1
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Multielectron Transfer Sensitization of Flavin Cofactor Recycling. INORG CHEM COMMUN 2023. [DOI: 10.1016/j.inoche.2023.110444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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2
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Zhang HH, Yu S, Zhao JJ. Enantioselective Radical Functionalization of Imines and Iminium Intermediates via Visible-Light Photoredox Catalysis. SYNTHESIS-STUTTGART 2020. [DOI: 10.1055/a-1343-6541] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
AbstractVisible-light photoredox catalysis has recently emerged as a powerful tool for the development of new and valuable chemical transformations under mild conditions. Visible-light promoted enantioselective radical transformations of imines and iminium intermediates provide new opportunities for the asymmetric synthesis of amines and the asymmetric β-functionalization of unsaturated carbonyl compounds. In this review, recent advances on the catalytic asymmetric radical functionalization of imines and iminium intermediates are summarized.1 Introduction2 Enantioselective Radical Functionalization of Imines2.1 Asymmetric Reduction2.2 Asymmetric Cyclization2.3 Asymmetric Addition2.4 Asymmetric Radical–Radical Coupling 3 Enantioselective Radical Functionalization of Iminium Ions3.1 Asymmetric Radical Alkylation3.2 Asymmetric Radical Acylation4 Conclusion
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3
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Weinstain R, Slanina T, Kand D, Klán P. Visible-to-NIR-Light Activated Release: From Small Molecules to Nanomaterials. Chem Rev 2020; 120:13135-13272. [PMID: 33125209 PMCID: PMC7833475 DOI: 10.1021/acs.chemrev.0c00663] [Citation(s) in RCA: 258] [Impact Index Per Article: 64.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Indexed: 02/08/2023]
Abstract
Photoactivatable (alternatively, photoremovable, photoreleasable, or photocleavable) protecting groups (PPGs), also known as caged or photocaged compounds, are used to enable non-invasive spatiotemporal photochemical control over the release of species of interest. Recent years have seen the development of PPGs activatable by biologically and chemically benign visible and near-infrared (NIR) light. These long-wavelength-absorbing moieties expand the applicability of this powerful method and its accessibility to non-specialist users. This review comprehensively covers organic and transition metal-containing photoactivatable compounds (complexes) that absorb in the visible- and NIR-range to release various leaving groups and gasotransmitters (carbon monoxide, nitric oxide, and hydrogen sulfide). The text also covers visible- and NIR-light-induced photosensitized release using molecular sensitizers, quantum dots, and upconversion and second-harmonic nanoparticles, as well as release via photodynamic (photooxygenation by singlet oxygen) and photothermal effects. Release from photoactivatable polymers, micelles, vesicles, and photoswitches, along with the related emerging field of photopharmacology, is discussed at the end of the review.
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Affiliation(s)
- Roy Weinstain
- School
of Plant Sciences and Food Security, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 6997801, Israel
| | - Tomáš Slanina
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague, Czech Republic
| | - Dnyaneshwar Kand
- School
of Plant Sciences and Food Security, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 6997801, Israel
| | - Petr Klán
- Department
of Chemistry and RECETOX, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
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4
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Capaldo L, Ertl M, Fagnoni M, Knör G, Ravelli D. Antimony-Oxo Porphyrins as Photocatalysts for Redox-Neutral C-H to C-C Bond Conversion. ACS Catal 2020; 10:9057-9064. [PMID: 33815891 PMCID: PMC8009479 DOI: 10.1021/acscatal.0c02250] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/16/2020] [Indexed: 02/03/2023]
Abstract
The use of high-valent antimony-oxo porphyrins as visible-light photocatalysts operating via direct hydrogen atom transfer has been demonstrated. Computational analysis indicates that the triplet excited state of these complexes shows an oxyl radical behavior, while the SbV center remains in a high-valent oxidation state, serving uniquely to carry the oxo moiety and activate the coordinated ligands. This porphyrin-based system has been exploited upon irradiation to catalyze C-H to C-C bond conversion via the addition of hydrogen donors (ethers and aldehydes) onto Michael acceptors in a redox-neutral fashion without the need of any external oxidant. Laser flash photolysis experiments confirmed that the triplet excited state of the photocatalyst triggers the desired C-H cleavage.
