1
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Özcan E, Šímová I, Bína D, Litvín R, Polívka T. Ultrafast spectroscopy of the hydrophilic carotenoid crocin at various pH. Phys Chem Chem Phys 2024; 26:10225-10233. [PMID: 38497307 DOI: 10.1039/d4cp00665h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
This study delves into the pH-dependent effects on the excited-state behavior of crocin, a hydrophilic carotenoid with diverse functions in biological systems. Steady-state spectroscopy demonstrates notable changes in absorption and fluorescence spectra, characterized by a pH-dependent blue shift and altered resolution of vibrational bands. Transient absorption spectra further elucidate these effects, highlighting a significant blue shift in the S1-Sn peak with increasing pH. Detailed kinetic analysis shows the pH-dependent dynamics of crocin's excited states. At pH 11, a shortening of effective conjugation is observed, resulting in a prolonged S1/ICT lifetime. Conversely, at pH 9, our data suggest a more complex scenario, suggesting the presence of two distinct crocin species with different relaxation patterns. This implies structural alterations within the crocin molecule, potentially linked to the deprotonation of hydroxyl groups in crocin and/or saponification at high pH.
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Affiliation(s)
- Emrah Özcan
- Department of Physics, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic.
| | - Ivana Šímová
- Department of Physics, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic.
| | - David Bína
- Department of Chemistry, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Czech Academy of Sciences, Biology Centre, Institute of Plant Molecular Biology, Laboratory of Plant Biophysics and Biochemistry, České Budějovice, Czech Republic
| | - Radek Litvín
- Department of Chemistry, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Czech Academy of Sciences, Biology Centre, Institute of Plant Molecular Biology, Laboratory of Plant Biophysics and Biochemistry, České Budějovice, Czech Republic
| | - Tomáš Polívka
- Department of Physics, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic.
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2
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Fusi F, Romano G, Speranza G, Agati G. Photon- and Singlet-Oxygen-Induced Cis-Trans Isomerization of the Water-Soluble Carotenoid Crocin. Int J Mol Sci 2023; 24:10783. [PMID: 37445961 DOI: 10.3390/ijms241310783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/20/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
Studying the cis-trans isomerization process in crocin (CR), one of the few water-soluble carotenoids extracted from saffron, is important to better understand the physiological role of cis-carotenoids in vivo and their potential as antioxidants in therapeutic applications. For that, cis-trans isomerization of both methanol- and water-dissolved CR was induced by light or thermally generated singlet oxygen (1O2). The kinetics of molecular concentrations were monitored by both high-performance liquid chromatography (HPLC) and non-destructive spectrophotometric methods. These last made it possible to simultaneously follow the cis-trans isomerization, the possible bleaching of compounds and the amount of thermally generated 1O2. Our results were in accordance with a comprehensive model where the cis-trans isomerization occurs as relaxation from the triplet state of all-trans- or 13-cis-CR, whatever is the way to populate the CR triplet state, either by photon or 1O2 energy transfer. The process is much more (1.9 to 10-fold) efficient from cis to trans than vice versa. In H2O, a 1O2-induced bleaching effect on the starting CR was not negligible. However, the CR "flip-flop" isomerization reaction could still occur, suggesting that this process can represent an efficient mechanism for quenching of reactive oxygen species (ROS) in vivo, with a limited need of carotenoid regeneration.
