+)), and the outputs of which correspond to the fluorescence emission ratio at 604 nm and wavelength shift relative to 629 nm. The emission at 604 nm is the intrinsic fluorescence of HA, which can be effectively quenched by Zn(2+) with a new emission at 629 nm owing to the formation of the HA-Zn(2+) complex. It was found, however, that the new emission at 629 nm is highly selectively quenched with the addition of PPi, recovering the emission at 604 nm, and the recovery ratio is linearly correlated with PPi in the range of 1.8 × 10(-5) mol L(-1) to 2.4 × 10(-4) mol L(-1). ATP, UTP, CTP, GTP, GDP and GMP cannot demonstrate the same spectral actions as PPi. Since the inputs of PPi and the phosphate anions obtain different logical outputs, the designed logic gates have good selectivity and can distinguish PPi from the other anions.
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Affiliation(s)
- Xijuan Zhao
- Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, College of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, P. R. China
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Sen Mojumdar S, Mondal T, Das AK, Dey S, Bhattacharyya K. Ultrafast and ultraslow proton transfer of pyranine in an ionic liquid microemulsion. J Chem Phys 2010; 132:194505. [DOI: 10.1063/1.3428669] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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10
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Liang YH, Yi PG, Peng HL. Theoretical study of structure, energetic and intramolecular hydrogen transfer of hypocrellin A. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.09.074] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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11
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Mallick A, Purkayastha P, Chattopadhyay N. Photoprocesses of excited molecules in confined liquid environments: An overview. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2007. [DOI: 10.1016/j.jphotochemrev.2007.06.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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12
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Lobban CS, Hallam SJ, Mukherjee P, Petrich JW. Photophysics and Multifunctionality of Hypericin-Like Pigments in Heterotrich Ciliates: A Phylogenetic Perspective. Photochem Photobiol 2007; 83:1074-94. [PMID: 17880503 DOI: 10.1111/j.1751-1097.2007.00191.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this paper, we review the literature and present some new data to examine the occurrence and photophysics of the diverse hypericin-like chromophores in heterotrichs, the photoresponses of the cells, the various roles of the pigments and the taxa that might be studied to advance our understanding of these pigments. Hypericin-like chromophores are known chemically and spectrally so far only from the stentorids and Fabrea, the latter now seen to be sister to stentorids in the phylogenetic tree. For three hypericin-like pigments, the structures are known but these probably do not account for all the colors seen in stentorids. At least eight physiological groups of Stentor exist depending on pigment color and presence/absence of zoochlorellae, and some species can be bleached, leading to many opportunities for comparison of pigment chemistry and cell behavior. Several different responses to light are exhibited among heterotrichs, sometimes by the same cell; in particular, cells with algal symbionts are photophilic in contrast to the well-studied sciaphilous (shade-loving) species. Hypericin-like pigments are involved in some well-known photophobic reactions but other pigments (rhodopsin and flavins) are also involved in photoresponses in heterotrichs and other protists. The best characterized role of hypericin-like pigments in heterotrichs is in photoresponses and they have at least twice evolved a role as photoreceptors. However, hypericin and hypericin-like pigments in diverse organisms more commonly serve as predator defense and the pigments are multifunctional in heterotrichs. A direct role for the pigments in UV protection is possible but evidence is equivocal. New observations are presented on a folliculinid from deep water, including physical characterization of its hypericin-like pigment and its phylogenetic position based on SSU rRNA sequences. The photophysics of hypericin and hypericin-like pigments is reviewed. Particular attention is given to how their excited-state properties are modified by the environment. Dramatic changes in excited-state behavior are observed as hypericin is moved from the homogeneous environment of organic solvents to the much more structured surroundings provided by the complexes it forms with proteins. Among these complexes, it is useful to consider the differences between environments where hypericin is not found naturally and those where it is, notably, for example, in heterotrichs. It is clear that interaction with a protein modifies the photophysics of hypericin and understanding the molecular basis of this interaction is one of the outstanding problems in elucidating the function of hypericin and hypericin-like chromophores.
