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Khan MA, Sen UR, Khan S, Sengupta S, Shruti S, Naskar S. Manganese based Molecular Water Oxidation Catalyst: From Natural to Artificial Photosynthesis. COMMENT INORG CHEM 2022. [DOI: 10.1080/02603594.2022.2130273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
| | | | - Sahanwaj Khan
- Department of Chemistry, Birla Institute of Technology-Mesra, Ranchi, India
| | - Swaraj Sengupta
- Department of Chemical Engineering, Birla Institute of Technology-Mesra, Ranchi, India
| | - Sonal Shruti
- Department of Chemistry, Birla Institute of Technology-Mesra, Ranchi, India
| | - Subhendu Naskar
- Department of Chemistry, Birla Institute of Technology-Mesra, Ranchi, India
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Bedin M, Agarwala H, Marx J, Schünemann V, Ott S, Thapper A. Synthesis and properties of a heterobimetallic iron-manganese complex and its comparison with homobimetallic analogues. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2019.03.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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3
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Auvray T, Sahoo R, Deschênes D, Hanan GS. Heteroleptic ruthenium bis-terpyridine complexes bearing a 4-(dimethylamino)phenyl donor and free coordination sites for hydrogen photo-evolution. Dalton Trans 2019; 48:15136-15143. [DOI: 10.1039/c9dt02613d] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Three new ruthenium bis-terpyridine complexes bearing both an internal electron donor and peripheral coordination site(s) are used as photosensitisers in H2 photo-evolution under blue and green light with sustained activity for at least two days.
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Affiliation(s)
- Thomas Auvray
- Département de Chimie
- Université de Montréal
- Montréal
- Canada
| | - Rakesh Sahoo
- Département de Chimie
- Université de Montréal
- Montréal
- Canada
| | | | - Garry S. Hanan
- Département de Chimie
- Université de Montréal
- Montréal
- Canada
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Mede T, Jäger M, Schubert US. "Chemistry-on-the-complex": functional Ru II polypyridyl-type sensitizers as divergent building blocks. Chem Soc Rev 2018; 47:7577-7627. [PMID: 30246196 DOI: 10.1039/c8cs00096d] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Ruthenium polypyridyl type complexes are potent photoactive compounds, and have found - among others - a broad range of important applications in the fields of biomedical diagnosis and phototherapy, energy conversion schemes such as dye-sensitized solar cells (DSSCs) and molecular assemblies for tailored photo-initiated processes. In this regard, the linkage of RuII polypyridyl-type complexes with specific functional moieties is highly desirable to enhance their inherent photophysical properties, e.g., with a targeting function to achieve cell selectivity, or with a dye or redox-active subunits for energy- and electron-transfer. However, the classical approach of performing ligand syntheses first and the formation of Ru complexes in the last steps imposes synthetic limitations with regard to tolerating functional groups or moieties as well as requiring lengthy convergent routes. Alternatively, the diversification of Ru complexes after coordination (termed "chemistry-on-the-complex") provides an elegant complementary approach. In addition to the Click chemistry concept, the rapidly developing synthesis and purification methodologies permit the preparation of Ru conjugates via amidation, alkylation and cross-coupling reactions. In this regard, recent developments in chromatography shifted the limits of purification, e.g., by using new commercialized surface-modified silica gels and automated instrumentation. This review provides detailed insights into applying the "chemistry-on-the-complex" concept, which is believed to stimulate the modular preparation of unpreceded molecular assemblies as well as functional materials based on Ru-based building blocks, including combinatorial approaches.
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Affiliation(s)
- Tina Mede
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstraße 10, 07743 Jena, Germany.
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Affiliation(s)
- Dong Ryeol Whang
- Institute of Physical Chemistry; Johannes Kepler University Linz; Altenbergerstraße 69 4040 Linz Austria
| | - Dogukan Hazar Apaydin
- Institute of Physical Chemistry; Johannes Kepler University Linz; Altenbergerstraße 69 4040 Linz Austria
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Kärkäs MD, Åkermark B. Catalytic Water Oxidation by Ruthenium Complexes Containing Negatively Charged Ligand Frameworks. CHEM REC 2016; 16:940-63. [DOI: 10.1002/tcr.201500254] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Markus D. Kärkäs
- Department of Organic Chemistry; Arrhenius Laboratory, Stockholm University; 106 91 Stockholm Sweden
| | - Björn Åkermark
- Department of Organic Chemistry; Arrhenius Laboratory, Stockholm University; 106 91 Stockholm Sweden
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Yamamoto M, Wang L, Li F, Fukushima T, Tanaka K, Sun L, Imahori H. Visible light-driven water oxidation using a covalently-linked molecular catalyst-sensitizer dyad assembled on a TiO 2 electrode. Chem Sci 2015; 7:1430-1439. [PMID: 29910901 PMCID: PMC5975926 DOI: 10.1039/c5sc03669k] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 11/09/2015] [Indexed: 01/01/2023] Open
Abstract
The combination of porphyrin as a sensitizer and a ruthenium complex as a water oxidation catalyst (WOC) is promising to exploit highly efficient molecular artificial photosynthetic systems. A covalently-linked ruthenium-based WOC-zinc porphyrin (ZnP) sensitizer dyad was assembled on a TiO2 electrode for visible-light driven water oxidation. The water oxidation activity was found to be improved in comparison to the reference systems with the simple combination of the individual WOC and ZnP as well as with ZnP solely, demonstrating the advantage of the covalent linking approach over the non-covalent one. More importantly, via vectorial multi-step electron transfer triggered by visible light, the dye-sensitized photoelectrochemical cell (DSPEC) achieved a broader PEC response in the visible region than DSPECs with conventional ruthenium-based sensitizers. Initial incident photon-to-current efficiencies of 18% at 424 nm and 6.4% at 564 nm were attained under monochromatic illumination and an external bias of -0.2 V vs. NHE. Fast electron transfer from the WOC to the photogenerated radical cation of the sensitizer through the covalent linkage may suppress undesirable charge recombination, realizing the moderate performance of water oxidation. X-ray photoelectron spectroscopic analysis of the photoanodes before and after the DSPEC operation suggested that most of the ruthenium species exist at higher oxidation states, implying that the insufficient oxidation potential of the ZnP moiety for further oxidizing the intermediate ruthenium species at the photoanode is at least the bottleneck of the system.