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Affiliation(s)
- Franco Fusi
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Viale G. Pieraccini, 6, 50139 Florence, Italy
| | - Giovanni Romano
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Viale G. Pieraccini, 6, 50139 Florence, Italy
| | - Giovanna Speranza
- Department of Chemistry, University of Milan, Via Golgi 19, 20133 Milan, Italy
| | - Giovanni Agati
- "Nello Carrara" Institute of Applied Physics (IFAC), National Research Council (CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy
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3
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Özcan E, Kuznetsova V, Keşan G, Fuciman M, Litvín R, Polívka T. Ultrafast Excited States Dynamics of Metal Ion Complexes of the Carotenoid Astaxanthin. J Photochem Photobiol A Chem 2023. [DOI: 10.1016/j.jphotochem.2023.114737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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4
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Kosumi D, Kusumoto T, Hashimoto H. Unique ultrafast excited states dynamics of artificial short-polyene carotenoid analog 2-(all-trans-β-ionylideneetinylidene)-indan-1,3-dione. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2021.113424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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5
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Kuznetsova V, Chábera P, Litvín R, Polívka T, Fuciman M. Effect of Isomerization on Excited-State Dynamics of Carotenoid Fucoxanthin. J Phys Chem B 2017; 121:4438-4447. [DOI: 10.1021/acs.jpcb.7b02526] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Valentyna Kuznetsova
- Institute
of Physics and Biophysics, Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
| | - Pavel Chábera
- Division
of Chemical Physics, Lund University, P.O. Box 124, Lund SE-22100, Sweden
| | - Radek Litvín
- Institute
of Physics and Biophysics, Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
- Institute
of Plant Molecular Biology, Biological Centre, Czech Academy of Sciences, 37005 České Budějovice, Czech Republic
| | - Tomáš Polívka
- Institute
of Physics and Biophysics, Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
- Institute
of Plant Molecular Biology, Biological Centre, Czech Academy of Sciences, 37005 České Budějovice, Czech Republic
| | - Marcel Fuciman
- Institute
of Physics and Biophysics, Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
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6
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Kosumi D, Kajikawa T, Sakaguchi K, Katsumura S, Hashimoto H. Excited state properties of β-carotene analogs incorporating a lactone ring. Phys Chem Chem Phys 2017; 19:3000-3009. [PMID: 28079227 DOI: 10.1039/c6cp06828f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Carotenoids possessing a carbonyl group along their polyene backbone exhibit unique excited state properties due to the occurrence of intramolecular charge transfer (ICT) in the excited state. In fact, the ICT characteristics of naturally occurring carbonyl carotenoids play an essential role in the highly efficient energy transfer that proceeds in aquatic photosynthetic antenna systems. In the present study, we synthesized two short-chain polyene carotenoids incorporating a lactone ring, denoted as BL-7 and BL-8, having seven and eight conjugated double bonds (n = 7 and 8), respectively. The excited state properties of these compounds were directly compared to those of their non-carbonyl counterparts to clarify the role of the carbonyl group in the generation of ICT. The energies of the optically allowed S2 states for BL-7 and BL-8 were found to be more than 0.3 eV (2400 cm-1) below those of non-carbonyl short β-carotene homologs. Ultrafast spectroscopic data demonstrated various solvent polarity-induced effects, including the appearance of stimulated emission in the near-IR region in the case of BL-7, and significant lifetime shortening of the lowest-lying singlet S1 excited states of both BL-7 and BL-8. These results suggest that these compounds exhibit ICT characteristics.
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Affiliation(s)
- Daisuke Kosumi
- Institute of Pulsed Power Science, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto, 860-8555, Japan.
| | - Takayuki Kajikawa
- Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda, Hyogo 669-1337, Japan
| | - Kazuhiko Sakaguchi
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Shigeo Katsumura
- Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda, Hyogo 669-1337, Japan and Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Hideki Hashimoto
- Department of Applied Chemistry for Environment, Faculty of Science and Technology, Kwansei Gakuin University, Japan.
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7
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Durchan M, Keşan G, Šlouf V, Fuciman M, Staleva H, Tichý J, Litvín R, Bína D, Vácha F, Polívka T. Highly efficient energy transfer from a carbonyl carotenoid to chlorophyll a in the main light harvesting complex of Chromera velia. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1748-55. [DOI: 10.1016/j.bbabio.2014.06.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 06/01/2014] [Accepted: 06/03/2014] [Indexed: 11/26/2022]
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8
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Kosumi D, Fujii R, Sugisaki M, Oka N, Iha M, Hashimoto H. Characterization of the intramolecular transfer state of marine carotenoid fucoxanthin by femtosecond pump-probe spectroscopy. PHOTOSYNTHESIS RESEARCH 2014; 121:61-68. [PMID: 24676808 DOI: 10.1007/s11120-014-9995-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 03/06/2014] [Indexed: 06/03/2023]
Abstract
Fucoxanthin, containing a carbonyl group in conjugation with its polyene backbone, is a naturally occurring pigment in marine organisms and is essential to the photosynthetic light-harvesting function in brown alga and diatom. Fucoxanthin exhibits optical characteristics attributed to an intramolecular charge transfer (ICT) state that arises in polar environments due to the presence of the carbonyl group. In this study, we report the spectroscopic properties of fucoxanthin in methanol (polar and protic solvent) observed by femtosecond pump-probe measurements in the near-infrared region, where transient absorption associated with the optically allowed S2 (1(1)B u (+) ) state and stimulated emission from the strongly coupled S1/ICT state were observed following one-photon excitation to the S2 state. The results showed that the amplitude of the stimulated emission of the S1/ICT state increased with decreasing excitation energy, demonstrating that the fucoxanthin form associated with the lower energy of the steady-state absorption exhibits stronger ICT character.