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Affiliation(s)
- Luca Capaldo
- PhotoGreen Lab, Department of Chemistry, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
| | - Martin Ertl
- Institute of Inorganic Chemistry, Johannes Kepler University Linz (JKU), Altenberger Strasse 69, 4040 Linz, Austria
| | - Maurizio Fagnoni
- PhotoGreen Lab, Department of Chemistry, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
| | - Günther Knör
- Institute of Inorganic Chemistry, Johannes Kepler University Linz (JKU), Altenberger Strasse 69, 4040 Linz, Austria
| | - Davide Ravelli
- PhotoGreen Lab, Department of Chemistry, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
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5
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Hajimohammadi M, Azizi N, Tollabimazraeno S, Tuna A, Duchoslav J, Knör G. Cobalt (II) Phthalocyanine Sulfonate Supported on Reduced Graphene Oxide (RGO) as a Recyclable Photocatalyst for the Oxidation of Aldehydes to Carboxylic Acids. Catal Letters 2020. [DOI: 10.1007/s10562-020-03287-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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6
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Reichl E, Ertl M, Knör G. Multielectron Redox Catalysis with Efficient Tyrosinase Activity Based on a Visible-Light Controlled Artificial Photoenzyme. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Eva Reichl
- Institute of Inorganic Chemistry; Johannes Kepler University Linz; Altenberger Strasse 69 4040 Linz Austria
| | - Martin Ertl
- Institute of Inorganic Chemistry; Johannes Kepler University Linz; Altenberger Strasse 69 4040 Linz Austria
- Linz School of Education; Altenberger Strasse 69 4040 Linz Austria
| | - Günther Knör
- Institute of Inorganic Chemistry; Johannes Kepler University Linz; Altenberger Strasse 69 4040 Linz Austria
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Senger M, Eichmann V, Laun K, Duan J, Wittkamp F, Knör G, Apfel UP, Happe T, Winkler M, Heberle J, Stripp ST. How [FeFe]-Hydrogenase Facilitates Bidirectional Proton Transfer. J Am Chem Soc 2019; 141:17394-17403. [PMID: 31580662 PMCID: PMC6823627 DOI: 10.1021/jacs.9b09225] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
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Hydrogenases are metalloenzymes that
catalyze the conversion of
protons and molecular hydrogen, H2. [FeFe]-hydrogenases
show particularly high rates of hydrogen turnover and have inspired
numerous compounds for biomimetic H2 production. Two decades
of research on the active site cofactor of [FeFe]-hydrogenases have
put forward multiple models of the catalytic proceedings. In comparison,
our understanding of proton transfer is poor. Previously, residues
were identified forming a hydrogen-bonding network between active
site cofactor and bulk solvent; however, the exact mechanism of catalytic
proton transfer remained inconclusive. Here, we employ in
situ infrared difference spectroscopy on the [FeFe]-hydrogenase
from Chlamydomonas reinhardtii evaluating dynamic
changes in the hydrogen-bonding network upon photoreduction. While
proton transfer appears to be impaired in the oxidized state (Hox), the presented data support continuous proton transfer
in the reduced state (Hred). Our analysis allows for
a direct, molecular unique assignment to individual amino acid residues.
We found that transient protonation changes of glutamic acid residue
E141 and, most notably, arginine R148 facilitate bidirectional proton
transfer in [FeFe]-hydrogenases.