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Affiliation(s)
- Masanori Yamamoto
- Department of Molecular Engineering , Graduate School of Engineering , Kyoto University , Nishikyo-ku , Kyoto 615-8510 , Japan .
| | - Lei Wang
- Department of Chemistry , School of Chemical Science and Engineering , KTH Royal Institute of Technology , 100 44 Stockholm , Sweden .
| | - Fusheng Li
- Department of Chemistry , School of Chemical Science and Engineering , KTH Royal Institute of Technology , 100 44 Stockholm , Sweden .
| | - Takashi Fukushima
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS) , Kyoto University , Nishikyo-ku , Kyoto 615-8510 , Japan
| | - Koji Tanaka
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS) , Kyoto University , Nishikyo-ku , Kyoto 615-8510 , Japan
| | - Licheng Sun
- Department of Chemistry , School of Chemical Science and Engineering , KTH Royal Institute of Technology , 100 44 Stockholm , Sweden .
| | - Hiroshi Imahori
- Department of Molecular Engineering , Graduate School of Engineering , Kyoto University , Nishikyo-ku , Kyoto 615-8510 , Japan . .,Institute for Integrated Cell-Material Sciences (WPI-iCeMS) , Kyoto University , Nishikyo-ku , Kyoto 615-8510 , Japan
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Migliore A, Polizzi NF, Therien M, Beratan DN. Biochemistry and theory of proton-coupled electron transfer. Chem Rev 2014; 114:3381-465. [PMID: 24684625 PMCID: PMC4317057 DOI: 10.1021/cr4006654] [Citation(s) in RCA: 354] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Indexed: 02/01/2023]
Affiliation(s)
- Agostino Migliore
- Department
of Chemistry, Department of Biochemistry, and Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - Nicholas F. Polizzi
- Department
of Chemistry, Department of Biochemistry, and Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - Michael
J. Therien
- Department
of Chemistry, Department of Biochemistry, and Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - David N. Beratan
- Department
of Chemistry, Department of Biochemistry, and Department of Physics, Duke University, Durham, North Carolina 27708, United States
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9
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Synthesis and Electron-Transfer Processes in a New Family of Ligands for Coupled Ru−Mn2Complexes. Chempluschem 2014. [DOI: 10.1002/cplu.201402006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Kärkäs MD, Johnston EV, Verho O, Åkermark B. Artificial photosynthesis: from nanosecond electron transfer to catalytic water oxidation. Acc Chem Res 2014; 47:100-11. [PMID: 23957573 DOI: 10.1021/ar400076j] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Human society faces a fundamental challenge as energy consumption is projected to increase due to population and economic growth as fossil fuel resources decrease. Therefore the transition to alternative and sustainable energy sources is of the utmost importance. The conversion of solar energy into chemical energy, by splitting H2O to generate molecular O2 and H2, could contribute to solving the global energy problem. Developing such a system will require the combination of several complicated processes, such as light-harvesting, charge separation, electron transfer, H2O oxidation, and reduction of the generated protons. The primary processes of charge separation and catalysis, which occur in the natural photosynthetic machinery, provide us with an excellent blueprint for the design of such systems. This Account describes our efforts to construct supramolecular assemblies capable of carrying out photoinduced electron transfer and to develop artificial water oxidation catalysts (WOCs). Early work in our group focused on linking a ruthenium chromophore to a manganese-based oxidation catalyst. When we incorporated a tyrosine unit into these supramolecular assemblies, we could observe fast intramolecular electron transfer from the manganese centers, via the tyrosine moiety, to the photooxidized ruthenium center, which clearly resembles the processes occurring in the natural system. Although we demonstrated multi-electron transfer in our artificial systems, the bottleneck proved to be the stability of the WOCs. Researchers have developed a number of WOCs, but the majority can only catalyze H2O oxidation in the presence of strong oxidants such as Ce(IV), which is difficult to generate photochemically. By contrast, illumination of ruthenium(II) photosensitizers in the presence of a sacrificial acceptor generates [Ru(bpy)3](3+)-type oxidants. Their oxidation potentials are significantly lower than that of Ce(IV), but our group recently showed that incorporating negatively charged groups into the ligand backbone could decrease the oxidation potential of the catalysts and, at the same time, decrease the potential for H2O oxidation. This permitted us to develop both ruthenium- and manganese-based WOCs that can operate under neutral conditions, driven by the mild oxidant [Ru(bpy)3](3+). Many hurdles to the development of viable systems for the production of solar fuels remain. However, the combination of important features from the natural photosynthetic machinery and novel artificial components adds insights into the complicated catalytic processes that are involved in splitting H2O.
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Affiliation(s)
- Markus D. Kärkäs
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Eric V. Johnston
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Oscar Verho
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Björn Åkermark
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
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11
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López AM, Natali M, Pizzolato E, Chiorboli C, Bonchio M, Sartorel A, Scandola F. A Co(ii)–Ru(ii) dyad relevant to light-driven water oxidation catalysis. Phys Chem Chem Phys 2014; 16:12000-7. [DOI: 10.1039/c3cp55369h] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The covalent anchoring of a Co(ii) water oxidation catalyst to a Ru(ii) photosensitizer with potential application in artificial photosynthesis.
