1
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Reinvestigation on Photoluminescence of 7-Hydroxyflavone in aqueous medium: Proficient fluorescence enhancement. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2022.114014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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2
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Das S, Mukherjee S, Chakrabarty S, Chattopadhyay N. Hydroxyl Group-Directed Solvation of Excited-State Intramolecular Proton Transfer Probes in Water: A Demonstration from the Fluorescence Anisotropy of Hydroxyflavones. J Phys Chem A 2021; 125:57-64. [PMID: 33166155 DOI: 10.1021/acs.jpca.0c08023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Formation of a probe-solvent network resulting in unusually high fluorescence anisotropy (FA) of an excited-state intramolecular proton transfer (ESIPT) probe, 3-hydroxyflavone (3HF), in water prompted us to explore the solvation patterns on its 7-hydroxy (7HF) and 6-hydroxy (6HF) positional analogues. In the present study, it was observed that 7HF exhibits a lower FA than 3HF does in water, implying that the volume of the 7HF-water cluster is less than that of the 3HF-water cluster. Experimental and computational results led us to propose that 7HF forms its water cluster at the molecular periphery in contrast to the projected-out structure in case of the 3HF-water cluster. Density functional theory (DFT)-based quantum chemical calculations provide an approach for the differential solvation patterns of 3HF and 7HF. 6HF, a non-ESIPT probe, exhibits very low FA in water compared with both 3HF and 7HF. This study demonstrates that proper positioning of the hydroxyl group and its participation in the extended π-conjugation within the molecule dictate the formation of the solvated cluster endorsing directed solvation.
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Affiliation(s)
- Sinjan Das
- Department of Chemistry, Jadavpur University, Kolkata 700 032, India
| | - Shounak Mukherjee
- Department of Chemical, Biological & Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata 700 106, India
| | - Suman Chakrabarty
- Department of Chemical, Biological & Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata 700 106, India
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3
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Serdiuk IE, Roshal AD. 7-Hydroxyflavone Revisited. 2. Substitution Effect on Spectral and Acid–Base Properties in the Ground and Excited States. J Phys Chem A 2015; 119:12672-85. [DOI: 10.1021/acs.jpca.5b09185] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Illia E. Serdiuk
- Department
of Chemistry, University of Gdańsk, Gdańsk, 80-308 Poland
- Institute
of Chemistry, V. N. Karazin Kharkiv National University, Kharkiv, 61022 Ukraine
| | - Alexander D. Roshal
- Institute
of Chemistry, V. N. Karazin Kharkiv National University, Kharkiv, 61022 Ukraine
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4
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Serdiuk IE, Varenikov AS, Roshal AD. 7-Hydroxyflavone Revisited: Spectral, Acid–Base Properties, and Interplay of the Protolytic Forms in the Ground and Excited States. J Phys Chem A 2014; 118:3068-80. [DOI: 10.1021/jp412334x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Illia E. Serdiuk
- Institute
of Chemistry, Kharkiv V.N. Karazin National University, Svoboda 4, 61077 Kharkiv, Ukraine
- Faculty
of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-952 Gdańsk, Poland
| | - Andrii S. Varenikov
- Institute
of Chemistry, Kharkiv V.N. Karazin National University, Svoboda 4, 61077 Kharkiv, Ukraine
| | - Alexander D. Roshal
- Institute
of Chemistry, Kharkiv V.N. Karazin National University, Svoboda 4, 61077 Kharkiv, Ukraine
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5
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Simultaneous quantitation of 5- and 7-hydroxyflavone antioxidants and their binding constants with BSA using dual chiral capillary electrophoresis (dCCE) and HPLC with fluorescent detection. Talanta 2014; 119:417-24. [DOI: 10.1016/j.talanta.2013.11.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 11/06/2013] [Accepted: 11/08/2013] [Indexed: 12/27/2022]
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6
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Chaudhuri S, Pahari B, Sengupta PK. Ground and excited state proton transfer and antioxidant activity of 7-hydroxyflavone in model membranes: absorption and fluorescence spectroscopic studies. Biophys Chem 2008; 139:29-36. [PMID: 18977065 DOI: 10.1016/j.bpc.2008.09.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Revised: 09/26/2008] [Accepted: 09/29/2008] [Indexed: 11/29/2022]
Abstract
