1
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Carroll JA, Pashley-Johnson F, Frisch H, Barner-Kowollik C. Photochemical Action Plots Reveal Red-shifted Wavelength-dependent Photoproduct Distributions. Chemistry 2024; 30:e202304174. [PMID: 38267371 DOI: 10.1002/chem.202304174] [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: 12/14/2023] [Revised: 01/15/2024] [Accepted: 01/24/2024] [Indexed: 01/26/2024]
Abstract
Photochemical action plots are a powerful tool for mapping photochemical reaction outcomes wavelength-by-wavelength. Typically, they map either the depletion of a reactant or the formation of a specific product as a function of wavelength. Herein, we exploit action plots to simultaneously map the formation of several photochemical products from a single chromophore. We demonstrate that the wavelength-resolved mapping of two reaction products formed during the irradiation of a chalcone species not only shows wavelength dependence - exhibiting the typical strong red-shift of the photochemical reactivity compared to the absorbance spectrum of the chromophore - but also a strong wavelength selectivity with remarkably different product distributions resulting from different irradiation wavelengths.
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Affiliation(s)
- Joshua A Carroll
- School of Chemistry and Physics, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia
- Centre for Materials Science, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia
| | - Fred Pashley-Johnson
- School of Chemistry and Physics, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia
- Centre for Materials Science, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia
- Department of Organic and Macromolecular Chemistry, Polymer Chemistry Research Group, Centre of Macromolecular Chemistry (CMaC), Faculty of Science, Ghent University, Krijgslaan 281 (S4-Bis), 9000, Ghent, Belgium
| | - Hendrik Frisch
- School of Chemistry and Physics, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia
- Centre for Materials Science, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia
| | - Christopher Barner-Kowollik
- School of Chemistry and Physics, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia
- Centre for Materials Science, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia
- Insitute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
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2
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Mujawar T, Sevelda P, Madea D, Klán P, Švenda J. A Platform for the Synthesis of Oxidation Products of Bilirubin. J Am Chem Soc 2024; 146:1603-1611. [PMID: 38165253 PMCID: PMC10797625 DOI: 10.1021/jacs.3c11778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/30/2023] [Accepted: 12/06/2023] [Indexed: 01/03/2024]
Abstract
Bilirubin is the principal product of heme catabolism. High concentrations of the pigment are neurotoxic, yet slightly elevated levels are beneficial. Being a potent antioxidant, oxidative transformations of bilirubin occur in vivo and lead to various oxidized fragments. The mechanisms of their formation, intrinsic biological activities, and potential roles in human pathophysiology are poorly understood. Degradation methods have been used to obtain samples of bilirubin oxidation products for research. Here, we report a complementary, fully synthetic method of preparation. Our strategy leverages repeating substitution patterns in the parent tetracyclic pigment. Functionalized ready-to-couple γ-lactone, γ-lactam, and pyrrole monocyclic building blocks were designed and efficiently synthesized. Subsequent modular combinations, supported by metal-catalyzed borylation and cross-coupling chemistries, translated into the concise assembly of the structurally diverse bilirubin oxidation products (BOXes, propentdyopents, and biopyrrins). The discovery of a new photoisomer of biopyrrin A named lumipyrrin is reported. Synthetic bilirubin oxidation products made available in sufficient purity and quantity will support future in vitro and in vivo investigations.