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Affiliation(s)
- Daisuke Kosumi
- The Osaka City University Advanced Research Institute for Natural Science and Technology (OCARINA), 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan,
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9
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Kosumi D, Kajikawa T, Yano K, Okumura S, Sugisaki M, Sakaguchi K, Katsumura S, Hashimoto H. Roles of allene-group in an intramolecular charge transfer character of a short fucoxanthin homolog as revealed by femtosecond pump-probe spectroscopy. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.04.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Kosumi D, Kajikawa T, Okumura S, Sugisaki M, Sakaguchi K, Katsumura S, Hashimoto H. Elucidation and Control of an Intramolecular Charge Transfer Property of Fucoxanthin by a Modification of Its Polyene Chain Length. J Phys Chem Lett 2014; 5:792-797. [PMID: 26274069 DOI: 10.1021/jz5000287] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Fucoxanthin is an essential pigment for the highly efficient light-harvesting function of marine algal photosynthesis. It exhibits excited state properties attributed to intramolecular charge transfer (ICT) in polar environments due to the presence of the carbonyl group in its polyene backbone. This report describes the excited state properties of fucoxanthin homologues with four to eight conjugated double bonds in various solvents using the femtosecond pump-probe technique. The results clarified that fucoxanthin homologues with longer polyene chains did not possess pronounced ICT spectroscopic signatures, while the shorter fucoxanthin homologues had a strong ICT character, even in a nonpolar solvent. On the basis of the observations, we quantitatively correlated the ICT character in the excited state to the conjugated polyene chain lengths of fucoxanthin molecules.
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Affiliation(s)
- Daisuke Kosumi
- †Osaka City University Advanced Research Institute for Natural Science and Technology (OCARINA), 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Takayuki Kajikawa
- ‡Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda, Hyogo 669-1337, Japan
| | - Satoshi Okumura
- ‡Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda, Hyogo 669-1337, Japan
| | - Mitsuru Sugisaki
- §Department of Physics, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Kazuhiko Sakaguchi
- ∥Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Shigeo Katsumura
- ‡Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda, Hyogo 669-1337, Japan
| | - Hideki Hashimoto
- †Osaka City University Advanced Research Institute for Natural Science and Technology (OCARINA), 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
- §Department of Physics, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
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11
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Fuciman M, Durchan M, Šlouf V, Keşan G, Polívka T. Excited-state dynamics of astaxanthin aggregates. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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12
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Christensson N, Žídek K, Magdaong NCM, LaFountain AM, Frank HA, Zigmantas D. Origin of the Bathochromic Shift of Astaxanthin in Lobster Protein: 2D Electronic Spectroscopy Investigation of β-Crustacyanin. J Phys Chem B 2013; 117:11209-19. [DOI: 10.1021/jp401873k] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Niklas Christensson
- Faculty of Physics, University of Vienna, Strudlhofgasse 4, 1090 Vienna,
Austria
| | - Karel Žídek
- Department of Chemical
Physics, Lund University, Box 124, 21000,
Lund, Sweden
| | - Nikki Cecil M. Magdaong
- Department of
Chemistry, University of Connecticut, Storrs,
Connecticut 06269-3060,
United States
| | - Amy M. LaFountain
- Department of
Chemistry, University of Connecticut, Storrs,
Connecticut 06269-3060,
United States
| | - Harry A. Frank
- Department of
Chemistry, University of Connecticut, Storrs,
Connecticut 06269-3060,
United States
| | - Donatas Zigmantas
- Department of Chemical
Physics, Lund University, Box 124, 21000,
Lund, Sweden
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13
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Durchan M, Fuciman M, Šlouf V, Keşan G, Polívka T. Excited-State Dynamics of Monomeric and Aggregated Carotenoid 8′-Apo-β-carotenal. J Phys Chem A 2012; 116:12330-8. [DOI: 10.1021/jp310140k] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Milan Durchan
- Institute
of Physics and Biophysics, Faculty of Science, University of South Bohemia, Branišovská