Steady state and time resolved fluorescence spectroscopy have been used to probe microenvironments of the therapeutically active intrinsically fluorescent flavonoid, 7-hydroxyflavone (7-HF), in model membranes consisting of multilamellar phosphatidylcholine liposomes. Additionally, the antioxidant effects of 7-HF against lipid peroxidation have been evaluated using spectrophotometric assay. Large Stokes shifted emissions with distinct spectroscopic signatures, are observed from the excited state proton transfer (ESPT) tautomer (which is generated by a solvent mediated mechanism) and the ground state anion of 7-HF. The neutral (7-HFN) and anionic (7-HFA) species' appear to be located in the non-polar acyl chain and the polar head group regions of the lipid vesicles respectively. The partition coefficients of 7-HFN and 7-HFA in these vesicles have also been estimated using their intrinsic fluorescence. Anisotropy (r) versus temperature (T) measurements reveal the utility of the tautomer fluorescence anisotropy as a sensitive parameter for exploring structural changes in the membranes. Fluorescence decay kinetics studies indicate heterogeneity in the microenvironments of both 7-HFN and 7-HFA. Furthermore, we demonstrate that lipid peroxidation of the model membranes is partially arrested upon 7-HF binding, suggesting its potential usefulness as an inhibitor of peroxidative damage of cell membranes.
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Affiliation(s)
- Sudip Chaudhuri
- Biophysics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064, India
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7
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Lvovskaya MI, Roshal AD, Doroshenko AO, Kyrychenko AV, Khilya VP. Fluorescence behavior of chromones containing several protolytic centers 3-Thiazolylchromones: Emission band assignment and pH dependent effects. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2006; 65:397-405. [PMID: 16533617 DOI: 10.1016/j.saa.2005.11.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Revised: 11/25/2005] [Accepted: 11/25/2005] [Indexed: 05/07/2023]
Abstract
Fluorescence properties of 3-thiazolylchromones (TC) were studied in the wide H(0)/pH range -10 to 12. It was found that the number of the excited TC protolytic forms exceeds their quantity in the ground state. The formation of the new emitting species was explained as the result of the dramatic changes in the acid-base characteristics of three protolytic centers of TC molecules under the electronic excitation. The quantum chemical evaluation of the relative thermodynamic stability of all the possible excited TC acid-base forms aiming to find out, which of them should be the most energetically favorable, was made. The assignment of the experimentally observed emission bands to the above mentioned acid-base forms of 3-thiazolylchromones was carried out. The pH/H(0) ranges, where all of the detected protolytic forms could be observed, were determined. The dissociation and protonation constants of 3-thiazolylchromones in the ground and excited states were estimated. The most probable mechanism of the excited TC cation-tautomer formation was discussed.
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Affiliation(s)
- M I Lvovskaya
- Research Institute of Chemistry, Kharkov V.N. Karazin National University, Svobody sq., 4, Kharkov 61077, Ukraine
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8
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Ma C, Zuo P, Kwok WM, Chan WS, Kan JTW, Toy PH, Phillips DL. Time-Resolved Resonance Raman Study of the Triplet States of p-Hydroxyacetophenone and the p-Hydroxyphenacyl Diethyl Phosphate Phototrigger Compound. J Org Chem 2004; 69:6641-57. [PMID: 15387586 DOI: 10.1021/jo049331a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pico- and nanosecond time-resolved resonance Raman (TR3) spectroscopy have been utilized to study the dynamics and structure of p-hydroxyacetophenone (HA) and the p-hydroxyphenacyl-caged phototrigger compound p-hydroxyphenacyl diethyl phosphate (HPDP) in acetonitrile solution. Transient intermediates were detected and attributed to the triplet states of HA and HPDP. Nanosecond-TR3 measurements were done for two isotopically substituted HA molecules to help better assign the triplet state carbonyl C=O stretching and the ring related vibrational modes. The dynamics of formation and the spectral characteristics for the triplet states were found to be similar for the HA and HPDP. The temporal evolution at very early picosecond time scale indicates there is rapid intersystem crossing (ISC) conversion and subsequent relaxation of the excess energy of the initially produced energetic triplet state. B3LYP/6-311G** density functional theory (DFT) calculations were done to determine the structures and vibrational frequencies for both the triplet and ground states of HA and HPDP. The calculated spectra reproduce the experimental spectra and the observed isotopic shifts reasonably well and were used to make tentative assignments to all the experimentally observed features. The triplet states were found to have extensive conjugated pipi* nature with a single-bond-like carbonyl CO bond. We briefly compare the triplet structure and formation dynamics of HA and HPDP as well as the conformational changes upon going from the ground state to the triplet state. We discuss our present results in relation to the initial pathway for the p-hydroxyphenacyl photodeprotection process. We also compare and discuss the properties of the HA pipi* triplet state relative to the published results of other aromatic carbonyl compounds.