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Sanders L, Halder M, Xiao TL, Ding J, Armstrong DW, Petrich JW. The Separation of Hypericin's Enantiomers and Their Photophysics in Chiral Environments¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2005.tb01539.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Chowdhury PK, Ashby KD, Datta A, Petrich JW. Effect of pH on the Fluorescence and Absorption Spectra of Hypericin in Reverse Micelles¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2000)0720612eopotf2.0.co2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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15
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Showalter BM, Datta A, Chowdhury PK, Park J, Bandyopadhyay P, Choudhury PK, Kesavan S, Zeng Y, Kraus GA, Gordon MS, Toscano JP, Petrich JW. Identification of a Vibrational Frequency Corresponding to H-atom Translocation in Hypericin¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2001)0740157ioavfc2.0.co2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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16
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Freeman D, Konstantinovskii L, Mazur Y. The Structure of Hypericin in Solution. Searching for Hypericin's 1,6 Tautomer¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2001)0740206tsohis2.0.co2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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17
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Park J, Datta A, Chowdhury PK, Petrich JW. Is the Excited-State H-atom Transfer in Hypericin Concerted?¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2001)0730105itesha2.0.co2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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18
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Zhang HY, Liu W, Liu WZ, Xie JL. Photosensitization of Hypomycin B-A Novel Perylenequinonoid Pigment with Only One Intramolecular Hydrogen Bond¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2001)0740191pohban2.0.co2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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19
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Xu S, Zhang X, Chen S, Zhang M, Shen T. The Fluorescence Properties of Hypocrellin B and its Amino-substituted Derivative: Photinduced Intramolecular Proton Transfer and Photoinduced Intramolecular Electron Transfer¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2004.tb00057.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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20
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Krishnamoorthy G, Webb SP, Nguyen T, Chowdhury PK, Halder M, Wills NJ, Carpenter S, Kraus GA, Gordon MS, Petrich JW. Synthesis of Hydroxy and Methoxy Perylene Quinones, Their Spectroscopic and Computational Characterization, and Their Antiviral Activity¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2005.tb01464.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Li H, Wang Y, Yan Z, Feng H, Hu Y. Proton transfer of magnolol in ground and excited states. J Photochem Photobiol A Chem 2007. [DOI: 10.1016/j.jphotochem.2006.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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22
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Halder M, Chowdhury PK, Das R, Mukherjee P, Atkins WM, Petrich JW. Interaction of Glutathione S-Transferase with Hypericin: A Photophysical Study. J Phys Chem B 2005; 109:19484-9. [PMID: 16853517 DOI: 10.1021/jp051645u] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The photophysics of hypericin have been studied in its complex with two different isoforms, A1-1 and P1-1, of the protein glutathione S-transferase (GST). One molecule of hypericin binds to each of the two GST subunits. Comparisons are made with our previous results for the hypericin/human serum albumin complex (Photochem. Photobiol. 1999, 69, 633-645). Hypericin binds with high affinity to the GSTs: 0.65 microM for the A1-1 isoform and 0.51 microM for the P1-1 isoform (Biochemistry 2004, 43, 12761-12769). The photophysics and activity of hypericin are strongly modulated by the binding protein. Intramolecular hydrogen-atom transfer is suppressed in both cases. Most importantly, while there is significant singlet oxygen generation from hypericin bound to GST A1-1, binding to GST P1-1 suppresses singlet oxygen generation to almost negligible levels. The data are rationalized in terms of a simple model in which the hypericin photophysics depends entirely upon the decay of the triplet state by two competing processes, quenching by oxygen to yield singlet oxygen and ionization, the latter of these two are proposed to be modulated by A1-1 and P1-1.