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Affiliation(s)
| | - Mirco Natali
- Department of Chemical and Pharmaceutical Sciences
- University of Ferrara, and Centro Interuniversitario per la Conversione Chimica dell'Energia Solare (sez. Ferrara)
- 44121 Ferrara, Italy
| | - Erica Pizzolato
- ITM-CNR and Department of Chemical Sciences
- University of Padova
- 35131 Padova, Italy
| | - Claudio Chiorboli
- ISOF-CNR c/o Department of Chemical and Pharmaceutical Sciences
- University of Ferrara
- 44121 Ferrara, Italy
| | - Marcella Bonchio
- ITM-CNR and Department of Chemical Sciences
- University of Padova
- 35131 Padova, Italy
| | - Andrea Sartorel
- ITM-CNR and Department of Chemical Sciences
- University of Padova
- 35131 Padova, Italy
| | - Franco Scandola
- Department of Chemical and Pharmaceutical Sciences
- University of Ferrara, and Centro Interuniversitario per la Conversione Chimica dell'Energia Solare (sez. Ferrara)
- 44121 Ferrara, Italy
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Chakrabarty PP, Saha S, Schollmeyer D, Boudalis AK, Jana AD, Luneau D. Azide-bridged manganese(III) one-dimensional chain: synthesis, structure, and magnetic study. J COORD CHEM 2012. [DOI: 10.1080/00958972.2012.744971] [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]
Affiliation(s)
| | - Sandip Saha
- a Department of Chemistry , Acharya Prafulla Chandra College , Kolkata , India
| | | | | | | | - Dominique Luneau
- e Université Claude Bernard Lyon 1 Groupe de Cristallographie et Ingénierie Moléculaire Laboratoire des Multimatériaux et Interfaces (UMR 5615) Bâtiment Berthollet – Domaine Scientifique de la Doua 69622 , Villeurbanne Cedex , France
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Young KJ, Martini LA, Milot RL, III RCS, Batista VS, Schmuttenmaer CA, Crabtree RH, Brudvig GW. Light-driven water oxidation for solar fuels. Coord Chem Rev 2012; 256:2503-2520. [PMID: 25364029 PMCID: PMC4214930 DOI: 10.1016/j.ccr.2012.03.031] [Citation(s) in RCA: 238] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Light-driven water oxidation is an essential step for conversion of sunlight into storable chemical fuels. Fujishima and Honda reported the first example of photoelectrochemical water oxidation in 1972. In their system, TiO2 was irradiated with ultraviolet light, producing oxygen at the anode and hydrogen at a platinum cathode. Inspired by this system, more recent work has focused on functionalizing nanoporous TiO2 or other semiconductor surfaces with molecular adsorbates, including chromophores and catalysts that absorb visible light and generate electricity (i.e., dye-sensitized solar cells) or trigger water oxidation at low overpotentials (i.e., photocatalytic cells). The physics involved in harnessing multiple photochemical events for multielectron reactions, as required in the four-electron water oxidation process, has been the subject of much experimental and computational study. In spite of significant advances with regard to individual components, the development of highly efficient photocatalytic cells for solar water splitting remains an outstanding challenge. This article reviews recent progress in the field with emphasis on water-oxidation photoanodes inspired by the design of functionalized thin film semiconductors of typical dye-sensitized solar cells.
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Affiliation(s)
- Karin J. Young
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520-8107, USA
| | - Lauren A. Martini
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520-8107, USA
| | - Rebecca L. Milot
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520-8107, USA
| | | | - Victor S. Batista
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520-8107, USA
| | | | - Robert H. Crabtree
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520-8107, USA
| | - Gary W. Brudvig
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520-8107, USA
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14
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Molecular devices featuring sequential photoinduced charge separations for the storage of multiple redox equivalents. Coord Chem Rev 2011. [DOI: 10.1016/j.ccr.2010.12.017] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Bonin J, Robert M. Photoinduced Proton-Coupled Electron Transfers in Biorelevant Phenolic Systems. Photochem Photobiol 2011; 87:1190-203. [DOI: 10.1111/j.1751-1097.2011.00996.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Grundmeier A, Dau H. Structural models of the manganese complex of photosystem II and mechanistic implications. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1817:88-105. [PMID: 21787743 DOI: 10.1016/j.bbabio.2011.07.004] [Citation(s) in RCA: 191] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 07/06/2011] [Accepted: 07/08/2011] [Indexed: 11/29/2022]
Abstract
Photosynthetic water oxidation and O₂ formation are catalyzed by a Mn₄Ca complex bound to the proteins of photosystem II (PSII). The catalytic site, including the inorganic Mn₄CaO(n)H(x) core and its protein environment, is denoted as oxygen-evolving complex (OEC). Earlier and recent progress in the endeavor to elucidate the structure of the OEC is reviewed, with focus on recent results obtained by (i) X−ray spectroscopy (specifically by EXAFS analyses), and (ii) X-ray diffraction (XRD, protein crystallography). Very recently, an impressive resolution of 1.9Å has been achieved by XRD. Most likely however, all XRD data on the Mn₄CaO(n)H(x) core of the OEC are affected by X-ray induced modifications (radiation damage). Therefore and to address (important) details of the geometric and electronic structure of the OEC, a combined analysis of XRD and XAS data has been approached by several research groups. These efforts are reviewed and extended using an especially comprehensive approach. Taking into account XRD results on the protein environment of the inorganic core of the Mn complex, 12 alternative OEC models are considered and evaluated by quantitative comparison to (i) extended-range EXAFS data, (ii) polarized EXAFS of partially oriented PSII membrane particles, and (iii) polarized EXAFS of PSII crystals. We conclude that there is a class of OEC models that is in good agreement with both the recent crystallographic models and the XAS data. On these grounds, mechanistic implications for the O−O bond formation chemistry are discussed. This article is part of a Special Issue entitled: Photosystem II.
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Bhowmik P, Nayek HP, Corbella M, Aliaga-Alcalde N, Chattopadhyay S. Control of molecular architecture by steric factors: mononuclear vs polynuclear manganese(iii) compounds with tetradentate N2O2 donor Schiff bases. Dalton Trans 2011; 40:7916-26. [DOI: 10.1039/c0dt01723j] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Affiliation(s)
- Jillian L. Dempsey
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125
| | - Jay R. Winkler
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125
| | - Harry B. Gray
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125
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Collomb M, Deronzier A. Electro‐ and Photoinduced Formation and Transformation of Oxido‐Bridged Multinuclear Mn Complexes. Eur J Inorg Chem 2009. [DOI: 10.1002/ejic.200801141] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Marie‐Noëlle Collomb
- Université Joseph Fourier Grenoble 1/CNRS, Département de Chimie Moléculaire, UMR‐5250, Institut de Chimie Moléculaire de Grenoble FR‐CNRS‐2607, Laboratoire de Chimie Inorganique Redox B. P. 53, 38041 Grenoble Cedex 9, France
| | - Alain Deronzier
- Université Joseph Fourier Grenoble 1/CNRS, Département de Chimie Moléculaire, UMR‐5250, Institut de Chimie Moléculaire de Grenoble FR‐CNRS‐2607, Laboratoire de Chimie Inorganique Redox B. P. 53, 38041 Grenoble Cedex 9, France
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Weare WW, Pushkar Y, Yachandra VK, Frei H. Visible Light-Induced Electron Transfer from Di-μ-oxo-Bridged Dinuclear Mn Complexes to Cr Centers in Silica Nanopores. J Am Chem Soc 2008; 130:11355-63. [DOI: 10.1021/ja801546a] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Walter W. Weare
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720
| | - Yulia Pushkar
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720
| | - Vittal K. Yachandra
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720
| | - Heinz Frei
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720
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Hammarström L, Styring S. Coupled electron transfers in artificial photosynthesis. Philos Trans R Soc Lond B Biol Sci 2008; 363:1283-91; discussion 1291. [PMID: 17954432 DOI: 10.1098/rstb.2007.2225] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Light-induced charge separation in molecular assemblies has been widely investigated in the context of artificial photosynthesis. Important progress has been made in the fundamental understanding of electron and energy transfer and in stabilizing charge separation by multi-step electron transfer. In the Swedish Consortium for Artificial Photosynthesis, we build on principles from the natural enzyme photosystem II and Fe-hydrogenases. An important theme in this biomimetic effort is that of coupled electron-transfer reactions, which have so far received only little attention. (i) Each absorbed photon leads to charge separation on a single-electron level only, while catalytic water splitting and hydrogen production are multi-electron processes; thus there is the need for controlling accumulative electron transfer on molecular components. (ii) Water splitting and proton reduction at the potential catalysts necessarily require the management of proton release and/or uptake. Far from being just a stoichiometric requirement, this controls the electron transfer processes by proton-coupled electron transfer (PCET). (iii) Redox-active links between the photosensitizers and the catalysts are required to rectify the accumulative electron-transfer reactions, and will often be the starting points of PCET.