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Affiliation(s)
- Chensheng Ma
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S.A.R., P. R. China
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9
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Ma C, Chan WS, Kwok WM, Zuo P, Phillips DL. Time-Resolved Resonance Raman Study of the Triplet State of the p-Hydroxyphenacyl Acetate Model Phototrigger Compound. J Phys Chem B 2004. [DOI: 10.1021/jp0376020] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chensheng Ma
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, People's Republic of China
| | - Wing Sum Chan
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, People's Republic of China
| | - Wai Ming Kwok
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, People's Republic of China
| | - Peng Zuo
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, People's Republic of China
| | - David Lee Phillips
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, People's Republic of China
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10
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Tommasini S, Calabrò ML, Donato P, Raneri D, Guglielmo G, Ficarra P, Ficarra R. Comparative photodegradation studies on 3-hydroxyflavone: influence of different media, pH and light sources. J Pharm Biomed Anal 2004; 35:389-97. [PMID: 15063471 DOI: 10.1016/s0731-7085(03)00586-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2003] [Revised: 10/14/2003] [Accepted: 10/14/2003] [Indexed: 11/28/2022]
Abstract
3-Hydroxyflavone (3-OH-F) photochemistry in solution has been rationalized in terms of an excited state intramolecular proton transfer (ESIPT), which involves the free 3-hydroxy group interacting with the ortho-carbonyl. This photo-rearrangement occurs rapidly and is strongly influenced by the physico-chemical properties of the solvent, which plays an essential role in determining whether a photo-oxidation or a photo-induced molecular rearrangement takes place. 3-OH-F photoreactivity has been deeply investigated and the related mechanisms elucidated, as affected by various solvents, pH values and irradiation wavelengths, leading to different photodegradation rates and pathways. Moreover, the influence of molecular encapsulation upon alpha- and beta-cyclodextrins (alpha- and beta-CyD) on the molecule photoreactivity has been examined, as a potential tool for increasing molecule photostability as well as minimizing photoinduced toxic effects on biosubstrates.
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Affiliation(s)
- S Tommasini
- Dipartimento Farmaco-Chimico, Facoltà di Farmacia, Università di Messina, Viale Annunziata, 98168 Messina, Italy
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11
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Calabrò ML, Tommasini S, Raneri D, Donato P, Ficarra P, Ficarra R. Selective reversed-phase liquid chromatography method for the kinetic investigation of 3-hydroxyflavone photostability. J Chromatogr B Analyt Technol Biomed Life Sci 2004; 800:245-51. [PMID: 14698261 DOI: 10.1016/j.jchromb.2003.10.019] [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: 11/30/2022]
Abstract
This paper reports a fast and accurate RP-HPLC chromatographic method for the simultaneous determination of 3-hydroxyflavone (3-OH F) and its photodegradation products. Solutions (5 x 10(-5) M) in acetonitrile (ACN) of the molecule were subjected to forced degradation by exposure to artificial UV-A light source (black-light, lambda(max) 354 nm) and the changes appearing in chromatograms were monitored at selected irradiation times. A multistep gradient was optimised to achieve complete elution of all photoproducts in the shortest analysis time. UV spectra recorded by the diode array detector system (285 and 340 nm) clearly showed the structural changes in the new species formed, with respect to the parent compound. The analytical method was subjected to a validation procedure in which linearity and range, as well as specificity, precision and accuracy were determined according to ICH guidelines. Quantitative evaluation of the photochemical process was performed on the basis of the calculated kinetic parameters: photodegradation rate constant k, half-life time t(0.5), time degradation of 10% of the drug t(0.1).
