1
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Witas K, Nair SS, Maisuradze T, Zedler L, Schmidt H, Garcia-Porta P, Rein ASJ, Bolter T, Rau S, Kupfer S, Dietzek-Ivanšić B, Sorsche DU. Beyond the First Coordination Sphere─Manipulating the Excited-State Landscape in Iron(II) Chromophores with Protons. J Am Chem Soc 2024; 146:19710-19719. [PMID: 38990184 PMCID: PMC11273614 DOI: 10.1021/jacs.4c00552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 06/14/2024] [Accepted: 06/17/2024] [Indexed: 07/12/2024]
Abstract
Molecular transition metal chromophores play a central role in light harvesting and energy conversion. Recently, earth-abundant transition-metal-based chromophores have begun to challenge the dominance of platinum group metal complexes in this area. However, the development of new chromophores with optimized photophysical properties is still limited by a lack of synthetic methods, especially with respect to heteroleptic complexes with functional ligands. Here, we demonstrate a facile and efficient method for the combination of strong-field carbenes with the functional 2,2'-bibenzimidazole ligand in a heteroleptic iron(II) chromophore complex. Our approach yields two isomers that differ predominantly in their excited-state lifetimes based on the symmetry of the ligand field. Deprotonation of both isomers leads to a significant red-shift of the metal-to-ligand charge transfer (MLCT) absorption and a shortening of excited-state lifetimes. Femtosecond transient absorption spectroscopy in combination with quantum chemical simulations and resonance Raman spectroscopy reveals the complex relationship between protonation and photophysical properties. Protonation is found to tip the balance between MLCT and metal-centered (MC) excited states in favor of the former. This study showcases the first example of fine-tuning of the excited-state landscape in an iron(II) chromophore through second-sphere manipulations and provides a new perspective to the challenge of excited-state optimizations in 3d transition metal chromophores.
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Affiliation(s)
- Kamil Witas
- Institute
for Inorganic Chemistry 1, Ulm University
(UUlm), Albert-Einstein-Allee 11, Ulm 89081, Germany
| | - Shruthi Santhosh Nair
- Research
Department Functional Interfaces, Leibniz
Institute of Photonic Technology (Leibniz-IPHT), Albert-Einstein-Straße 9, Jena 07745, Germany
- Institute
for Physical Chemistry, Friedrich-Schiller-Universität
Jena (FSU Jena), Lessingstraße 4, Jena 07743, Germany
| | - Tamar Maisuradze
- Institute
for Physical Chemistry, Friedrich-Schiller-Universität
Jena (FSU Jena), Lessingstraße 4, Jena 07743, Germany
| | - Linda Zedler
- Research
Department Functional Interfaces, Leibniz
Institute of Photonic Technology (Leibniz-IPHT), Albert-Einstein-Straße 9, Jena 07745, Germany
- Institute
for Physical Chemistry, Friedrich-Schiller-Universität
Jena (FSU Jena), Lessingstraße 4, Jena 07743, Germany
| | - Heiner Schmidt
- Research
Department Functional Interfaces, Leibniz
Institute of Photonic Technology (Leibniz-IPHT), Albert-Einstein-Straße 9, Jena 07745, Germany
- Institute
for Physical Chemistry, Friedrich-Schiller-Universität
Jena (FSU Jena), Lessingstraße 4, Jena 07743, Germany
| | - Pablo Garcia-Porta
- Institute
for Inorganic Chemistry 1, Ulm University
(UUlm), Albert-Einstein-Allee 11, Ulm 89081, Germany
| | | | - Tim Bolter
- Institute
for Inorganic Chemistry 1, Ulm University
(UUlm), Albert-Einstein-Allee 11, Ulm 89081, Germany
| | - Sven Rau
- Institute
for Inorganic Chemistry 1, Ulm University
(UUlm), Albert-Einstein-Allee 11, Ulm 89081, Germany
| | - Stephan Kupfer
- Institute
for Physical Chemistry, Friedrich-Schiller-Universität
Jena (FSU Jena), Lessingstraße 4, Jena 07743, Germany
| | - Benjamin Dietzek-Ivanšić
- Research
Department Functional Interfaces, Leibniz
Institute of Photonic Technology (Leibniz-IPHT), Albert-Einstein-Straße 9, Jena 07745, Germany
- Institute
for Physical Chemistry, Friedrich-Schiller-Universität
Jena (FSU Jena), Lessingstraße 4, Jena 07743, Germany
| | - Dieter U. Sorsche
- Institute
for Inorganic Chemistry 1, Ulm University
(UUlm), Albert-Einstein-Allee 11, Ulm 89081, Germany
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2
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Wellauer J, Ziereisen F, Sinha N, Prescimone A, Velić A, Meyer F, Wenger OS. Iron(III) Carbene Complexes with Tunable Excited State Energies for Photoredox and Upconversion. J Am Chem Soc 2024; 146. [PMID: 38598280 PMCID: PMC11046485 DOI: 10.1021/jacs.4c00605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 03/13/2024] [Accepted: 03/19/2024] [Indexed: 04/11/2024]
Abstract
Substituting precious elements in luminophores and photocatalysts by abundant first-row transition metals remains a significant challenge, and iron continues to be particularly attractive owing to its high natural abundance and low cost. Most iron complexes known to date face severe limitations due to undesirably efficient deactivation of luminescent and photoredox-active excited states. Two new iron(III) complexes with structurally simple chelate ligands enable straightforward tuning of ground and excited state properties, contrasting recent examples, in which chemical modification had a minor impact. Crude samples feature two luminescence bands strongly reminiscent of a recent iron(III) complex, in which this observation was attributed to dual luminescence, but in our case, there is clear-cut evidence that the higher-energy luminescence stems from an impurity and only the red photoluminescence from a doublet ligand-to-metal charge transfer (2LMCT) excited state is genuine. Photoinduced oxidative and reductive electron transfer reactions with methyl viologen and 10-methylphenothiazine occur with nearly diffusion-limited kinetics. Photocatalytic reactions not previously reported for this compound class, in particular the C-H arylation of diazonium salts and the aerobic hydroxylation of boronic acids, were achieved with low-energy red light excitation. Doublet-triplet energy transfer (DTET) from the luminescent 2LMCT state to an anthracene annihilator permits the proof of principle for triplet-triplet annihilation upconversion based on a molecular iron photosensitizer. These findings are relevant for the development of iron complexes featuring photophysical and photochemical properties competitive with noble-metal-based compounds.