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Affiliation(s)
- M Halder
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
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Plaza P, Mahet M, Tchaikovskaya ON, Martin MM. Excitation energy effect on the early photophysics of hypericin in solution. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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24
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Chen D, Shen L. Theoretical study on the photophysical and photochemical characteristics of aluminum ion-complexed perylenequinone. J Photochem Photobiol A Chem 2005. [DOI: 10.1016/j.jphotochem.2004.10.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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25
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Parra RD, Dukarevich I. A comparative ab initio study of intramolecular proton transfer in model alpha-hydroxyalkoxides. J Chem Phys 2005; 122:124316. [PMID: 15836387 DOI: 10.1063/1.1869474] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
A comparative ab initio study was performed on the intramolecular proton-transfer reaction that occurs in alpha-hydroxyethanoxy, alpha-hydroxyphenoxide, and alpha-hydroxyethenoxy anions. The intramolecular proton transfer occurs in a five-member atom arrangement, between two oxygen atoms separated by a carbon-carbon bond. The chosen systems serve as models for alpha-hydroxyalkoxide molecules where the carbon-carbon bond varies from a single bond (the glycolate anion or alpha-hydroxyethanoxide anion) to a part of an aromatic ring (the alpha-hydroxyphenoxide anion), and finally to a double bond (the alpha-hydroxyethenoxide anion). Particular attention was given to the evolution along the intrinsic reaction coordinate of such properties as energies, relevant structural parameters, Mulliken charges, dipole moments, and 1H-NMR chemical shifts to reveal the similarities and differences for the proton transfer in the model systems.
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Affiliation(s)
- Rubén D Parra
- Department of Chemistry, DePaul University, Chicago, Illinois 60614, USA.
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Chen DZ, Wang DP, Kong DX, Zhang X. Quantum study on photophysical and photochemical process of a new photosensitizer: hypomycin B. J Photochem Photobiol A Chem 2005. [DOI: 10.1016/j.jphotochem.2004.07.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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27
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Sanders L, Halder M, Xiao TL, Ding J, Armstrong DW, Petrich JW. The Separation of Hypericin's Enantiomers and Their Photophysics in Chiral Environments¶. Photochem Photobiol 2005. [DOI: 10.1562/2004-05-28-rn-181.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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28
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Krishnamoorthy G, Webb SP, Nguyen T, Chowdhury PK, Halder M, Wills NJ, Carpenter S, Kraus GA, Gordon MS, Petrich JW. Synthesis of Hydroxy and Methoxy Perylene Quinones, Their Spectroscopic and Computational Characterization, and Their Antiviral Activity¶. Photochem Photobiol 2005. [DOI: 10.1562/2004-11-23-ra-378r1.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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29
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Wang DP, Chen SG, Chen DZ. Theoretical studies of conjugate and substituent effects on the intramolecular proton transfer: an HF/CIS study. J Photochem Photobiol A Chem 2004. [DOI: 10.1016/s1010-6030(03)00382-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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30
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Xu S, Zhang X, Chen S, Zhang M, Shen T. The Fluorescence Properties of Hypocrellin B and its Amino-substituted Derivative: Photoinduced Intramolecular Proton Transfer and Photoinduced Intramolecular Electron Transfer¶. Photochem Photobiol 2004; 80:112-4. [PMID: 15339225 DOI: 10.1562/2004-03-13-rn-113.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We report on the emission spectra and emission quantum yields of a newly synthesized hypocrellin dye, 2-demethoxy-2,3-ethylenediamino hypocrellin B (EDAHB), and its parent HB in different solvents of varying polarity. Our results demonstrate that EDAHB is one of the few dyes that exhibit highly solvent polarity-dependent fluorescence in the useful region (680-730 nm). Therefore, it offers some applications in the biomedical field as a fluorescent probe molecule. The solvatochromic effect of EDAHB is proposed to be due to a distinct change in the dipole moment of the dye on excitation. A photoinduced intramolecular proton transfer and a photoinduced intramolecular electron transfer process are considered relevant for the fluorescence properties of HB and EDAHB, respectively.
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Affiliation(s)
- Shangjie Xu
- Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, People's Republic of China.