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Affiliation(s)
- M L Calabrò
- Pharmaco-Chemical Department, Faculty of Pharmacy, University of Messina, Viale Annunziata, 98168 Messina, Italy
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12
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Kumar S, Jain SK, Sharma N, Rastogi RC. Intramolecular excited-state proton-transfer studies on flavones in different environments. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2001; 57:299-308. [PMID: 11206564 DOI: 10.1016/s1386-1425(00)00374-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The absorption and fluorescence spectra of some biologically active flavones have been studied as a function of the acidity (pH/H0) of the solution. Dissociation constants have been determined for the ground and first excited singlet states. The results are compared with those obtained from Forster-Weller calculations. The acidity constants obtained by fluorimetric titration method are in complete agreement (in most of the systems) with ground state data indicating a excited state deactivation prior to prototropic equilibration. Compared to umbelliferones, flavones are only weakly fluorescent in alkaline solution. This behaviour is explained by the small energy difference between the singlet excited state and triplet excited state giving rise to more efficient intersystem crossing. Most of the flavones studied here undergo adiabatic photodissociation in the singlet excited state indicating the formation of an exciplex or a phototautomer.
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Affiliation(s)
- S Kumar
- Department of Chemistry, University of Delhi, India
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13
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Kumar S, Jain SK, Rastogi RC. An experimental and theoretical study of excited-state dipole moments of some flavones using an efficient solvatochromic method based on the solvent polarity parameter, E(N)(T). SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2001; 57:291-298. [PMID: 11206563 DOI: 10.1016/s1386-1425(00)00372-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The electronic absorption and fluorescence spectra of some biologically active natural flavones have been recorded at room temperature (298 K) in solvents of different polarities. The effects of the solvents upon the spectral properties are discussed. Difference in fluorescence intensity of flavones has been explained on the basis of intersystem crossing and degree of non-planarity calculated theoretically using Austin Model 1 (AM1) method. Excited-state dipole moments have been determined using the solvatochromic method based on the microscopic solvent polarity parameter, E(N)(T). A reasonable agreement has been observed between experimental and AM1 calculated dipole moment changes. Our results are found to be quite reliable in view of the fact that the correlation of the solvatochromic Stokes shifts with microscopic solvent polarity parameter, E(N)(T) is superior to that obtained using bulk solvent polarity functions for all the systems studied here.
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Affiliation(s)
- S Kumar
- Department of Chemistry, University of Delhi, India
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14
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Brousmiche DW, Wan P. Excited state (formal) intramolecular proton transfer (ESIPT) in p-hydroxyphenyl ketones mediated by water. J Photochem Photobiol A Chem 2000. [DOI: 10.1016/s1010-6030(99)00219-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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15
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Zhang K, Corrie JET, Munasinghe VRN, Wan P. Mechanism of Photosolvolytic Rearrangement of p-Hydroxyphenacyl Esters: Evidence for Excited-State Intramolecular Proton Transfer as the Primary Photochemical Step. J Am Chem Soc 1999. [DOI: 10.1021/ja984187u] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kai Zhang
- Contribution from the Department of Chemistry, Box 3065, University of Victoria, Victoria, British Columbia, Canada V8W 3V6, and National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, U.K
| | - John E. T. Corrie
- Contribution from the Department of Chemistry, Box 3065, University of Victoria, Victoria, British Columbia, Canada V8W 3V6, and National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, U.K
| | - V. Ranjit N. Munasinghe