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Affiliation(s)
- Joël Wellauer
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Fabienne Ziereisen
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Narayan Sinha
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Alessandro Prescimone
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Ajdin Velić
- University
of Göttingen, Institute of Inorganic Chemistry, Tammannstraße 4, D-37077 Göttingen, Germany
| | - Franc Meyer
- University
of Göttingen, Institute of Inorganic Chemistry, Tammannstraße 4, D-37077 Göttingen, Germany
| | - Oliver S. Wenger
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
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3
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Losada IB, Persson P. Photoredox matching of earth-abundant photosensitizers with hydrogen evolving catalysts by first-principles predictions. J Chem Phys 2024; 160:074302. [PMID: 38375904 DOI: 10.1063/5.0174837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 01/09/2024] [Indexed: 02/21/2024] Open
Abstract
Photoredox properties of several earth-abundant light-harvesting transition metal complexes in combination with cobalt-based proton reduction catalysts have been investigated computationally to assess the fundamental viability of different photocatalytic systems of current experimental interest. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations using several GGA (BP86, BLYP), hybrid-GGA (B3LYP, B3LYP*), hybrid meta-GGA (M06, TPSSh), and range-separated hybrid (ωB97X, CAM-B3LYP) functionals were used to calculate relevant ground and excited state reduction potentials for photosensitizers, catalysts, and sacrificial electron donors. Linear energy correction factors for the DFT/TD-DFT results that provide the best agreement with available experimental reference results were determined in order to provide more accurate predictions. Among the selection of functionals, the B3LYP* and TPSSh sets of correction parameters were determined to give the best redox potentials and excited states energies, ΔEexc, with errors of ∼0.2 eV. Linear corrections for both reduction and oxidation processes significantly improve the predictions for all the redox pairs. In particular, for TPSSh and B3LYP*, the calculated errors decrease by more than 0.5 V against experimental values for catalyst reduction potentials, photosensitizer oxidation potentials, and electron donor oxidation potentials. Energy-corrected TPSSh results were finally used to predict the energetics of complete photocatalytic cycles for the light-driven activation of selected proton reduction cobalt catalysts. These predictions demonstrate the broader usefulness of the adopted approach to systematically predict full photocycle behavior for first-row transition metal photosensitizer-catalyst combinations more broadly.
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Affiliation(s)
- Iria Bolaño Losada
- Division of Computational Chemistry, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
| | - Petter Persson
- Division of Computational Chemistry, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
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4
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Prakash O, Lindh L, Gupta AK, Hoang Hai YT, Kaul N, Chábera P, Lindgren F, Ericsson T, Häggström L, Strand D, Yartsev A, Lomoth R, Persson P, Wärnmark K. Tailoring the Photophysical Properties of a Homoleptic Iron(II) Tetra N-Heterocyclic Carbene Complex by Attaching an Imidazolium Group to the (C ∧N ∧C) Pincer Ligand─A Comparative Study. Inorg Chem 2024; 63:2909-2918. [PMID: 38301278 PMCID: PMC10865346 DOI: 10.1021/acs.inorgchem.3c02890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 01/09/2024] [Accepted: 01/11/2024] [Indexed: 02/03/2024]
Abstract
We here report the synthesis of the homoleptic iron(II) N-heterocyclic carbene (NHC) complex [Fe(miHpbmi)2](PF6)4 (miHpbmi = 4-((3-methyl-1H-imidazolium-1-yl)pyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)) and its electrochemical and photophysical properties. The introduction of the π-electron-withdrawing 3-methyl-1H-imidazol-3-ium-1-yl group into the NHC ligand framework resulted in stabilization of the metal-to-ligand charge transfer (MLCT) state and destabilization of the metal-centered (MC) states. This resulted in an improved excited-state lifetime of 16 ps compared to the 9 ps for the unsubstituted parent compound [Fe(pbmi)2](PF6)2 (pbmi = (pyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)) as well as a stronger MLCT absorption band extending more toward the red spectral region. However, compared to the carboxylic acid derivative [Fe(cpbmi)2](PF6)2 (cpbmi = 1,1'-(4-carboxypyridine-2,6-diyl)bis(3-methylimidazol-2-ylidene)), the excited-state lifetime of [Fe(miHpbmi)2](PF6)4 is the same, but both the extinction and the red shift are more pronounced for the former. Hence, this makes [Fe(miHpbmi)2](PF6)4 a promising pH-insensitive analogue of [Fe(cpbmi)2](PF6)2. Finally, the excited-state dynamics of the title compound [Fe(miHpbmi)2](PF6)4 was investigated in solvents with different viscosities, however, showing very little dependency of the depopulation of the excited states on the properties of the solvent used.