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Wang DP, Chen SG, Chen DZ. Theoretical study on the trihydroxy-anthraquinone tautomerism in the ground and excited states. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0166-1280(03)00529-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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32
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Xu S, Chen S, Zhang M, Shen T. First synthesis of methylated hypocrellin and its fluorescent excited state: a cautionary tale. J Org Chem 2003; 68:2048-50. [PMID: 12608836 DOI: 10.1021/jo026554x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Methylated hypocrellins were obtained and characterized by satisfactory 1HNMR, UV-vis, IR, and mass data, and their absorption and fluorescence emission spectra were studied. A previous report of methylated hypocrellin (J. Phys. Chem. A 1999, 103, 7949) appears to be in error.
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Affiliation(s)
- Shangjie Xu
- Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P. R. China
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Chowdhury P, Das K, Datta A, Liu WZ, Zhang HY, Petrich J. A comparison of the excited-state processes of nearly symmetrical perylene quinones: hypocrellin A and hypomycin B. J Photochem Photobiol A Chem 2002. [DOI: 10.1016/s1010-6030(02)00309-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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34
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Chen DZ, Wang DP, Zhang HY, Tang B. Theoretical study on the ground and excited state intramolecular proton transfer in perylenequinone. Chem Phys Lett 2002. [DOI: 10.1016/s0009-2614(01)01471-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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35
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Freeman D, Konstantinovskii L, Mazur Y. The structure of hypericin in solution. Searching for hypericin's 1,6 tautomer. Photochem Photobiol 2001; 74:206-10. [PMID: 11547556 DOI: 10.1562/0031-8655(2001)074<0206:tsohis>2.0.co;2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Hypericin in organic solvents displays two types of electronic spectra: one type which shows a distinct solvatochromic effect, the stable form, and the other, the unstable form, which lacks this property. The latter type is formed in dry nonprotic solvents (e.g. tetrahydrofuran, EtOAc) and can be converted to the stable form on addition of protic solvents. In order to establish the tautomeric structure of the unstable form we applied conventional nuclear magnetic resonance techniques as well as two-dimensional gradient-enhanced heteronuclear multiple-quantum correlation, gradient-enhanced ROESY and one-dimensional nuclear Overhauser effect difference experiments. All these techniques pointed to the fact that the unstable form has the 7,14-diketo tautomeric structure, like the stable form, and not the 1,6-diketo structure. Electronic spectroscopy indicated that the unstable form has acidic properties and therefore possesses two free OH groups at C3 and C4 at the bay region of the molecule.
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Affiliation(s)
- D Freeman
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
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36
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Showalter BM, Datta A, Chowdhury PK, Park J, Bandyopadhyay P, Choudhury PK, Kesavan S, Zeng Y, Kraus GA, Gordon MS, Toscano JP, Petrich JW. Identification of a vibrational frequency corresponding to H-atom translocation in hypericin. Photochem Photobiol 2001; 74:157-63. [PMID: 11547549 DOI: 10.1562/0031-8655(2001)074<0157:ioavfc>2.0.co;2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Using time-resolved infrared spectroscopy, ab initio quantum mechanical calculations and synthetic organic chemistry a region in the infrared spectrum of triplet hypericin has been found between 1400 and 1500 cm-1 corresponding to the translocation of the hydrogen atom between the enol and the keto oxygens, O...H...O. This result is discussed in the context of the photophysics of hypericin and of eventual measurements to observe directly the excited-state H-atom transfer.