- Contribution from the Department of Chemistry, Box 3065, University of Victoria, Victoria, British Columbia, Canada V8W 3V6, and National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, U.K
| | - Peter Wan
- Contribution from the Department of Chemistry, Box 3065, University of Victoria, Victoria, British Columbia, Canada V8W 3V6, and National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, U.K
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16
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Fischer M, Wan P. Nonlinear Solvent Water Effects in the Excited-State (Formal) Intramolecular Proton Transfer (ESIPT) in m-Hydroxy-1,1-diaryl Alkenes: Efficient Formation of m-Quinone Methides1. J Am Chem Soc 1999. [DOI: 10.1021/ja983557b] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- Maike Fischer
- Contribution from the Department of Chemistry, Box 3065, University of Victoria, Victoria, British Columbia, Canada V8W 3V6
| | - Peter Wan
- Contribution from the Department of Chemistry, Box 3065, University of Victoria, Victoria, British Columbia, Canada V8W 3V6
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17
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Kurono M, Mitsuhashi C, Kohtani S, Itoh M. Formation and Photodissociation of a Jet-Cooled Intramolecular Exciplex in the Bichromophoric EDA System: Multiconformations and Deuteration Effect. J Phys Chem A 1997. [DOI: 10.1021/jp9640639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Makoto Kurono
- Department of Physical and Chemical Biodynamics, Faculty of Pharmaceutical Sciences, Kanazawa University, Takara-machi, Kanazawa 920, Japan
| | - Chiaki Mitsuhashi
- Department of Physical and Chemical Biodynamics, Faculty of Pharmaceutical Sciences, Kanazawa University, Takara-machi, Kanazawa 920, Japan
| | - Shigeru Kohtani
- Department of Physical and Chemical Biodynamics, Faculty of Pharmaceutical Sciences, Kanazawa University, Takara-machi, Kanazawa 920, Japan
| | - Michiya Itoh
- Department of Physical and Chemical Biodynamics, Faculty of Pharmaceutical Sciences, Kanazawa University, Takara-machi, Kanazawa 920, Japan
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18
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Kurono M, Mitsuhashi C, Kohtani S, Itoh M. Photodissociation of Jet-Cooled Intramolecular Exciplex in 1-(9-Anthryl)-3-(p-(N,N-dimethylamino)phenyl)propane: Formation of Excited-State Anthryl and Deuteration Effect. J Phys Chem A 1997. [DOI: 10.1021/jp961795s] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Makoto Kurono
- Department of Physical and Chemical Biodynamics, Graduate School and Faculty of Pharmaceutical Sciences, Kanazawa University, Takara-machi, Kanazawa 920, Japan
| | - Chiaki Mitsuhashi
- Department of Physical and Chemical Biodynamics, Graduate School and Faculty of Pharmaceutical Sciences, Kanazawa University, Takara-machi, Kanazawa 920, Japan
| | - Shigeru Kohtani
- Department of Physical and Chemical Biodynamics, Graduate School and Faculty of Pharmaceutical Sciences, Kanazawa University, Takara-machi, Kanazawa 920, Japan
| | - Michiya Itoh
- Department of Physical and Chemical Biodynamics, Graduate School and Faculty of Pharmaceutical Sciences, Kanazawa University, Takara-machi, Kanazawa 920, Japan
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Influence of methoxy substitution on flavonoid photophysics: a steady state and laser flash photolysis study. J Photochem Photobiol A Chem 1996. [DOI: 10.1016/s1010-6030(96)04422-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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20
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Sarkar M, Guha Ray J, Sengupta PK. Luminescence behaviour of 7-hydroxyflavone in aerosol OT reverse micelles: excited-state proton transfer and red-edge excitation effects. J Photochem Photobiol A Chem 1996. [DOI: 10.1016/1010-6030(95)04251-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Kohtani S, Murata M, Itoh M. Resonance energy transfer from the excited singlet state of dye molecules to a stable free radical. Chem Phys Lett 1995. [DOI: 10.1016/0009-2614(95)01210-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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22
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Tsukahara K, Sawai N, Hamada S, Nakazawa T, Nakagaki R. Kinetics and Mechanisms of Photoinduced Reduction of Methylviologen byN-Alkyltetraphenylporphyrinatozinc(II) in Methanol. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1995. [DOI: 10.1246/bcsj.68.1947] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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