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Affiliation(s)
- Taufiqueahmed Mujawar
- Department
of Chemistry, Faculty of Science, Masaryk
University, Kamenice 5, Brno 625 00, Czech Republic
| | - Petr Sevelda
- Department
of Chemistry, Faculty of Science, Masaryk
University, Kamenice 5, Brno 625 00, Czech Republic
| | - Dominik Madea
- Department
of Chemistry, Faculty of Science, Masaryk
University, Kamenice 5, Brno 625 00, Czech Republic
- RECETOX,
Faculty of Science, Masaryk University, Kamenice 5, Brno 625 00, Czech Republic
| | - Petr Klán
- Department
of Chemistry, Faculty of Science, Masaryk
University, Kamenice 5, Brno 625 00, Czech Republic
- RECETOX,
Faculty of Science, Masaryk University, Kamenice 5, Brno 625 00, Czech Republic
| | - Jakub Švenda
- Department
of Chemistry, Faculty of Science, Masaryk
University, Kamenice 5, Brno 625 00, Czech Republic
- International
Clinical Research Center, St. Anne’s
University Hospital, Pekařská 53, Brno 656 91, Czech Republic
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3
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Cruz ÁB, de Brito LG, Leal PVB, Dos Santos Ramos WT, Pereira DH. Intramolecular hydrogen bonds interactions in the isomers of the bilirubin molecule: DFT and QTAIM analysis. J Mol Model 2023; 29:318. [PMID: 37718354 DOI: 10.1007/s00894-023-05720-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 09/02/2023] [Indexed: 09/19/2023]
Abstract
CONTEXT Bilirubin is an important molecule, used as a marker of some liver diseases, and it can also be toxic and cause jaundice, especially in newborns. The main treatment for neonatal jaundice is phototherapy with blue light, which is still widely studied because the photophysical processes involved are not fully understood. METHODS Calculations based on the density functional theory (DFT) at M062X/6-31G(d,p) level were performed in order to evaluate the structural, electronic, and topological properties of bilirubin isomers. It was found that the ZZ conformation can form a greater number of hydrogen bonds, which gives the isomer greater energy stabilization compared to the other ZE, EZ, and EE isomers, and that the EE isomer is the conformer with the lowest energy of stabilization. The hydrogen bonds were characterized by the quantum theory of atoms in molecules (QTAIM) and for the ZZ isomer four hydrogen bonds (HBs) were found classified as intermediate, ∇2ρ(r) > 0, H(r) > 0. The ZE, EZ, and EE isomers show weak HBs, ∇2ρ(r) > 0, H(r) > 0.
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Affiliation(s)
- Állefe Barbosa Cruz
- Collegiate of Exact Sciences and Biotechnology, Federal University of Tocantins, 77.402-970, Gurupi, Tocantins, Brazil
- Graduate Program in Chemistry, Federal University of Tocantins, 77.402-970, Gurupi, Tocantins, Brazil
| | - Lívia Gabriela de Brito
- Institute of Engineering, Science and Technology, Universidade Federal Dos Vales Do Jequitinhonha E Mucuri, Janaúba, MG, 39440-000, Brazil
| | - Paulo Vitor Brandão Leal
- Institute of Engineering, Science and Technology, Universidade Federal Dos Vales Do Jequitinhonha E Mucuri, Janaúba, MG, 39440-000, Brazil
| | - Welyson Tiano Dos Santos Ramos
- Institute of Engineering, Science and Technology, Universidade Federal Dos Vales Do Jequitinhonha E Mucuri, Janaúba, MG, 39440-000, Brazil
- Graduate Program On Computacional Modeling and Systems, Universidade Estadual de Montes Claros, Montes Claros, MG, 39401-089, Brazil
| | - Douglas Henrique Pereira
- Collegiate of Exact Sciences and Biotechnology, Federal University of Tocantins, 77.402-970, Gurupi, Tocantins, Brazil.
- Graduate Program in Chemistry, Federal University of Tocantins, 77.402-970, Gurupi, Tocantins, Brazil.
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4
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Yang Q, Váňa J, Klán P. The complex photochemistry of coumarin-3-carboxylic acid in acetonitrile and methanol. Photochem Photobiol Sci 2022; 21:1481-1495. [PMID: 35578152 DOI: 10.1007/s43630-022-00238-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 04/23/2022] [Indexed: 11/26/2022]
Abstract
Irradiation of coumarin-3-carboxylic acid in acetonitrile and methanol solutions at 355 nm results in complex multistep photochemical transformations, strongly dependent on the solvent properties and oxygen content. A number of reaction intermediates, which themselves undergo further (photo)chemical reactions, were identified by steady-state and transient absorption spectroscopy, mass spectrometry, and NMR and product analyses. The triplet excited compound in acetonitrile undergoes decarboxylation to give a 3-coumarinyl radical that traps molecular oxygen to form 3-hydroxycoumarin as the major but chemically reactive intermediate. This compound is oxygenated by singlet oxygen, produced by coumarin-3-carboxylic acid sensitization, followed by a pyrone ring-opening reaction to give an oxalic acid derivative. The subsequent steps lead to the production of salicylaldehyde, carbon monoxide, and carbon dioxide as the final products. When 3-coumarinyl radical is not trapped by oxygen in degassed acetonitrile, it abstracts hydrogen from the solvent and undergoes triplet-sensitized [2 + 2] cycloaddition. The reaction of 3-coumarinyl radical with oxygen is largely suppressed in aerated methanol as a better H-atom donor, and coumarin is obtained as the primary product in good yields. Because coumarin derivatives are used in many photophysical and photochemical applications, this work provides detailed and sometimes surprising insights into their complex phototransformations.