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Affiliation(s)
- Moritz Senger
- Experimental Molecular Biophysics, Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Viktor Eichmann
- Experimental Molecular Biophysics, Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Konstantin Laun
- Experimental Molecular Biophysics, Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | | | | | - Günther Knör
- Institute of Inorganic Chemistry , Johannes Kepler Universität Linz , Altenberger Straße 69 , 4040 Linz , Austria
| | | | | | | | - Joachim Heberle
- Experimental Molecular Biophysics, Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Sven Timo Stripp
- Experimental Molecular Biophysics, Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
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Das A, Mandal I, Venkatramani R, Dasgupta J. Ultrafast photoactivation of C─H bonds inside water-soluble nanocages. SCIENCE ADVANCES 2019; 5:eaav4806. [PMID: 30801018 PMCID: PMC6386559 DOI: 10.1126/sciadv.aav4806] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 01/11/2019] [Indexed: 05/05/2023]
Abstract
Light energy absorbed by molecules can be harnessed to activate chemical bonds with extraordinary speed. However, excitation energy redistribution within various molecular degrees of freedom prohibits bond-selective chemistry. Inspired by enzymes, we devised a new photocatalytic scheme that preorganizes and polarizes target chemical bonds inside water-soluble cationic nanocavities to engineer selective functionalization. Specifically, we present a route to photoactivate weakly polarized sp3 C─H bonds in water via host-guest charge transfer and control its reactivity with aerial O2. Electron-rich aromatic hydrocarbons self-organize inside redox complementary supramolecular cavities to form photoactivatable host-guest charge transfer complexes in water. An ultrafast C─H bond cleavage within ~10 to 400 ps is triggered by visible-light excitation, through a cage-assisted and solvent water-assisted proton-coupled electron transfer reaction. The confinement prolongs the lifetime of the carbon-centered radical to enable a facile yet selective reaction with molecular O2 leading to photocatalytic turnover of oxidized products in water.
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Affiliation(s)
- Ankita Das
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Imon Mandal
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Ravindra Venkatramani
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Jyotishman Dasgupta
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
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Guo X, Okamoto Y, Schreier MR, Ward TR, Wenger OS. Enantioselective synthesis of amines by combining photoredox and enzymatic catalysis in a cyclic reaction network. Chem Sci 2018; 9:5052-5056. [PMID: 29938035 PMCID: PMC5994792 DOI: 10.1039/c8sc01561a] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 05/05/2018] [Indexed: 12/19/2022] Open
Abstract
Visible light-driven reduction of imines to enantioenriched amines in aqueous solution is demonstrated for the first time. Excitation of a new water-soluble variant of the widely used [Ir(ppy)3] (ppy = 2-phenylpyridine) photosensitizer in the presence of a cyclic imine affords a highly reactive α-amino alkyl radical that is intercepted by hydrogen atom transfer (HAT) from ascorbate or thiol donors to afford the corresponding amine. The enzyme monoamine oxidase (MAO-N-9) selectively catalyzes the oxidation of one of the enantiomers to the corresponding imine. Upon combining the photoredox and biocatalytic processes under continuous photo-irradiation, enantioenriched amines are obtained in excellent yields. To the best of our knowledge, this is the first demonstration of a concurrent photoredox- and enzymatic catalysis leading to a light-driven asymmetric synthesis of amines.
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Affiliation(s)
- Xingwei Guo
- Department of Chemistry , University of Basel , St. Johanns-Ring 19 , 4056 Basel , Switzerland .
| | - Yasunori Okamoto
- Department of Chemistry , University of Basel , Mattenstrasse 24a, BPR 1096 , 4002 Basel , Switzerland .
| | - Mirjam R Schreier
- Department of Chemistry , University of Basel , St. Johanns-Ring 19 , 4056 Basel , Switzerland .
| | - Thomas R Ward
- Department of Chemistry , University of Basel , Mattenstrasse 24a, BPR 1096 , 4002 Basel , Switzerland .
| | - Oliver S Wenger
- Department of Chemistry , University of Basel , St. Johanns-Ring 19 , 4056 Basel , Switzerland .