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Affiliation(s)
- Leif Hammarström
- Department of Photochemistry and Molecular Science, Uppsala University, PO Box 523, 751 20 Uppsala, Sweden.
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Abstract
Energy is the most important issue of the 21st century. About 85% of our energy comes from fossil fuels, a finite resource unevenly distributed beneath the Earth's surface. Reserves of fossil fuels are progressively decreasing, and their continued use produces harmful effects such as pollution that threatens human health and greenhouse gases associated with global warming. Prompt global action to solve the energy crisis is therefore needed. To pursue such an action, we are urged to save energy and to use energy in more efficient ways, but we are also forced to find alternative energy sources, the most convenient of which is solar energy for several reasons. The sun continuously provides the Earth with a huge amount of energy, fairly distributed all over the world. Its enormous potential as a clean, abundant, and economical energy source, however, cannot be exploited unless it is converted into useful forms of energy. This Review starts with a brief description of the mechanism at the basis of the natural photosynthesis and, then, reports the results obtained so far in the field of photochemical conversion of solar energy. The "grand challenge" for chemists is to find a convenient means for artificial conversion of solar energy into fuels. If chemists succeed to create an artificial photosynthetic process, "... life and civilization will continue as long as the sun shines!", as the Italian scientist Giacomo Ciamician forecast almost one hundred years ago.
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Affiliation(s)
- Vincenzo Balzani
- Dipartimento di Chimica "G. Ciamician", Università di Bologna, Via Selmi 2 40126 Bologna, Italy.
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Romain S, Leprêtre JC, Chauvin J, Deronzier A, Collomb MN. Di(μ-oxo) Binuclear Manganese(III,IV) Poly(bipyridyl) Complexes Bearing Four Ruthenium(II) Photoactive Units: Synthesis, Characterization, and Photoinduced Electron-Transfer Properties. Inorg Chem 2007; 46:2735-43. [PMID: 17295479 DOI: 10.1021/ic0624726] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In order to model the photoinduced electron-transfer reactions from the manganese cluster to the photoactive P680 chlorophylls in photosystem II, three heterohexanuclear complexes, [Mn2III,IVO2[RuII(bpy)2(Ln)]4]11+ [bpy = 2,2'-bipyridine, n = 2 (1a), 4 (1b), 6 (1c)], in which one MnIII,IV(micro-O)2 center is covalently linked to four RuII(bpy)3-like moieties by bridged bis(bipyridine) Ln ligands, have been synthesized and characterized. The electrochemical, photophysical, and photochemical properties of these complexes have been investigated in CH3CN. The cyclic voltammograms and rotating-disk electrode curves of the three complexes show the presence of two very close successive reversible oxidation processes corresponding to the Mn2III,IV/Mn2IV,IV and RuII/RuIII redox couples (estimated E1/2 approximately 0.82 and 0.90 V, respectively). The lower potential of the Mn2III,IV subunit compared to those of the RuII moieties indicates that the RuIII species can act as an efficient oxidant toward the Mn2III,IV core. The two oxidized forms of the complexes [Mn2IV,IVO2[RuII(bpy)2(Ln)]4]12+ (2a-c) and [Mn2IV,IVO2[RuIII(bpy)2(Ln)]4]16+ (3a-c) obtained in good yields (>90% for 2a-c and >85% for 3a-c) by sequential electrolyses are very stable. Photophysical studies show that the 3MLCT excited state of the Ru(bpy)3 centers is moderately quenched by the Mn2III,IV(micro-O)2 core (15-25% depending on the length of the bridging alkyl chain). Nevertheless, this energy transfer can be easily short-circuited in the presence of an external irreversible electron acceptor like the (4-bromophenyl)diazonium cation, by an electron transfer leading, in a stepwise fashion, to the stable one- and five-electron-oxidized species 2a-c and 3a-c, respectively, also in good yields, under continuous irradiation of the solutions. Electro- and photoinduced oxidation experiments have been followed by UV-visible and electron paramagnetic resonance spectroscopy.
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Affiliation(s)
- Sophie Romain
- Laboratoire d'Electrochimie Organique et de Photochimie Rédox, Université Joseph Fourier, UMR CNRS 5630, Institut de Chimie Moléculaire de Grenoble, FR CNRS 2607, BP 53, 38041 Grenoble Cedex 9, France
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Kurz P, Berggren G, Anderlund MF, Styring S. Oxygen evolving reactions catalysed by synthetic manganese complexes: A systematic screening. Dalton Trans 2007:4258-61. [PMID: 17893814 DOI: 10.1039/b710761g] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A set of six multinuclear manganese complexes was screened for the ability to catalyse reactions yielding O(2) under coherent experimental conditions; we identify a much larger number of manganese compounds than previously known that catalyse oxygen formation.