31, České Budějovice, Czech Republic
| | - Marcel Fuciman
- Institute
of Physics and Biophysics, Faculty of Science, University of South Bohemia, Branišovská
31, České Budějovice, Czech Republic
| | - Václav Šlouf
- Institute
of Physics and Biophysics, Faculty of Science, University of South Bohemia, Branišovská
31, České Budějovice, Czech Republic
| | - Gürkan Keşan
- Institute
of Physics and Biophysics, Faculty of Science, University of South Bohemia, Branišovská
31, České Budějovice, Czech Republic
| | - Tomáš Polívka
- Institute
of Physics and Biophysics, Faculty of Science, University of South Bohemia, Branišovská
31, České Budějovice, Czech Republic
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14
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Alster J, Polívka T, Arellano JB, Hříbek P, Vácha F, Hála J, Pšenčík J. Self-assembly and energy transfer in artificial light-harvesting complexes of bacteriochlorophyll c with astaxanthin. PHOTOSYNTHESIS RESEARCH 2012; 111:193-204. [PMID: 21833799 DOI: 10.1007/s11120-011-9670-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 07/02/2011] [Indexed: 05/31/2023]
Abstract
Chlorosomes, the light-harvesting antennae of green photosynthetic bacteria, are based on large aggregates of bacteriochlorophyll molecules. Aggregates with similar properties to those in chlorosomes can also be prepared in vitro. Several agents were shown to induce aggregation of bacteriochlorophyll c in aqueous environments, including certain lipids, carotenes, and quinones. A key distinguishing feature of bacteriochlorophyll c aggregates, both in vitro and in chlorosomes, is a large (>60 nm) red shift of their Q(y) absorption band compared with that of the monomers. In this study, we investigate the self-assembly of bacteriochlorophyll c with the xanthophyll astaxanthin, which leads to the formation of a new type of complexes. Our results indicate that, due to its specific structure, astaxanthin molecules competes with bacteriochlorophylls for the bonds involved in the aggregation, thus preventing the formation of any significant red shift compared with pure bacteriochlorophyll c in aqueous buffer. A strong interaction between both the types of pigments in the developed assemblies, is manifested by a rather efficient (~40%) excitation energy transfer from astaxanthin to bacteriochlorophyll c, as revealed by fluorescence excitation spectroscopy. Results of transient absorption spectroscopy show that the energy transfer is very fast (<500 fs) and proceeds through the S(2) state of astaxanthin.
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Affiliation(s)
- J Alster
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16, Praha, Czech Republic
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15
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Polívka T, Kaligotla S, Chábera P, Frank HA. An intramolecular charge transfer state of carbonyl carotenoids: implications for excited state dynamics of apo-carotenals and retinal. Phys Chem Chem Phys 2011; 13:10787-96. [PMID: 21552594 DOI: 10.1039/c1cp20269c] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Excited state dynamics of two apo-carotenals, retinal and 12'-apo-β-carotenal, were studied by femtosecond transient absorption spectroscopy. We make use of previous knowledge gathered from studies of various carbonyl carotenoids and suggest that to consistently explain the excited-state dynamics of retinal in polar solvents, it is necessary to include an intermolecular charge transfer (ICT) state in the excited state manifold. Coupling of the ICT state to the A(g)(-) state, which occurs in polar solvents, shortens lifetime of the lowest excited state of 12'-apo-β-carotenal from 180 ps in n-hexane to 7.1 ps in methanol. Comparison with a reference molecule lacking the conjugated carbonyl group, 12'-apo-β-carotene, demonstrates the importance of the carbonyl group; no polarity-induced lifetime change is observed and 12'-apo-β-carotene decays to the ground state in 220 ps regardless of solvent polarity. For retinal, we have confirmed the well-known three-state relaxation scheme in n-hexane. Population of the B(u)(+) state decays in <100 fs to the A(g)(-) state, which is quenched in 440 fs by a low-lying nπ* state that decays with a 33 ps time constant to form the retinal triplet state. In methanol, however, the A(g)(-) state is coupled to the ICT state. This coupling prevents population of the nπ* state, which explains the absence of retinal triplet formation in polar solvents. Instead, the coupled A(g)(-)/ICT state decays in 1.6 ps to the ground state. The A(g)(-)/ICT coupling is also evidenced by stimulated emission, which is a characteristic marker of the ICT state in carbonyl carotenoids.