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Affiliation(s)
- Om Prakash
- Centre
for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, Lund SE-22100, Sweden
| | - Linnea Lindh
- Chemical
Physics Division, Department of Chemistry, Lund University, Box 124, Lund SE-22100, Sweden
- Theoretical
Chemistry Division, Department of Chemistry, Lund University, Box 124, Lund SE-22100, Sweden
| | - Arvind Kumar Gupta
- Centre
for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, Lund SE-22100, Sweden
| | - Yen Tran Hoang Hai
- Theoretical
Chemistry Division, Department of Chemistry, Lund University, Box 124, Lund SE-22100, Sweden
| | - Nidhi Kaul
- Department
of Chemistry—Ångström Laboratory, Uppsala University, Box 523, Uppsala SE-751 20, Sweden
| | - Pavel Chábera
- Chemical
Physics Division, Department of Chemistry, Lund University, Box 124, Lund SE-22100, Sweden
| | - Fredrik Lindgren
- Department
of Chemistry—Ångström Laboratory, Uppsala University, Box 523, Uppsala SE-751 20, Sweden
| | - Tore Ericsson
- Department of Physics—Ångström
Laboratory, Uppsala University, Box 523, Uppsala SE-751
20, Sweden
| | - Lennart Häggström
- Department of Physics—Ångström
Laboratory, Uppsala University, Box 523, Uppsala SE-751
20, Sweden
| | - Daniel Strand
- Centre
for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, Lund SE-22100, Sweden
| | - Arkady Yartsev
- Chemical
Physics Division, Department of Chemistry, Lund University, Box 124, Lund SE-22100, Sweden
| | - Reiner Lomoth
- Department
of Chemistry—Ångström Laboratory, Uppsala University, Box 523, Uppsala SE-751 20, Sweden
| | - Petter Persson
- Theoretical
Chemistry Division, Department of Chemistry, Lund University, Box 124, Lund SE-22100, Sweden
| | - Kenneth Wärnmark
- Centre
for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, Lund SE-22100, Sweden
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5
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Johnson CE, Schwarz J, Deegbey M, Prakash O, Sharma K, Huang P, Ericsson T, Häggström L, Bendix J, Gupta AK, Jakubikova E, Wärnmark K, Lomoth R. Ferrous and ferric complexes with cyclometalating N-heterocyclic carbene ligands: a case of dual emission revisited. Chem Sci 2023; 14:10129-10139. [PMID: 37772113 PMCID: PMC10530338 DOI: 10.1039/d3sc02806b] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 08/27/2023] [Indexed: 09/30/2023] Open
Abstract
Iron N-heterocyclic carbene (FeNHC) complexes with long-lived charge transfer states are emerging as a promising class of photoactive materials. We have synthesized [FeII(ImP)2] (ImP = bis(2,6-bis(3-methylimidazol-2-ylidene-1-yl)phenylene)) that combines carbene ligands with cyclometalation for additionally improved ligand field strength. The 9 ps lifetime of its 3MLCT (metal-to-ligand charge transfer) state however reveals no benefit from cyclometalation compared to Fe(ii) complexes with NHC/pyridine or pure NHC ligand sets. In acetonitrile solution, the Fe(ii) complex forms a photoproduct that features emission characteristics (450 nm, 5.1 ns) that were previously attributed to a higher (2MLCT) state of its Fe(iii) analogue [FeIII(ImP)2]+, which led to a claim of dual (MLCT and LMCT) emission. Revisiting the photophysics of [FeIII(ImP)2]+, we confirmed however that higher (2MLCT) states of [FeIII(ImP)2]+ are short-lived (<10 ps) and therefore, in contrast to the previous interpretation, cannot give rise to emission on the nanosecond timescale. Accordingly, pristine [FeIII(ImP)2]+ prepared by us only shows red emission from its lower 2LMCT state (740 nm, 240 ps). The long-lived, higher energy emission previously reported for [FeIII(ImP)2]+ is instead attributed to an impurity, most probably a photoproduct of the Fe(ii) precursor. The previously reported emission quenching on the nanosecond time scale hence does not support any excited state reactivity of [FeIII(ImP)2]+ itself.
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Affiliation(s)
- Catherine Ellen Johnson
- Department of Chemistry -Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Jesper Schwarz
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University Box 124 SE-22100 Lund Sweden
| | - Mawuli Deegbey
- Department of Chemistry, North Carolina State University Raleigh North Carolina 27695 USA
| | - Om Prakash
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University Box 124 SE-22100 Lund Sweden
| | - Kumkum Sharma
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University Box 124 SE-22100 Lund Sweden
| | - Ping Huang
- Department of Chemistry -Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Tore Ericsson
- Department of Physics - Ångström Laboratory, Uppsala University Box 523 SE-751 20 Uppsala Sweden
| | - Lennart Häggström
- Department of Physics - Ångström Laboratory, Uppsala University Box 523 SE-751 20 Uppsala Sweden
| | - Jesper Bendix
- Department of Chemistry, University of Copenhagen Universitetsparken 5 DK-2100 Copenhagen Denmark
| | - Arvind Kumar Gupta
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University Box 124 SE-22100 Lund Sweden
| | - Elena Jakubikova
- Department of Chemistry, North Carolina State University Raleigh North Carolina 27695 USA
| | - Kenneth Wärnmark
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University Box 124 SE-22100 Lund Sweden
| | - Reiner Lomoth
- Department of Chemistry -Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
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6
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Prakash O, Lindh L, Kaul N, Rosemann NW, Losada IB, Johnson C, Chábera P, Ilic A, Schwarz J, Gupta AK, Uhlig J, Ericsson T, Häggström L, Huang P, Bendix J, Strand D, Yartsev A, Lomoth R, Persson P, Wärnmark K. Photophysical Integrity of the Iron(III) Scorpionate Framework in Iron(III)–NHC Complexes with Long-Lived 2LMCT Excited States. Inorg Chem 2022; 61:17515-17526. [DOI: 10.1021/acs.inorgchem.2c02410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Om Prakash
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-22100Lund, Sweden
| | - Linnea Lindh
- Chemical Physics Division, Department of Chemistry, Lund University, Box 124, SE-22100Lund, Sweden
- Theoretical Chemistry Division, Department of Chemistry, Lund University, Box 124, SE-22100Lund, Sweden
| | - Nidhi Kaul
- Department of Chemistry − Ångström Laboratory, Uppsala University, Box 523, SE-75120Uppsala, Sweden
| | - Nils W. Rosemann
- Chemical Physics Division, Department of Chemistry, Lund University, Box 124, SE-22100Lund, Sweden
| | - Iria Bolaño Losada
- Theoretical Chemistry Division, Department of Chemistry, Lund University, Box 124, SE-22100Lund, Sweden
| | - Catherine Johnson
- Department of Chemistry − Ångström Laboratory, Uppsala University, Box 523, SE-75120Uppsala, Sweden
| | - Pavel Chábera
- Chemical Physics Division, Department of Chemistry, Lund University, Box 124, SE-22100Lund, Sweden
| | - Aleksandra Ilic