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10
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Wang L, Li Q. Photochromism into nanosystems: towards lighting up the future nanoworld. Chem Soc Rev 2018; 47:1044-1097. [PMID: 29251304 DOI: 10.1039/c7cs00630f] [Citation(s) in RCA: 312] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The ability to manipulate the structure and function of promising nanosystems via energy input and external stimuli is emerging as an attractive paradigm for developing reconfigurable and programmable nanomaterials and multifunctional devices. Light stimulus manifestly represents a preferred external physical and chemical tool for in situ remote command of the functional attributes of nanomaterials and nanosystems due to its unique advantages of high spatial and temporal resolution and digital controllability. Photochromic moieties are known to undergo reversible photochemical transformations between different states with distinct properties, which have been extensively introduced into various functional nanosystems such as nanomachines, nanoparticles, nanoelectronics, supramolecular nanoassemblies, and biological nanosystems. The integration of photochromism into these nanosystems has endowed the resultant nanostructures or advanced materials with intriguing photoresponsive behaviors and more sophisticated functions. In this Review, we provide an account of the recent advancements in reversible photocontrol of the structures and functions of photochromic nanosystems and their applications. The important design concepts of such truly advanced materials are discussed, their fabrication methods are emphasized, and their applications are highlighted. The Review is concluded by briefly outlining the challenges that need to be addressed and the opportunities that can be tapped into. We hope that the review of the flourishing and vibrant topic with myriad possibilities would shine light on exploring the future nanoworld by encouraging and opening the windows to meaningful multidisciplinary cooperation of engineers from different backgrounds and scientists from the fields such as chemistry, physics, engineering, biology, nanotechnology and materials science.
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Affiliation(s)
- Ling Wang
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242, USA.
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11
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Kianfar E, Apaydin DH, Knör G. Spin-Forbidden Excitation: A New Approach for Triggering Photopharmacological Processes with Low-Intensity NIR Light. CHEMPHOTOCHEM 2017; 1:378-382. [PMID: 29104916 PMCID: PMC5658980 DOI: 10.1002/cptc.201700086] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Indexed: 01/28/2023]
Abstract
Exposure to low-intensity radiation in the near-infrared (NIR) spectral region matching the optically transparent "phototherapeutic window" of biological tissues can be applied to directly populate spin-restricted excited states of light-responsive compounds. This unconventional and unprecedented approach is introduced herein as a new strategy to overcome some of the major unresolved problems observed in the rapidly emerging fields of photopharmacology and molecular photomedicine, where practical applications in living cells and organisms are still limited by undesired side reactions and insufficient light penetration. Water-soluble and biocompatible metal complexes with a significant degree of spin-orbit coupling were identified as target candidates for testing our new hypothesis. As a first example, a dark-stable manganese carbonyl complex acting as a visible-light-triggered CO-releasing molecule (Photo-CORM) is shown to be photoactivated by NIR radiation, although apparently no spectroscopically evident absorption bands are detectable in this low-energy region. This quite remarkable effect is ascribed to a strongly restricted, but obviously not completely forbidden optical population of the lowest triplet excited state manifold of the diamagnetic complex from the singlet ground state.
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Affiliation(s)
- Elham Kianfar
- Institute of Inorganic ChemistryJohannes Kepler University Linz (JKU)Altenbergerstrasse 69A-4040LinzAustria
| | - Dogukan Hazar Apaydin
- Institute of Physical ChemistryJohannes Kepler University Linz (JKU)Altenbergerstrasse 69A-4040LinzAustria
| | - Günther Knör
- Institute of Inorganic ChemistryJohannes Kepler University Linz (JKU)Altenbergerstrasse 69A-4040LinzAustria
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13
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Topf C, Kaiser M, Monkowius U, Knör G. Synthesis and characterisation of heterotrinuclear transition metal complexes for biomimetic proton reduction. INORG CHEM COMMUN 2017. [DOI: 10.1016/j.inoche.2017.01.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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