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Affiliation(s)
- Tomáš Polívka
- Institute of Physical Biology, University of South Bohemia, Zámek 136, 373 33 Nové, Hrady, Czech Republic.
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16
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Kosumi D, Kusumoto T, Fujii R, Sugisaki M, Iinuma Y, Oka N, Takaesu Y, Taira T, Iha M, Frank HA, Hashimoto H. Ultrafast excited state dynamics of fucoxanthin: excitation energy dependent intramolecular charge transfer dynamics. Phys Chem Chem Phys 2011; 13:10762-70. [DOI: 10.1039/c0cp02568b] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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17
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Excited-state properties of the 16 kDa red carotenoid protein from Arthrospira maxima. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:30-5. [DOI: 10.1016/j.bbabio.2010.08.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 08/21/2010] [Accepted: 08/24/2010] [Indexed: 10/19/2022]
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18
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Enriquez MM, Fuciman M, LaFountain AM, Wagner NL, Birge RR, Frank HA. The intramolecular charge transfer state in carbonyl-containing polyenes and carotenoids. J Phys Chem B 2010; 114:12416-26. [PMID: 20825184 PMCID: PMC2950165 DOI: 10.1021/jp106113h] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Numerous femtosecond time-resolved optical spectroscopic experiments have reported that the lifetime of the low-lying S(1) state of carbonyl-containing polyenes and carotenoids decreases with increasing solvent polarity. The effect becomes even more pronounced as the number of double bonds in the conjugated π-electron system decreases. The effect has been attributed to an intramolecular charge transfer (ICT) state coupled to S(1), but it is still not clear what the precise molecular nature of this state is, and how it is able to modulate the spectral and dynamic properties of polyenes and carotenoids. In this work, we examine the nature of the ICT state in three substituted polyenes: crocetindial, which contains two terminal, symmetrically substituted carbonyl groups in conjugation with the π-electron system, 8,8'-diapocarotene-8'-ol-8-al, which has one terminal conjugated carbonyl group and one hydroxyl group, and 8,8'-diapocarotene-8,8'-diol, which has two terminal, symmetrically positioned, hydroxyl groups but no carbonyls. Femtosecond time-resolved optical spectroscopic experiments on these molecules reveal that only the asymmetrically substituted 8,8'-diapocarotene-8'-ol-8-al exhibits any substantial effect of solvent on the excited state spectra and dynamics. The data are interpreted using molecular orbital theory which shows that the ICT state develops via mixing of the low-lying S(1) (2(1)A(g)-like) and S(2) (1(1)B(u)-like) excited singlet states to form a resultant state that preferentially evolves in polar solvent and exhibits a very large (∼25 D) dipole moment. Molecular dynamics calculations demonstrate that the features of the ICT state are present in ∼20 fs.
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Affiliation(s)
- Miriam M. Enriquez
- Department of Chemistry, University of Connecticut, U-3060, 55 North Eagleville Road, Storrs, CT 06269-3060, USA
| | - Marcel Fuciman
- Department of Chemistry, University of Connecticut, U-3060, 55 North Eagleville Road, Storrs, CT 06269-3060, USA
| | - Amy M. LaFountain
- Department of Chemistry, University of Connecticut, U-3060, 55 North Eagleville Road, Storrs, CT 06269-3060, USA
| | - Nicole L. Wagner
- Department of Chemistry, University of Connecticut, U-3060, 55 North Eagleville Road, Storrs, CT 06269-3060, USA
| | - Robert R. Birge
- Department of Chemistry, University of Connecticut, U-3060, 55 North Eagleville Road, Storrs, CT 06269-3060, USA
| | - Harry A. Frank
- Department of Chemistry, University of Connecticut, U-3060, 55 North Eagleville Road, Storrs, CT 06269-3060, USA
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