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-22100Lund, Sweden
| | - Jesper Schwarz
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-22100Lund, Sweden
| | - Arvind Kumar Gupta
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-22100Lund, Sweden
| | - Jens Uhlig
- Chemical Physics Division, Department of Chemistry, Lund University, Box 124, SE-22100Lund, Sweden
| | - Tore Ericsson
- Department of Physics − Ångström Laboratory, Uppsala University, Box 523, SE-75120Uppsala, Sweden
| | - Lennart Häggström
- Department of Physics − Ångström Laboratory, Uppsala University, Box 523, SE-75120Uppsala, Sweden
| | - Ping Huang
- Department of Chemistry − Ångström Laboratory, Uppsala University, Box 523, SE-75120Uppsala, Sweden
| | - Jesper Bendix
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100Copenhagen, Denmark
| | - Daniel Strand
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-22100Lund, Sweden
| | - Arkady Yartsev
- Chemical Physics Division, Department of Chemistry, Lund University, Box 124, SE-22100Lund, Sweden
| | - Reiner Lomoth
- Department of Chemistry − Ångström Laboratory, Uppsala University, Box 523, SE-75120Uppsala, Sweden
| | - Petter Persson
- Theoretical Chemistry Division, Department of Chemistry, Lund University, Box 124, SE-22100Lund, Sweden
| | - Kenneth Wärnmark
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-22100Lund, Sweden
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7
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Recent Advances in Metal-Based Molecular Photosensitizers for Artificial Photosynthesis. Catalysts 2022. [DOI: 10.3390/catal12080919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Artificial photosynthesis (AP) has been extensively applied in energy conversion and environment pollutants treatment. Considering the urgent demand for clean energy for human society, many researchers have endeavored to develop materials for AP. Among the materials for AP, photosensitizers play a critical role in light absorption and charge separation. Due to the fact of their excellent tunability and performance, metal-based complexes stand out from many photocatalysis photosensitizers. In this review, the evaluation parameters for photosensitizers are first summarized and then the recent developments in molecular photosensitizers based on transition metal complexes are presented. The photosensitizers in this review are divided into two categories: noble-metal-based and noble-metal-free complexes. The subcategories for each type of photosensitizer in this review are organized by element, focusing first on ruthenium, iridium, and rhenium and then on manganese, iron, and copper. Various examples of recently developed photosensitizers are also presented.
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8
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Schwarz J, Ilic A, Johnson C, Lomoth R, Wärnmark K. High turnover photocatalytic hydrogen formation with an Fe(III) N-heterocyclic carbene photosensitiser. Chem Commun (Camb) 2022; 58:5351-5354. [PMID: 35373799 DOI: 10.1039/d2cc01016j] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein we report the first high turnover photocatalytic hydrogen formation reaction based on an earth-abundant FeIII-NHC photosensitiser. The reaction occurs via reductive quenching of the 2LMCT excited state that can be directly excited with green light and employs either Pt-colloids or [Co(dmgH)2pyCl] as proton reduction catalysts and [HNEt3][BF4] and triethanolamine/triethylamine as proton and electron donors. The outstanding photostability of the FeIII-NHC complex enables turnover numbers >1000 without degradation.
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Affiliation(s)
- Jesper Schwarz
- Centre for Analysis and Synthesis (CAS), Department of Chemistry, Lund University, SE-22100 Lund, Sweden.
| | - Aleksandra Ilic
- Centre for Analysis and Synthesis (CAS), Department of Chemistry, Lund University, SE-22100 Lund, Sweden.
| | - Catherine Johnson
- Department of Chemistry-Ångström Laboratory, Uppsala University, SE-75120 Uppsala, Sweden.
| | - Reiner Lomoth
- Department of Chemistry-Ångström Laboratory, Uppsala University, SE-75120 Uppsala, Sweden.
| | - Kenneth Wärnmark
- Centre for Analysis and Synthesis (CAS), Department of Chemistry, Lund University, SE-22100 Lund, Sweden.
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9
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Moll J, Förster C, König A, Carrella LM, Wagner M, Panthöfer M, Möller A, Rentschler E, Heinze K. Panchromatic Absorption and Oxidation of an Iron(II) Spin Crossover Complex. Inorg Chem 2022; 61:1659-1671. [PMID: 35020386 DOI: 10.1021/acs.inorgchem.1c03511] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In order to expand and exploit the useful properties of d6-iron(II) and d5-iron(III) complexes in potential magnetic, photophysical, or magnetooptical applications, crucial ligand-controlled parameters are the ligand field strength in a given coordination mode and the availability of suitable metal and ligand frontier orbitals for charge-transfer processes. The push-pull ligand 2,6-diguanidylpyridine (dgpy) features low-energy π* orbitals at the pyridine site and strongly electron-donating guanidinyl donors combined with the ability to form six-membered chelate rings for optimal metal-ligand orbital overlap. The electronic ground states of the pseudo-octahedral d6- and d5-complexes mer-[Fe(dgpy)2]2+, cis-fac-[Fe(dgpy)2]2+, and mer-[Fe(dgpy)2]3+ as well as their charge-transfer (CT) and metal-centered (MC) excited states are probed by variable temperature UV/vis absorption, NMR, EPR, and Mössbauer spectroscopy, magnetic susceptibility measurements at variable temperature as well as quantum chemical calculations.
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Affiliation(s)
- Johannes Moll
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Christoph Förster
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Alexandra König
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Luca M Carrella
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Manfred Wagner
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Martin Panthöfer
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Angela Möller
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Eva Rentschler
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Katja Heinze
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
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10
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Dierks P, Vukadinovic Y, Bauer M. Photoactive iron complexes: more sustainable, but still a challenge. Inorg Chem Front 2022. [DOI: 10.1039/d1qi01112j] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
With the “Criticality Score” used as a benchmark for sustainability – potentials, strategies and challenges are discussed to replace noble metal compounds in photosensitizers by the sustainable alternative iron.