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Affiliation(s)
- Qiuyun Yang
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, Brno, Czech Republic
- RECETOX, Faculty of Science, Masaryk University, Kamenice 5, Brno, Czech Republic
| | - Jiří Váňa
- Institute of Organic Chemistry and Technology, Faculty of Chemical Technology, University of Pardubice, Studentská 573, Pardubice, Czech Republic
| | - Petr Klán
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, Brno, Czech Republic.
- RECETOX, Faculty of Science, Masaryk University, Kamenice 5, Brno, Czech Republic.
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5
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Madea D, Mujawar T, Dvořák A, Pospíšilová K, Muchová L, Čubáková P, Kloz M, Švenda J, Vítek L, Klán P. Photochemistry of ( Z)-Isovinylneoxanthobilirubic Acid Methyl Ester, a Bilirubin Dipyrrinone Subunit: Femtosecond Transient Absorption and Stimulated Raman Emission Spectroscopy. J Org Chem 2022; 87:3089-3103. [PMID: 35130431 DOI: 10.1021/acs.joc.1c02870] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bilirubin (BR) is an essential metabolite formed by the catabolism of heme. Phototherapy with blue-green light can be applied to reduce high concentrations of BR in blood and is used especially in the neonatal period. In this work, we studied the photochemistry of (Z)-isovinylneoxanthobilirubic acid methyl ester, a dipyrrinone subunit of BR, by steady-state absorption, femtosecond transient absorption, and stimulated Raman spectroscopies. Both the (Z)- and (E)-configurational isomers of isovinylneoxanthobilirubic acid undergo wavelength-dependent and reversible photoisomerization. The isomerization from the excited singlet state is ultrafast (the lifetimes of (Z)- and (E)-isomers were found to be ∼0.9 and 0.1 ps, respectively), and its efficiencies increase with increased photon energy. In addition, we studied sensitized photooxidation of the dipyrrinone subunit by singlet oxygen that leads to the formation of propentdyopents. Biological activities of these compounds, namely, effects on the superoxide production, lipoperoxidation, and tricarboxylic acid cycle metabolism, were also studied. Finally, different photochemical and biological properties of this BR subunit and its structural analogue, (Z)-vinylneoxanthobilirubic acid methyl ester, studied before, are discussed.
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Affiliation(s)
- Dominik Madea
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,RECETOX, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Taufiqueahmed Mujawar
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Aleš Dvořák
- Institute of Medical Biochemistry and Laboratory Diagnostics, General University Hospital in Prague and 1st Faculty of Medicine, Charles University, Na Bojišti 3, 121 08 Prague 2, Czech Republic
| | - Kateřina Pospíšilová
- Institute of Medical Biochemistry and Laboratory Diagnostics, General University Hospital in Prague and 1st Faculty of Medicine, Charles University, Na Bojišti 3, 121 08 Prague 2, Czech Republic
| | - Lucie Muchová
- Institute of Medical Biochemistry and Laboratory Diagnostics, General University Hospital in Prague and 1st Faculty of Medicine, Charles University, Na Bojišti 3, 121 08 Prague 2, Czech Republic
| | - Petra Čubáková
- Institute of Physics of the Czech Academy of Sciences, ELI Beamlines, Za Radnicí 835, 252 41 Dolní Břežany, Czech Republic.,University of South Bohemia in České Budějovice, Branišovská, 1645/31a, 370 05 České Budějovice, Czech Republic
| | - Miroslav Kloz
- University of South Bohemia in České Budějovice, Branišovská, 1645/31a, 370 05 České Budějovice, Czech Republic
| | - Jakub Švenda
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Libor Vítek
- Institute of Medical Biochemistry and Laboratory Diagnostics, and 4th Department of Internal Medicine, General University Hospital in Prague and 1st Faculty of Medicine, Charles University, Na Bojišti 3, 121 08 Prague 2, Czech Republic
| | - Petr Klán
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,RECETOX, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
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6
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Liao JW, Sung R, Sung K. Against the NEER principle: the third type of photochromism for GFP chromophore derivatives. Phys Chem Chem Phys 2021; 24:295-304. [PMID: 34889318 DOI: 10.1039/d1cp03581a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photochromism is the heart of photochromic fluorescent proteins. Excited-state proton transfer (ESPT) is the major cause of photochromism for the green fluorescent protein (GFP) and Z-E photoisomerization through τ-torsion is the major cause of photochromism for Dronpa (a GFP mutant). In this article, s-E-1 opens a third type of photochromism for GFP chromophore derivatives, which involves light-driven φ-torsion with no τ-torsion, followed by excited-state intramolecular proton transfer (ESIPT), and is gated by environmental polarity. Since s-E-1 does not follow Z-E photoisomerization through τ-torsion but undergoes light-driven φ-torsion, which involves equilibration of the excited-state rotamers, it is clearly against the NEER (Non-Equilibration of Excited-state Rotamers) principle.