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Affiliation(s)
- Philipp Kurz
- Department of Photochemistry and Molecular Science, Angström laboratory, Uppsala University, Box 523, S-75120, Uppsala, Sweden
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Anderlund MF, Zheng J, Ghiladi M, Kritikos M, Rivière E, Sun L, Girerd JJ, Åkermark B. A new, dinuclear high spin manganese(III) complex with bridging phenoxy and methoxy groups. Structure and magnetic properties. INORG CHEM COMMUN 2006. [DOI: 10.1016/j.inoche.2006.07.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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26
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Anderlund MF, Högblom J, Shi W, Huang P, Eriksson L, Weihe H, Styring S, Åkermark B, Lomoth R, Magnuson A. Redox Chemistry of a Dimanganese(II,III) Complex with an Unsymmetric Ligand: Water Binding, Deprotonation and Accumulative Light-Induced Oxidation. Eur J Inorg Chem 2006. [DOI: 10.1002/ejic.200600676] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Zettersten C, Lomoth R, Hammarström L, Sjöberg PJ, Nyholm L. The influence of the thin-layer flow cell design on the mass spectra when coupling electrochemistry to electrospray ionisation mass spectrometry. J Electroanal Chem (Lausanne) 2006. [DOI: 10.1016/j.jelechem.2006.02.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Huang P, Anderlund M, Weihe H, Barra AL, Sun L. Sign of excited spin state magnetic anisotropy parameters. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2006; 63:541-3. [PMID: 16024278 DOI: 10.1016/j.saa.2005.05.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2004] [Revised: 05/27/2005] [Accepted: 05/29/2005] [Indexed: 05/03/2023]
Abstract
By using high frequency high field EPR spectroscopy we demonstrate how to extract the sign of magnetic anisotropy parameters pertinent to excited spin multiplets of antiferromagnetically coupled clusters. The method is demonstrated on a manganese(II) dimer.
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Affiliation(s)
- Ping Huang
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
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Lomoth R, Magnuson A, Sjödin M, Huang P, Styring S, Hammarström L. Mimicking the electron donor side of Photosystem II in artificial photosynthesis. PHOTOSYNTHESIS RESEARCH 2006; 87:25-40. [PMID: 16416050 DOI: 10.1007/s11120-005-9005-0] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2005] [Accepted: 06/24/2005] [Indexed: 05/06/2023]
Abstract
This review focuses on our recent efforts in synthetic ruthenium-tyrosine-manganese chemistry mimicking the donor side reactions of Photosystem II. Tyrosine and tryptophan residues were linked to ruthenium photosensitizers, which resulted in model complexes for proton-coupled electron transfer from amino acids. A new mechanistic model was proposed and used to design complexes in which the mechanism could be switched between concerted and step-wise proton-coupled electron transfer. Moreover, a manganese dimer linked to a ruthenium complex could be oxidized in three successive steps, from Mn (2) (II,II) to Mn (2) (III,IV) by the photo-oxidized ruthenium sensitizer. This was possible thanks to a charge compensating ligand exchange in the manganese complex. Detailed studies of the ligand exchange suggested that at high water concentrations, each oxidation step is coupled to a proton-release of water-derived ligands, analogous to the oxidation steps of the manganese cluster of Photosystem II.
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Affiliation(s)
- Reiner Lomoth
- Department of Physical Chemistry, Uppsala University, Box 579, 751 23 Uppsala, Sweden
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30
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Romain S, Baffert C, Dumas S, Chauvin J, Leprêtre JC, Daveloose D, Deronzier A, Collomb MN. Tetranuclear polybipyridyl complexes of RuIIand MnII, their electro- and photo-induced transformation into di-µ-oxo MnIIIMnIVhexanuclear complexes. Dalton Trans 2006:5691-702. [PMID: 17146534 DOI: 10.1039/b610728a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three heterotetranuclear complexes, [{Ru(II)(bpy)(2)(L(n))}(3)Mn(II)](8+) (bpy = 2,2'-bipyridine, n = 2, 4, 6), in which a Mn(II)-tris-bipyridine-like centre is covalently linked to three Ru(II)-tris-bipyridine-like moieties using bridging bis-bipyridine L(n) ligands, have been synthesised and characterised. The electrochemical, photophysical and photochemical properties of these complexes have been investigated in CH(3)CN. The cyclic voltammograms of the three complexes exhibit two successive very close one-electron metal-centred oxidation processes in the positive potential region. The first, which is irreversible, corresponds to the Mn(II)/Mn(III) redox system (E(pa) approximately 0.82 V vs Ag/Ag(+) 0.01 M in CH(3)CN-0.1 M Bu(4)NClO(4)), whereas the second which is, reversible, is associated with the Ru(II)/Ru(III) redox couple (E(1/2) approximately 0.91 V). In the negative potential region, three successive reversible four electron systems are observed, corresponding to ligand-based reduction processes. The three stable dimeric oxidized forms of the complexes, [Mn(2)(III,IV)O(2){Ru(II)(bpy)(2)(L(n))}(4)](11+), [Mn(2)(IV,IV)O(2){Ru(II)(bpy)(2)(L(n))}(4)](12+) and [Mn(2)(IV,IV)O(2){Ru(III)(bpy)(2)(L(n))}(4)](16+) are obtained in fairly good yields by sequential electrolyses after consumption of respectively 1.5, 0.5 and 3 electrons per molecule of initial tetranuclear complexes. The formation of the di-micro-oxo binuclear complexes are the result of the instability of the {[Ru(II)(bpy)(2)(L(n))](3)Mn(III)}(9+) species, which react with residual water, via a disproportionation reaction and the release of one ligand, [Ru(II)(bpy)(2)(L(n))](2+). A quantitative yield can be obtained for these reactions if the electrochemical oxidations are performed in the presence of an added external base like 2,6-dimethylpyridine. Photophysical properties of these compounds have been investigated showing that the luminescence of the Ru(II)-tris-bipyridine-like moieties is little affected by the presence of manganese within the tetranuclear complexes. A slight quenching of the excited states of the ruthenium moieties, which occurs by an intramolecular process, has been observed. Measurements made at low concentration (<1 x 10(-5) M) indicate that some decoordination of Mn(2+) arises in 1a-c. These measurements allow the calculation of the association constants for these complexes. Finally, photoinduced oxidation of the tetranuclear complexes has been performed by continuous photolysis experiments in the presence of a large excess of a diazonium salt, acting as a sacrificial oxidant. The three successive oxidation processes, Mn(II)--> Mn(III)Mn(IV), Mn(III)Mn(IV)--> Mn(IV)Mn(IV) and Ru(II)--> Ru(III) are thus obtained, the addition of 2,6-dimethylpyridine in the medium giving an essentially quantitative yield for the two first photo-induced oxidation steps as found for electrochemical oxidation.