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Affiliation(s)
- Philipp Dierks
- Faculty of Science, Chemistry Department and Center for Sustainable Systems Design, Paderborn University, 33098 Paderborn, Germany
| | - Yannik Vukadinovic
- Faculty of Science, Chemistry Department and Center for Sustainable Systems Design, Paderborn University, 33098 Paderborn, Germany
| | - Matthias Bauer
- Faculty of Science, Chemistry Department and Center for Sustainable Systems Design, Paderborn University, 33098 Paderborn, Germany
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11
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Hainer F, Alagna N, Reddy Marri A, Penfold TJ, Gros PC, Haacke S, Buckup T. Vibrational Coherence Spectroscopy Identifies Ultrafast Branching in an Iron(II) Sensitizer. J Phys Chem Lett 2021; 12:8560-8565. [PMID: 34468159 DOI: 10.1021/acs.jpclett.1c01580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The introduction of N-heterocyclic carbene ligands has greatly increased the lifetimes of metal-to-ligand charge transfer states (MLCT) in iron(II) complexes, making them promising candidates for photocatalytic applications. However, the spectrally elusive triplet metal-centered state (3MC) has been suggested to play a decisive role in the relaxation of the MLCT manifold to the ground state, shortening their lifetimes and consequently limiting the application potential. In this work, time-resolved vibrational spectroscopy and quantum chemical calculations are applied to shed light on the 3MCs' involvement in the deactivation of the MLCT manifold of an iron(II) sensitizer. Two distinct symmetric Fe-L breathing vibrations at frequencies below 150 cm-1 are assigned to the 3MC and 3MLCT states by quantum chemical calculations. On the basis of this assignment, an ultrafast branching directly after excitation forms not only the long-lived 3MLCT but also the 3MC as an additional loss channel.
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Affiliation(s)
- F Hainer
- Physikalisch Chemisches Institut, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany
- Centre for Advanced Materials, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany
| | - N Alagna
- Physikalisch Chemisches Institut, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany
- Centre for Advanced Materials, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany
| | - A Reddy Marri
- Université de Lorraine, CNRS, L2CM, F-54000 Nancy, France
| | - T J Penfold
- Chemistry, School of Natural and Environmental Sciences, Newcastle University, NE1 7RU Newcastle Upon Tyne, United Kingdom
| | - P C Gros
- Université de Lorraine, CNRS, L2CM, F-54000 Nancy, France
| | - S Haacke
- University of Strasbourg, CNRS, IPCMS, 67034 Strasbourg, France
| | - T Buckup
- Physikalisch Chemisches Institut, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany
- Centre for Advanced Materials, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany
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12
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Huber‐Gedert M, Nowakowski M, Kertmen A, Burkhardt L, Lindner N, Schoch R, Herbst‐Irmer R, Neuba A, Schmitz L, Choi T, Kubicki J, Gawelda W, Bauer M. Fundamental Characterization, Photophysics and Photocatalysis of a Base Metal Iron(II)-Cobalt(III) Dyad. Chemistry 2021; 27:9905-9918. [PMID: 33884671 PMCID: PMC8362051 DOI: 10.1002/chem.202100766] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Indexed: 12/13/2022]
Abstract
A new base metal iron-cobalt dyad has been obtained by connection between a heteroleptic tetra-NHC iron(II) photosensitizer combining a 2,6-bis[3-(2,6-diisopropylphenyl)imidazol-2-ylidene]pyridine with 2,6-bis(3-methyl-imidazol-2-ylidene)-4,4'-bipyridine ligand, and a cobaloxime catalyst. This novel iron(II)-cobalt(III) assembly has been extensively characterized by ground- and excited-state methods like X-ray crystallography, X-ray absorption spectroscopy, (spectro-)electrochemistry, and steady-state and time-resolved optical absorption spectroscopy, with a particular focus on the stability of the molecular assembly in solution and determination of the excited-state landscape. NMR and UV/Vis spectroscopy reveal dissociation of the dyad in acetonitrile at concentrations below 1 mM and high photostability. Transient absorption spectroscopy after excitation into the metal-to-ligand charge transfer absorption band suggests a relaxation cascade originating from hot singlet and triplet MLCT states, leading to the population of the 3 MLCT state that exhibits the longest lifetime. Finally, decay into the ground state involves a 3 MC state. Attachment of cobaloxime to the iron photosensitizer increases the 3 MLCT lifetime at the iron centre. Together with the directing effect of the linker, this potentially makes the dyad more active in photocatalytic proton reduction experiments than the analogous two-component system, consisting of the iron photosensitizer and Co(dmgH)2 (py)Cl. This work thus sheds new light on the functionality of base metal dyads, which are important for more efficient and sustainable future proton reduction systems.