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Affiliation(s)
- B M Showalter
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, USA
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Zhang HY, Liu W, Liu WZ, Xie JL. Photosensitization of hypomycin B--a novel perylenequinonoid pigment with only one intramolecular hydrogen bond. Photochem Photobiol 2001; 74:191-5. [PMID: 11547553 DOI: 10.1562/0031-8655(2001)074<0191:pohban>2.0.co;2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Electron spin resonance technique and spin-trapping methods were used to determine the photoproduction of 1O2 and O2.- by hypomycin B (HMB), a novel perylenequinonoid pigment (PQP) possessing only one hydroxyl group. It was found that the yields of 1O2 and O2.- for HMB were comparable to those for hypocrellin A, a typical natural PQP with good photosensitivity. In addition, the absorption and fluorescence spectra for HMB were investigated. The pKa values in the ground and excited states of HMB were determined to be 8.94 and 5.54, respectively. Thus, the photodynamic mechanisms of HMB may involve not only the photogeneration of 1O2 and O2.- but also the light-induced acidification. Consequently, HMB is proposed to be a good photodynamic therapeutic agent.
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Affiliation(s)
- H Y Zhang
- Laboratory for Computational Biology, Shandong Provincial Research Center for Bioinformatic Engineering and Technique, Zibo University, Zibo, People's Republic of China.
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Abstract
The excited-state intramolecular H-atom transfer of hypericin (Hyp) was investigated as a function of pH in monodispersed reverse micelles formed by sodium bis(2-ethylhexyl)sulfosuccinate/heptane/water and in complexes with Tb3+ under conditions in which one of the two carbonyl groups of Hyp is incapable of accepting a hydrogen atom. The results of pump-probe transient absorption experiments provide no evidence for a concerted H-atom transfer mechanism.
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Affiliation(s)
- J Park
- Department of Chemistry, Iowa State University, Ames 50011, USA
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Chowdhury PK, Ashby KD, Datta A, Petrich JW. Effect of pH on the fluorescence and absorption spectra of hypericin in reverse micelles. Photochem Photobiol 2000; 72:612-8. [PMID: 11107845 DOI: 10.1562/0031-8655(2000)072<0612:eopotf>2.0.co;2] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The well-characterized, monodispersed nature of reverse micelles formed by sodium bis(2-ethylhexyl)sulfosuccinate/heptane and their usefulness in approximating a membrane-like environment have been exploited to investigate the effect of pH and water pool size on the photophysical properties of hypericin (Hyp). Our measurements reveal two titratable groups of pKa approximately 1.5 and approximately 12.5. These are assigned to the HypH+/Hyp equilibrium (the deprotonation of a carbonyl group) and the Hyp-/Hyp2- equilibrium (the deprotonation of a peri hydroxyl group). The low-energy absorbance maxima of HypH+, of Hyp and Hyp- and of Hyp2- are 583, 594 and 613 nm, respectively. Neither at pH 13 nor at 1 M HCl is the system entirely in the Hyp2- or the HypH+ forms. Ours is the first study of Hyp in reverse micelles as well as the first time-resolved study of Hyp as a function of pH.
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Affiliation(s)
- P K Chowdhury
- Department of Chemistry, Iowa State University, Ames 50011, USA
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Datta A, Smirnov AV, Wen J, Chumanov G, Petrich JW. Multidimensional reaction coordinate for the excited-state H-atom transfer in perylene quinones: importance of the 7-membered ring in hypocrellins A and B. Photochem Photobiol 2000. [PMID: 10687390 DOI: 10.1562/0031-8655(2000)0710166mrcfte2.0.co2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The excited-state intramolecular H-atom transfer reactions of hypocrellins B and A are compared by using time-resolved absorption and fluorescence upconversion techniques. The hypocrellin B photophysics are well described by a simple model involving one ground-state species and excited-state forward and reverse H-atom transfer with a nonfluorescent excited state. We suggest that excited-state conformational changes are coupled to the H-atom transfer in hypocrellin B just as gauche/anti changes are coupled to the H-atom transfer in hypocrellin A.
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Affiliation(s)
- A Datta
- Department of Chemistry, Iowa State University, Ames 50011, USA
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Das K, Smirnov AV, Wen J, Miskovsky P, Petrich JW. Photophysics of Hypericin and Hypocrellin A in Complex with Subcellular Components: Interactions with Human Serum Albumin. Photochem Photobiol 1999. [DOI: 10.1111/j.1751-1097.1999.tb03339.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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