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Affiliation(s)
- Jun-Wei Liao
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan.
| | - Robert Sung
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan.
| | - Kuangsen Sung
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan.
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7
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Hermanns V, Scheurer M, Kersten NF, Abdellaoui C, Wachtveitl J, Dreuw A, Heckel A. Rethinking Uncaging: A New Antiaromatic Photocage Driven by a Gain of Resonance Energy. Chemistry 2021; 27:14121-14127. [PMID: 34363415 PMCID: PMC8519059 DOI: 10.1002/chem.202102351] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Indexed: 12/31/2022]
Abstract
Photoactivatable compounds for example photoswitches or photolabile protecting groups (PPGs, photocages) for spatiotemporal light control, play a crucial role in different areas of research. For each application, parameters such as the absorption spectrum, solubility in the respective media and/or photochemical quantum yields for several competing processes need to be optimized. The design of new photochemical tools therefore remains an important task. In this study, we exploited the concept of excited-state-aromaticity, first described by N. Colin Baird in 1971, to investigate a new class of photocages, based on cyclic, ground-state-antiaromatic systems. Several thio- and nitrogen-functionalized compounds were synthesized, photochemically characterized and further optimized, supported by quantum chemical calculations. After choosing the optimal scaffold, which shows an excellent uncaging quantum yield of 28 %, we achieved a bathochromic shift of over 100 nm, resulting in a robust, well accessible, visible light absorbing, compact new photocage with a clean photoreaction and a high quantum product (ϵ⋅Φ) of 893 M-1 cm-1 at 405 nm.
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Affiliation(s)
- Volker Hermanns
- Institute of Organic Chemistry and Chemical BiologyGoethe University FrankfurtMax-von-Lau-Str. 760438FrankfurtGermany
| | - Maximilian Scheurer
- Interdisciplinary Center for Scientific ComputingHeidelberg UniversityIm Neuenheimer Feld 20569120HeidelbergGermany
| | - Nils Frederik Kersten
- Institute of Organic Chemistry and Chemical BiologyGoethe University FrankfurtMax-von-Lau-Str. 760438FrankfurtGermany
| | - Chahinez Abdellaoui
- Institute of Physical and Theoretical ChemistryGoethe University FrankfurtMax-von-Laue-Str. 760438FrankfurtGermany
| | - Josef Wachtveitl
- Institute of Physical and Theoretical ChemistryGoethe University FrankfurtMax-von-Laue-Str. 760438FrankfurtGermany
| | - Andreas Dreuw
- Interdisciplinary Center for Scientific ComputingHeidelberg UniversityIm Neuenheimer Feld 20569120HeidelbergGermany
| | - Alexander Heckel
- Institute of Organic Chemistry and Chemical BiologyGoethe University FrankfurtMax-von-Lau-Str. 760438FrankfurtGermany
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8
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Liu YY, Pan HF, Xu JH, Chen JQ. Long chain fatty acid affects excited state branching in bilirubin-human serum protein Complex. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2012220] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Yang-yi Liu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Hai-feng Pan
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Jian-hua Xu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
| | - Jin-quan Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
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9
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El-Zohry AM, Diez-Cabanes V, Pastore M, Ahmed T, Zietz B. Highly Emissive Biological Bilirubin Molecules: Shedding New Light on the Phototherapy Scheme. J Phys Chem B 2021; 125:9213-9222. [PMID: 34346676 PMCID: PMC8389986 DOI: 10.1021/acs.jpcb.1c05308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bilirubin (BR) is the main end-product of the hemoglobin catabolism. For decades, its photophysics has been mainly discussed in terms of ultrafast deactivation of the excited state in solution, where, indeed, BR shows a very low green emission quantum yield (EQY), 0.03%, resulting from an efficient nonradiative isomerization process. Herein, we present, for the first time, unique and exceptional photophysical properties of solid-state BR, which amend by changing the type of crystal, from a closely packed α crystal to an amorphous loosely packed β crystal. BR α crystals show a very bright red emission with an EQY of ca. 24%, whereas β crystals present, in addition, a low green EQY