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Affiliation(s)
- Marina Huber‐Gedert
- Department ChemieUniversität PaderbornWarburger Straße 10033098PaderbornGermany
| | - Michał Nowakowski
- Department ChemieUniversität PaderbornWarburger Straße 10033098PaderbornGermany
| | - Ahmet Kertmen
- Faculty of PhysicsAdam Mickiewicz University Poznańul. Uniwersytetu Poznańskiego 2Poznań61-614Poland
| | - Lukas Burkhardt
- Department ChemieUniversität PaderbornWarburger Straße 10033098PaderbornGermany
| | - Natalia Lindner
- Faculty of PhysicsAdam Mickiewicz University Poznańul. Uniwersytetu Poznańskiego 2Poznań61-614Poland
| | - Roland Schoch
- Department ChemieUniversität PaderbornWarburger Straße 10033098PaderbornGermany
| | - Regine Herbst‐Irmer
- Institut für Anorganische ChemieUniversität GöttingenTammannstraße 437077GöttingenGermany
| | - Adam Neuba
- Department ChemieUniversität PaderbornWarburger Straße 10033098PaderbornGermany
| | - Lennart Schmitz
- Department ChemieUniversität PaderbornWarburger Straße 10033098PaderbornGermany
| | | | - Jacek Kubicki
- Faculty of PhysicsAdam Mickiewicz University Poznańul. Uniwersytetu Poznańskiego 2Poznań61-614Poland
| | - Wojciech Gawelda
- Faculty of PhysicsAdam Mickiewicz University Poznańul. Uniwersytetu Poznańskiego 2Poznań61-614Poland
- Department of ChemistryUniversidad Autónoma de MadridCampus Universitario28049MadridSpain
- IMDEA-NanocienciaCalle Faraday 928049MadridSpain
| | - Matthias Bauer
- Department ChemieUniversität PaderbornWarburger Straße 10033098PaderbornGermany
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13
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Nair SS, Bysewski OA, Kupfer S, Wächtler M, Winter A, Schubert US, Dietzek B. Excitation Energy-Dependent Branching Dynamics Determines Photostability of Iron(II)-Mesoionic Carbene Complexes. Inorg Chem 2021; 60:9157-9173. [PMID: 34081456 DOI: 10.1021/acs.inorgchem.1c01166] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Photoactive metal complexes containing earth-abundant transition metals recently gained interest as photosensitizers in light-driven chemistry. In contrast to the traditionally employed ruthenium or iridium complexes, iron complexes developed to be promising candidates despite the fact that using iron complexes as photosensitizers poses an inherent challenge associated with the low-lying metal-centered states, which are responsible for ultrafast deactivation of the charge-transfer states. Nonetheless, recent developments of strongly σ-donating carbene ligands yielded highly promising systems, in which destabilized metal-centered states resulted in prolonged lifetimes of charge-transfer excited states. In this context, we introduce a series of novel homoleptic Fe-triazolylidene mesoionic carbene complexes. The excited-state properties of the complexes were investigated by time-resolved femtosecond transient absorption spectroscopy and quantum chemical calculations. Pump wavelength-dependent transient absorption reveals the presence of distinct excited-state relaxation pathways. We relate the excitation-wavelength-dependent branching of the excited-state dynamics into various reaction channels to solvent-dependent photodissociation following the population of dissociative metal centered states upon excitation at 400 nm.
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Affiliation(s)
- Shruthi S Nair
- Department Functional Interfaces, Leibniz Institute of Photonic Technology (Leibniz-IPHT), Albert-Einstein-Strasse 9, 07745 Jena, Germany.,Institute of Physical Chemistry, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Oliver A Bysewski
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich-Schiller University Jena, Humboldtstrasse 10, 07743 Jena, Germany.,Center for Energy and Environmental Chemistry Jena (CEEC-Jena), Friedrich-Schiller University Jena, Philosophenweg, 07743 Jena, Germany
| | - Stephan Kupfer
- Institute of Physical Chemistry, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Maria Wächtler
- Department Functional Interfaces, Leibniz Institute of Photonic Technology (Leibniz-IPHT), Albert-Einstein-Strasse 9, 07745 Jena, Germany.,Institute of Physical Chemistry, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany.,Abbe Center of Photonics, Friedrich Schiller University Jena, Philosophenweg, 07745 Jena, Germany
| | - Andreas Winter
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich-Schiller University Jena, Humboldtstrasse 10, 07743 Jena, Germany.,Center for Energy and Environmental Chemistry Jena (CEEC-Jena), Friedrich-Schiller University Jena, Philosophenweg, 07743 Jena, Germany
| | - Ulrich S Schubert
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich-Schiller University Jena, Humboldtstrasse 10, 07743 Jena, Germany.,Center for Energy and Environmental Chemistry Jena (CEEC-Jena), Friedrich-Schiller University Jena, Philosophenweg, 07743 Jena, Germany
| | - Benjamin Dietzek
- Department Functional Interfaces, Leibniz Institute of Photonic Technology (Leibniz-IPHT), Albert-Einstein-Strasse 9, 07745 Jena, Germany.,Institute of Physical Chemistry, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
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14
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Doettinger F, Yang Y, Schmid MA, Frey W, Karnahl M, Tschierlei S. Cross-Coupled Phenyl- and Alkynyl-Based Phenanthrolines and Their Effect on the Photophysical and Electrochemical Properties of Heteroleptic Cu(I) Photosensitizers. Inorg Chem 2021; 60:5391-5401. [PMID: 33764043 DOI: 10.1021/acs.inorgchem.1c00416] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
With the aims of increasing the antenna system and improving the photophysical properties of Cu(I)-based photosensitizers, the backbone of 2,9-dimethyl-1,10-phenanthroline was selectively extended in the 5,6-position. Applying specifically tailored Suzuki-Miyaura and "chemistry-on-the-complex" Sonogashira cross-coupling reactions enabled the development of two sets of structurally related diimine ligands with a broad variety of different phenyl- and alkynyl-based substituents. The resulting 11 novel heteroleptic Cu(I) complexes, including five solid-state structures, were studied with respect to their structure-property relationships. Both sets of substituents are able to red-shift the absorption maxima and to increase the absorptivity. For the alkynyl-based complexes, this is accompanied by a significant anodic shift of the reduction potentials. The phenyl-based substituents strongly influence the emission wavelength and quantum yield of the resulting Cu(I) complexes and lead to an increase in the emission lifetime of up to 504 ns, which clearly indicates competition with the benchmark system [(xantphos)Cu(bathocuproine)]PF6.