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Affiliation(s)
- Sophie Romain
- Laboratoire d'Electrochimie Organique et de Photochimie Rédox, Université Joseph Fourier, UMR CNRS 5630, Institut de Chimie Moléculaire de Grenoble, FR CNRS 2607, BP 53, 38041, Grenoble Cedex 9, France
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Xu Y, Eilers G, Borgström M, Pan J, Abrahamsson M, Magnuson A, Lomoth R, Bergquist J, Polívka T, Sun L, Sundström V, Styring S, Hammarström L, Akermark B. Synthesis and Characterization of Dinuclear Ruthenium Complexes Covalently Linked to RuII Tris-bipyridine: An Approach to Mimics of the Donor Side of Photosystem II. Chemistry 2005; 11:7305-14. [PMID: 16163754 DOI: 10.1002/chem.200500592] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
To mimic the electron-donor side of photosystem II (PSII), three trinuclear ruthenium complexes (2, 2a, 2b) were synthesized. In these complexes, a mixed-valent dinuclear Ru2(II,III) moiety with one phenoxy and two acetato bridges is covalently linked to a Ru(II) tris-bipyridine photosensitizer. The properties and photoinduced electron/energy transfer of these complexes were studied. The results show that the Ru2(II,III) moieties in the complexes readily undergo reversible one-electron reduction and one-electron oxidation to give the Ru2(II,III) and Ru2(III,III) states, respectively. This could allow for photooxidation of the sensitizer part with an external acceptor and subsequent electron transfer from the dinuclear ruthenium moiety to regenerate the sensitizer. However, all trinuclear ruthenium complexes have a very short excited-state lifetime, in the range of a few nanoseconds to less than 100 ps. Studies by femtosecond time-resolved techniques suggest that a mixture of intramolecular energy and electron transfer between the dinuclear ruthenium moiety and the excited [Ru(bpy)3]2+ photosensitizer is responsible for the short lifetimes. This problem is overcome by anchoring the complexes with ester- or carboxyl-substituted bipyridine ligands (2a, 2b) to nanocrystalline TiO2, and the desired electron transfer from the excited state of the [Ru(bpy)3]2+ moiety to the conduction band of TiO2 followed by intramolecular electron transfer from the dinuclear Ru2(II,III) moiety to photogenerated Ru(III) was observed. The resulting long-lived Ru2(III,III) state decays on the millisecond timescale.
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Affiliation(s)
- Yunhua Xu
- Department of Organic Chemistry, Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
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Baffert C, Dumas S, Chauvin J, Leprêtre JC, Collomb MN, Deronzier A. Photoinduced oxidation of [Mn(L)3]2+and [Mn2O2(L)4]3+ (L = 2,2′-bipyridine and 4,4′-dimethyl-2,2′-bipyridine) with the [Ru(bpy)3]2+/-aryl diazonium salt system. Phys Chem Chem Phys 2005. [DOI: 10.1039/b411365a] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Eilers G, Zettersten C, Nyholm L, Hammarström L, Lomoth R. Ligand exchange upon oxidation of a dinuclear Mn complex–detection of structural changes by FT-IR spectroscopy and ESI-MS. Dalton Trans 2005:1033-41. [PMID: 15739005 DOI: 10.1039/b415148h] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The structural rearrangements triggered by oxidation of the dinuclear Mn complex [Mn(2)(bpmp)(mu-OAc)2]+(bpmp = 2,6-bis[bis(2-pyridylmethyl)amino]methyl-4-methylphenol anion) in the presence of water have been studied by combinations of electrochemistry with IR spectroscopy and with electrospray ionization mass spectrometry (ESI-MS). The exchange of acetate bridges for water (D2O) derived ligands in different oxidation states could be monitored by mid-IR spectroscopy in CD(3)CN-D(2)O mixtures following the v(as(C-O)) bands of bound acetate at 1594.4 cm(-1)(II,II), 1592.0 cm(-1)(II,III) and 1586.5 cm(-1)(III,III). Substantial loss of bound acetate occurs at much lower water content (< 0.5% v/v) in the III,III state than in the II,II and II,III states (> or = 10%). The ligand-exchange reactions do not initially reduce the overall charge of the complex but facilitate further oxidation by proton-coupled electron transfer as the water-derived ligands are increasingly deprotonated in higher oxidation states. In the IR spectra deprotonation could be followed by the formation of acetic acid (DOAc, approximately 1725 cm(-1), v(C-O)) from the released acetate (1573.6 cm(-1), v(as(C-O))). By the on-line combination of an electrochemical flow cell with ESI-MS several product complexes could be identified. A di-mu-oxo bridged III,IV dimer [Mn(2)(bpmp)(mu-O)(2)](2+)(m/z 335.8) can be generated at potentials below the III,III/II,III couple of the di-mu-acetato complex (0.61 V vs. ferrocene). The ligand-exchange reactions allow for three metal-centered oxidation steps to occur from II,II to III,IV in a potential range of only 0.5 V, explaining the formation of a spin-coupled III,IV dimer by photo-oxidation with [Ru[bpy)(3)](3+) in previous EPR studies.