of ca. 0.5%. By combining density functional theory (DFT) calculations and time-resolved emission spectroscopy, we trace back this dual emission to the presence of two types of BR molecules in the crystal: a "stiff" monomer, M1, distorted by particularly strong internal H-bonds and a "floppy" monomer, M2, having a structure close to that of BR in solution. We assign the red strong emission of BR crystals to M1 present in both the α and β crystals, while the low green emission, only present in the amorphous (β) crystal, is interpreted as M2 emission. Efficient energy-transfer processes from M2 to M1 in the closely packed α crystal are invoked to explain the absence of the green component in its emission spectrum. Interestingly, these unique photophysical properties of BR remain in polar solvents such as water. Based on these unprecedented findings, we propose a new model for the phototherapy scheme of BR inside the human body and highlight the usefulness of BR as a strong biological fluorescent probe.
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Affiliation(s)
- Ahmed M El-Zohry
- Department of Chemistry, Ångström Laboratories, Box 523, SE-75120 Uppsala, Sweden.,Department of Physics - AlbaNova Universitetscentrum, Stockholm University, SE-10691 Stockholm, Sweden
| | - Valentin Diez-Cabanes
- Université de Lorraine & CNRS, Laboratoire de Physique et Chimie Théoriques (LPCT), F-54000 Nancy, France
| | - Mariachiara Pastore
- Université de Lorraine & CNRS, Laboratoire de Physique et Chimie Théoriques (LPCT), F-54000 Nancy, France
| | - Taha Ahmed
- Department of Chemistry, Ångström Laboratories, Box 523, SE-75120 Uppsala, Sweden
| | - Burkhard Zietz
- Department of Chemistry, Ångström Laboratories, Box 523, SE-75120 Uppsala, Sweden
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10
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Janoš J, Madea D, Mahvidi S, Mujawar T, Švenda J, Suchan J, Slavíček P, Klán P. Conformational Control of the Photodynamics of a Bilirubin Dipyrrinone Subunit: Femtosecond Spectroscopy Combined with Nonadiabatic Simulations. J Phys Chem A 2020; 124:10457-10471. [PMID: 33283519 DOI: 10.1021/acs.jpca.0c08945] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The photochemistry of bilirubin has been extensively studied due to its importance in the phototherapy of hyperbilirubinemia. In the present work, we investigated the ultrafast photodynamics of a bilirubin dipyrrinone subunit, vinylneoxanthobilirubic acid methyl ester. The photoisomerization and photocyclization reactions of its (E) and (Z) isomers were studied using femtosecond transient absorption spectroscopy and by multireference electronic structure theory, where the nonadiabatic dynamics was modeled with a Landau-Zener surface hopping technique. The following picture has emerged from the combined theoretical and experimental approach. Upon excitation, dipyrrinone undergoes a very fast vibrational relaxation, followed by an internal conversion on a picosecond time scale. The internal conversion leads either to photoisomerization or regeneration of the starting material. Further relaxation dynamics on the order of tens of picoseconds was observed in the ground state. The nonadiabatic simulations revealed a strong conformational control of the photodynamics. The ultrafast formation of a cyclic photochemical product from a less-populated conformer of the studied subunit was predicted by our calculations. We discuss the relevance of the present finding for the photochemistry of native bilirubin. The work has also pointed to the limits of semiclassical nonadiabatic simulations for simulating longer photochemical processes, probably due to the zero-point leakage issue.
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Affiliation(s)
- Jiří Janoš
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, Prague 6, Czech Republic
| | - Dominik Madea
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,RECETOX, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Sadegh Mahvidi
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,RECETOX, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Taufiqueahmed Mujawar
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Jakub Švenda
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Jiří Suchan
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, Prague 6, Czech Republic
| | - Petr Slavíček
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, Prague 6, Czech Republic
| | - Petr Klán
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,RECETOX, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
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