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Affiliation(s)
- Florian Doettinger
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany.,Department of Energy Conversion, Institute of Physical and Theoretical Chemistry, Technische Universität Brauschweig, Gaußstraße 17, 38106 Braunschweig, Germany
| | - Yingya Yang
- Department of Energy Conversion, Institute of Physical and Theoretical Chemistry, Technische Universität Brauschweig, Gaußstraße 17, 38106 Braunschweig, Germany
| | - Marie-Ann Schmid
- Department of Energy Conversion, Institute of Physical and Theoretical Chemistry, Technische Universität Brauschweig, Gaußstraße 17, 38106 Braunschweig, Germany
| | - Wolfgang Frey
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Michael Karnahl
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Stefanie Tschierlei
- Department of Energy Conversion, Institute of Physical and Theoretical Chemistry, Technische Universität Brauschweig, Gaußstraße 17, 38106 Braunschweig, Germany
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15
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Chábera P, Lindh L, Rosemann NW, Prakash O, Uhlig J, Yartsev A, Wärnmark K, Sundström V, Persson P. Photofunctionality of iron(III) N-heterocyclic carbenes and related d transition metal complexes. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2020.213517] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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16
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Gonell S, Lloret-Fillol J, Miller AJM. An Iron Pyridyl-Carbene Electrocatalyst for Low Overpotential CO2 Reduction to CO. ACS Catal 2020. [DOI: 10.1021/acscatal.0c03798] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Sergio Gonell
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Avinguda Països Catalans, 16, 43007 Tarragona, Spain
| | - Julio Lloret-Fillol
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Avinguda Països Catalans, 16, 43007 Tarragona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluïs Companys, 23, 08010 Barcelona, Spain
| | - Alexander J. M. Miller
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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17
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Iron-Based Catalytically Active Complexes in Preparation of Functional Materials. Processes (Basel) 2020. [DOI: 10.3390/pr8121683] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Iron complexes are particularly interesting as catalyst systems over the other transition metals (including noble metals) due to iron’s high natural abundance and mediation in important biological processes, therefore making them non-toxic, cost-effective, and biocompatible. Both homogeneous and heterogeneous catalysis mediated by iron as a transition metal have found applications in many industries, including oxidation, C-C bond formation, hydrocarboxylation and dehydration, hydrogenation and reduction reactions of low molecular weight molecules. These processes provided substrates for industrial-scale use, e.g., switchable materials, sustainable and scalable energy storage technologies, drugs for the treatment of cancer, and high molecular weight polymer materials with a predetermined structure through controlled radical polymerization techniques. This review provides a detailed statement of the utilization of homogeneous and heterogeneous iron-based catalysts for the synthesis of both low and high molecular weight molecules with versatile use, focusing on receiving functional materials with high potential for industrial application.
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18
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Behm K, McIntosh RD. Application of Discrete First-Row Transition-Metal Complexes as Photosensitisers. Chempluschem 2020; 85:2611-2618. [PMID: 33263950 DOI: 10.1002/cplu.202000610] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 11/17/2020] [Indexed: 11/11/2022]
Abstract
This Minireview summarises and critically evaluates recent advances in the utilisation of discrete first-row transition-metal (TM) complexes as photosensitisers. Whilst many compounds absorb light, TM complexes are generally more desirable for photochemical applications, as they usually exhibit strong absorption of visible light, making them ideally suited to exploiting the sun as a freely available light source. Due to their outstanding activities, precious metals, such as iridium and ruthenium, are currently still at the forefront of photochemistry research. However, they also bear disadvantages with respect to abundance, cost and toxicity. Therefore, it is desirable to move to more abundant and less expensive systems that retain good photosensitising abilities. This Minireview will focus on first-row transition-metals, specifically titanium, copper, iron, and zinc, which have become the focus of increased attention over recent years as potential replacements for noble metals as photosensitisers. Their structure - activity relationships are explored and challenges in designing the ligands and complexes are discussed.
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Affiliation(s)
- Kira Behm
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom
| | - Ruaraidh D McIntosh
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom
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19
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Dierks P, Päpcke A, Bokareva OS, Altenburger B, Reuter T, Heinze K, Kühn O, Lochbrunner S, Bauer M. Ground- and Excited-State Properties of Iron(II) Complexes Linked to Organic Chromophores. Inorg Chem 2020; 59:14746-14761. [PMID: 32935979 DOI: 10.1021/acs.inorgchem.0c02039] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Two new bichromophoric complexes, [Fe(bim-ant)2]2+ and [Fe(bim-pyr)2]2+ ([H2-bim]2+ = 1,1'-(pyridine-2,6-diyl)bis(3-methyl-1H-imidazol-3-ium); ant = 9-anthracenyl; pyr = 1-pyrenyl), are investigated to explore the possibility of tuning the excited-state behavior in photoactive iron(II) complexes to design substitutes for noble-metal compounds. The ground-state properties of both complexes are characterized thoroughly by electrochemical methods and optical absorption spectroscopy, complemented by time-dependent density functional theory calculations. The excited states are investigated by static and time-resolved luminescence and femtosecond transient absorption spectroscopy. Both complexes exhibit room temperature luminescence, which originates from singlet states dominated by the chromophore (1Chrom). In the cationic pro-ligands and in the iron(II) complexes, the emission is shifted to red by up to 110 nm (5780 cm-1). This offers the possibility of tuning the organic chromophore emission by metal-ion coordination. The fluorescence lifetimes of the complexes are in the nanosecond range, while triplet metal-to-ligand charge-transfer (3MLCT) lifetimes are around 14 ps. An antenna effect as in ruthenium(II) polypyridine complexes connected to an organic chromophore is found in the form of an internal conversion within 3.4 ns from the 1Chrom to the 1MLCT states. Because no singlet oxygen forms from triplet oxygen in the presence of the iron(II) complexes and light, efficient intersystem crossing to the triplet state of the organic chromophore (3Chrom) is not promoted in the iron(II) complexes.