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Affiliation(s)
- Gerriet Eilers
- Department of Physical Chemistry, Uppsala University, Box 579, S-75123 Uppsala, Sweden
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Wolpher H, Huang P, Borgström M, Bergquist J, Styring S, Sun L, Åkermark B. Synthesis of a Ru(bpy)3-type complex linked to a free terpyridine ligand and its use for preparation of polynuclear bimetallic complexes. Catal Today 2004. [DOI: 10.1016/j.cattod.2004.09.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Huang P, Högblom J, Anderlund MF, Sun L, Magnuson A, Styring S. Light-induced multistep oxidation of dinuclear manganese complexes for artificial photosynthesis. J Inorg Biochem 2004; 98:733-45. [PMID: 15134919 DOI: 10.1016/j.jinorgbio.2003.12.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2003] [Revised: 12/10/2003] [Accepted: 12/11/2003] [Indexed: 11/22/2022]
Abstract
Two dinuclear manganese complexes, [Mn(2)BPMP(mu-OAc)(2)].ClO(4) (1, where BPMP is the anion of 2,6-bis([N,N-di(2-pyridinemethyl)amino]methyl)-4-methylphenol) and [Mn(2)L(mu-OAc)(2)].ClO(4) (2, where L is the trianion of 2,6-bis([N-(2-hydroxy-3,5-di-tert-butylbenzyl)-N-(2-pyridinemethyl)amino]methyl)-4-methylphenol), undergo several oxidations by laser flash photolysis, using ruthenium(II)-tris-bipyridine (tris(2,2-bipyridyl)dichloro-ruthenium(II) hexahydrate) as photo-sensitizer and penta-amminechlorocobalt(III) chloride as external electron acceptor. In both complexes stepwise electron transfer was observed. In 1, four Mn-valence states from the initial Mn(2)(II,II) to the Mn(2)(III,IV) state are available. In 2, three oxidation steps are possible from the initial Mn(2)(III,III)state. The last step is accomplished in the Mn(2)(IV,IV) state, which results in a phenolate radical. For the first time we provide firm spectral evidence for formation of the first intermediate state, Mn(2)(II,III), in 1 during the stepwise light-induced oxidation. Observation of Mn(2)(II,III) is dependent on conditions that sustain the mu-acetato bridges in the complex, i.e., by forming Mn(2)(II,III) in dry acetonitrile, or by addition of high concentrations of acetate in aqueous solutions. We maintain that the presence of water is necessary for the transition to higher oxidation states, e.g., Mn(2)(III,III) and Mn(2)(III,IV) in 1, due to a bridging ligand exchange reaction which takes place in the Mn(2)(II,III) state in water solution. Water is also found to be necessary for reaching the Mn(2)(IV,IV) state in 2, which explains why this state was not reached by electrolysis in our earlier work (Eur. J. Inorg. Chem (2002) 2965). In 2, the extra coordinating oxygen atoms facilitate the stabilization of higher Mn valence states than in 1, resulting in formation of a stable Mn(2)(IV,IV) without disintegration of 2. In addition, further oxidation of 2, led to the formation of a phenolate radical (g = 2.0046) due to ligand oxidation. Its spectral width (8 mT) and very fast relaxation at 15 K indicates that this radical is magnetically coupled to the Mn(2)(IV,IV) center.
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Affiliation(s)
- Ping Huang
- Department of Biochemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, Lund S-22100, Sweden
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Chen C, Huang D, Zhang X, Chen F, Zhu H, Liu Q, Zhang C, Liao D, Li L, Sun L. Aggregate manganese Schiff base moieties by terephthalate or acetate: dinuclear manganese and trinuclear mixed metal Mn2/Na complexes. Inorg Chem 2003; 42:3540-8. [PMID: 12767191 DOI: 10.1021/ic025944z] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A reaction system consisting of terephthalic acid, NaOH, inorganic Mn(II) or Mn(III) salt, and salicylidene alkylimine resulted in dinuclear manganese complexes (salpn)(2)Mn(2)(mu-phth)(CH(3)OH)(2) (1, salpn = N,N'-1,3-propylene-bis(salicylideneiminato); phth = terephthalate dianion), (salen)(2)Mn(2)(mu-phth)(CH(3)OH)(2) (2, salen = N,N'-ethylene-bis(salicylideneiminato)), (salen)(2)Mn(2)(mu-phth)(CH(3)OH)(H(2)O) (3), and (salen)(2)Mn(2)(mu-phth) (4), while the absence of NaOH in the reaction led to a mononuclear Mn complex (salph)Mn(CH(3)OH)(NO(3)) (5, salph = N,N'-1,2-phenylene-bis(salicylideneiminato)). In addition, a trinuclear mixed metal complex H[Mn(2)Na(salpn)(2)(mu-OAc)(2)(H(2)O)(2)](OAc)(2) (6) was obtained from the reaction system by using maleic acid instead of terephthalic acid. Five-coordinate Mn ions were found in 4 giving rise to an intermolecular interaction and constructing a one-dimensional linear structure. Antiferromagnetic exchange interactions were observed for 1-3, and a total ferromagnetic exchange of 4 was considered to stem from intermolecular magnetic coupling. (1)H NMR signals of phenolate ring and alkylene (or phenylene) backbone of the diamine are similar to those reported in the literature, and the phth protons are at -2.3 to -10.1 ppm. Studies on structure, bond valence sum analysis, and magnetic properties indicate the oxidation states of the Mn ions in 6 to be +3, which are also indicated by ESR spectra in dual mode. Ferromagnetic exchange interaction between the Mn(III) sites was observed with J = 1.74 cm(-1). A quasireversible redox pair at -0.29V/-0.12V has been assigned to the redox of Mn(2)(III)/Mn(III)Mn(II), implying the intactness of the complex backbone in solution.
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Affiliation(s)
- Changneng Chen
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
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Huang P, Magnuson A, Lomoth R, Abrahamsson M, Tamm M, Sun L, van Rotterdam B, Park J, Hammarström L, Akermark B, Styring S. Photo-induced oxidation of a dinuclear Mn(2)(II,II) complex to the Mn(2)(III,IV) state by inter- and intramolecular electron transfer to Ru(III)tris-bipyridine. J Inorg Biochem 2002; 91:159-72. [PMID: 12121773 DOI: 10.1016/s0162-0134(02)00394-x] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
To model the structural and functional parts of the water oxidizing complex in Photosystem II, a dimeric manganese(II,II) complex (1) was linked to a ruthenium(II)tris-bipyridine (Ru(II)(bpy)(3)) complex via a substituted L-tyrosine, to form the trinuclear complex 2 [J. Inorg. Biochem. 78 (2000) 15]. Flash photolysis of 1 and Ru(II)(bpy)(3) in aqueous solution, in the presence of an electron acceptor, resulted in the stepwise extraction of three electrons by Ru(III)(bpy)(3) from the Mn(2)(II,II) dimer, which then attained the Mn(2)(III,IV) oxidation state. In a similar experiment with compound 2, the dinuclear Mn complex reduced the photo-oxidized Ru moiety via intramolecular electron transfer on each photochemical event. From EPR it was seen that 2 also reached the Mn(2)(III,IV) state. Our data indicate that oxidation from the Mn(2)(II,II) state proceeds stepwise via intermediate formation of Mn(2)(II,III) and Mn(2)(III,III). In the presence of water, cyclic voltammetry showed an additional anodic peak beyond Mn(2)(II,III/III,III) oxidation which was significantly lower than in neat acetonitrile. Assuming that this peak is due to oxidation to Mn(2)(III,IV), this suggests that water is essential for the formation of the Mn(2)(III,IV) oxidation state. Compound 2 is a structural mimic of the water oxidizing complex, in that it links a Mn complex via a tyrosine to a highly oxidizing photosensitizer. Complex 2 also mimics mechanistic aspects of Photosystem II, in that the electron transfer to the photosensitizer is fast and results in several electron extractions from the Mn moiety.
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Affiliation(s)
- P Huang
- Department of Biochemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, S-221 00 Lund, Sweden
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Abrahamsson MLA, Baudin HB, Tran A, Philouze C, Berg KE, Raymond-Johansson MK, Sun L, Akermark B, Styring S, Hammarstrom L. Ruthenium-manganese complexes for artificial photosynthesis: factors controlling intramolecular electron transfer and excited-state quenching reactions. Inorg Chem 2002; 41:1534-44. [PMID: 11896722 DOI: 10.1021/ic0107227] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Continuing our work toward a system mimicking the electron-transfer steps from manganese to P(680)(+) in photosystem II (PS II), we report a series of ruthenium(II)-manganese(II) complexes that display intramolecular electron transfer from manganese(II) to photooxidized ruthenium(III). The electron-transfer rate constant (k(ET)) values span a large range, 1 x 10(5)-2 x 10(7) s(-1), and we have investigated different factors that are responsible for the variation. The reorganization energies determined experimentally (lambda = 1.5-2.0 eV) are larger than expected for solvent reorganization in complexes of similar size in polar solvents (typically lambda approximately 1.0 eV). This result indicates that the inner reorganization energy is relatively large and, consequently, that at moderate driving force values manganese complexes are not fast donors. Both the type of manganese ligand and the link between the two metals are shown to be of great importance to the electron-transfer rate. In contrast, we show that the quenching of the excited state of the ruthenium(II) moiety by manganese(II) in this series of complexes mainly depends on the distance between the metals. However, by synthetically modifying the sensitizer so that the lowest metal-to-ligand charge transfer state was localized on the nonbridging ruthenium(II) ligands, we could reduce the quenching rate constant in one complex by a factor of 700 without changing the bridging ligand. Still, the manganese(II)-ruthenium(III) electron-transfer rate constant was not reduced. Consequently, the modification resulted in a complex with very favorable properties.
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Affiliation(s)
- Malin L A Abrahamsson
- Department of Physical Chemistry, Uppsala University, Box 532, S-751 21 Uppsala, Sweden
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Hammarström L, Sun L, Akermark B, Styring S. A biomimetic approach to artificial photosynthesis: Ru(II)-polypyridine photo-sensitisers linked to tyrosine and manganese electron donors. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2001; 57:2145-2160. [PMID: 11603836 DOI: 10.1016/s1386-1425(01)00491-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The paper describes recent advances towards the construction of functional mimics of the oxygen evolving complex in photosystem II (PSII) that are coupled to photoinduced charge separation. Some key principles of PSII and artificial systems for light-induced charge accumulation are discussed. Systems are described where biomimetic electron donors--manganese complexes and tyrosine--have been linked to a Ru(II)-polypyridine photosensitiser. Oxidation of the donors by intramolecular electron transfer from the photo-oxidised Ru(III) complex has been studied using optical flash photolysis and EPR experiments. A step-wise electron transfer Mn(III,III)-->tyrosine Ru(III) has been demonstrated, in analogy to the reaction on the donor side of PSII. Electron transfer from the tyrosine to Ru(III) was coupled to tyrosine deprotonation. This resulted in a large reorganisation energy and thus a slow reaction rate, unless the tyrosine was hydrogen bonded or already deprotonated. A comparison with analogous reactions in PSII is made. Finally, light-induced oxidation of a manganese dimer linked to a Ru(II)-photosensitiser has been observed. Preliminary results suggest the possibility of photo-oxidising manganese dimers in several steps, which is an important advancement towards water oxidation.
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Affiliation(s)
- L Hammarström
- Department of Physical Chemistry, Uppsala University, Sweden.
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Kilså K, Kajanus J, Larsson S, Macpherson AN, Mårtensson J, Albinsson B. Enhanced intersystem crossing in donor/acceptor systems based on zinc/iron or free-base/iron porphyrins. Chemistry 2001; 7:2122-33. [PMID: 11411985 DOI: 10.1002/1521-3765(20010518)7:10<2122::aid-chem2122>3.0.co;2-n] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The deactivation pathways of the singlet excited state of a series of zinc or free-base donor porphyrins covalently linked by a bridge to a paramagnetic iron(III) chloride porphyrin acceptor have been studied. These donor-bridge-acceptor systems all share a similar geometry (25 A donor-acceptor center-to-center distance), but the bridges vary in electronic structure. In previously reported investigations of zinc/iron porphyrin systems, the fluorescence quenching of the donor has predominantly been assigned to electron transfer. However, for the porphyrin systems studied in this paper, we show that the dominant deactivation channels are enhanced intersystem crossing and singlet energy transfer. In both series, the intersystem crossing rate (S1-->T1) of the donor moiety is almost doubled in the presence of a paramagnetic high-spin metal-porphyrin acceptor. The significant spectral overlap of the donor fluorescence and acceptor absorption in both series allows for efficient singlet energy transfer (Forster mechanism). Furthermore, the bridging chromophores mediate energy transfer and the enhancement is inversely dependent upon the energy gap between the donor and bridge excited states. Although Marcus theory predicts thermodynamically favorable electron transfer to occur in the systems investigated, the quenching rate constants were found to be independent of solvent polarity, and no charge-separated state could be detected, indicating very small electronic coupling for electron transfer.
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Affiliation(s)
- K Kilså
- Department of Physical Chemistry, Chalmers University of Technology, Göteborg, Sweden
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Berg K, Tran A, Raymond M, Abrahamsson M, Wolny J, Redon S, Andersson M, Sun L, Styring S, Hammarström L, Toftlund H, Åkermark B. Covalently Linked Ruthenium(II)−Manganese(II) Complexes: Distance Dependence of Quenching and Electron Transfer. Eur J Inorg Chem 2001. [DOI: 10.1002/1099-0682(200104)2001:4<1019::aid-ejic1019>3.0.co;2-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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