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Affiliation(s)
- Philipp Dierks
- Faculty of Science, Chemistry Department and Center for Sustainable Systems Design, Paderborn University, Warburger Strasse 100, 33098 Paderborn, Germany
| | - Ayla Päpcke
- Institute of Physics, University of Rostock, Albert-Einstein-Strasse 23-24, 18059 Rostock, Germany.,Department of Life, Light and Matter, University of Rostock, 18051 Rostock, Germany
| | - Olga S Bokareva
- Institute of Physics, University of Rostock, Albert-Einstein-Strasse 23-24, 18059 Rostock, Germany.,Department of Physical Chemistry, Kazan Federal University, Kremlevskaya Strasse 18, 420008, Kazan, Russia
| | - Björn Altenburger
- Institute of Physics, University of Rostock, Albert-Einstein-Strasse 23-24, 18059 Rostock, Germany.,Department of Physics, Chalmers University of Technology, Fysikgränd 3, SE-412 96 Göteborg, Sweden
| | - Thomas Reuter
- Department of Chemistry, Johannes Gutenberg University of Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Katja Heinze
- Department of Chemistry, Johannes Gutenberg University of Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Oliver Kühn
- Institute of Physics, University of Rostock, Albert-Einstein-Strasse 23-24, 18059 Rostock, Germany.,Department of Life, Light and Matter, University of Rostock, 18051 Rostock, Germany
| | - Stefan Lochbrunner
- Institute of Physics, University of Rostock, Albert-Einstein-Strasse 23-24, 18059 Rostock, Germany.,Department of Life, Light and Matter, University of Rostock, 18051 Rostock, Germany
| | - Matthias Bauer
- Faculty of Science, Chemistry Department and Center for Sustainable Systems Design, Paderborn University, Warburger Strasse 100, 33098 Paderborn, Germany
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20
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Zobel JP, Bokareva OS, Zimmer P, Wölper C, Bauer M, González L. Intersystem Crossing and Triplet Dynamics in an Iron(II) N-Heterocyclic Carbene Photosensitizer. Inorg Chem 2020; 59:14666-14678. [PMID: 32869981 PMCID: PMC7581298 DOI: 10.1021/acs.inorgchem.0c02147] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
![]()
The electronic excited
states of the iron(II) complex [FeII(tpy)(pyz-NHC)]2+ [tpy = 2,2′:6′,2″-terpyridine; pyz-NHC
= 1,1′-bis(2,6-diisopropylphenyl)pyrazinyldiimidazolium-2,2′-diylidene]
and their relaxation pathways have been theoretically investigated.
To this purpose, trajectory surface-hopping simulations within a linear
vibronic coupling model including a 244-dimensional potential energy
surface (PES) with 20 singlet and 20 triplet coupled states have been
used. The simulations show that, after excitation to the lowest-energy
absorption band of predominant metal-to-ligand charge-transfer character
involving the tpy ligand, almost 80% of the population undergoes intersystem
crossing to the triplet manifold in about 50 fs, while the remaining
20% decays through internal conversion to the electronic ground state
in about 300 fs. The population transferred to the triplet states
is found to deactivate into two different regions of the PESs, one
where the static dipole moment is small and shows increased metal-centered
character and another with a large static dipole moment, where the
electron density is transferred from the tpy to pyz-NHC ligand. Coherent
oscillations of 400 fs are observed between these two sets of triplet
populations, until the mixture equilibrates to a ratio of 60:40. Finally,
the importance of selecting suitable normal modes is highlighted—a
choice that can be far from straightforward in transition-metal complexes
with hundreds of degrees of freedom. Trajectory
surface-hopping simulations with a linear vibronic coupling model
reveal the competition of major intersystem crossing versus minor
internal conversion dynamics in an iron(II) N-heterocyclic carbene
dye. The triplet population bifurcates into two regions of the potential
energy surfaces, characterized by small and large static dipole moments
due to different electronic character and showing coherent oscillations
of 400 fs until both triplet populations coexist in a mixture of 60:40.
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Affiliation(s)
- J Patrick Zobel
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währingerstraße 19, 1090 Vienna, Austria
| | - Olga S Bokareva
- Institute of Physics, Rostock University, Albert Einstein Straße 23-24, 18059 Rostock, Germany
| | - Peter Zimmer
- Faculty of Science, Chemistry Department and Center for Sustainable Systems Design (CSSD), Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany
| | - Christoph Wölper
- Department for X-Ray Diffraction, Inorganic Chemistry, University of Duisburg-Essen, Universitätsstraße 7, D-45117 Essen, Germany
| | - Matthias Bauer
- Faculty of Science, Chemistry Department and Center for Sustainable Systems Design (CSSD), Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währingerstraße 19, 1090 Vienna, Austria.,Vienna Research Platform on Accelerating Photoreaction Discovery, University of Vienna, Währingerstr. 19, 1090 Vienna, Austria
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21
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Yu D, To WP, Tong GSM, Wu LL, Chan KT, Du L, Phillips DL, Liu Y, Che CM. Luminescent tungsten(vi) complexes as photocatalysts for light-driven C-C and C-B bond formation reactions. Chem Sci 2020; 11:6370-6382. [PMID: 32874518 PMCID: PMC7448528 DOI: 10.1039/d0sc01340d] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/23/2020] [Indexed: 12/13/2022] Open
Abstract
The realization of photocatalysis for practical synthetic application hinges on the development of inexpensive photocatalysts which can be prepared on a large scale. Herein an air-stable, visible-light-absorbing photoluminescent tungsten(vi) complex which can be conveniently prepared at the gram-scale is described. This complex could catalyse photochemical organic transformation reactions including borylation of aryl halides, such as aryl chloride, reductive coupling of benzyl bromides for C-C bond formation, reductive coupling of phenacyl bromides, and decarboxylative coupling of redox-active esters of alkyl carboxylic acid with high product yields and broad functional group tolerance.
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Affiliation(s)
- Daohong Yu
- Department of Chemistry , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , China .
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Wai-Pong To
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Glenna So Ming Tong
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Liang-Liang Wu
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Kaai-Tung Chan
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Lili Du
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - David Lee Phillips
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Yungen Liu
- Department of Chemistry , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , China .
| | - Chi-Ming Che
- Department of Chemistry , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , China .
- State Key Laboratory of Synthetic Chemistry , HKU-CAS Joint Laboratory on New Materials , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
- HKU Shenzhen Institute of Research and Innovation Shenzhen , Guangdong 518055 , China
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22
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Vukadinovic Y, Burkhardt L, Päpcke A, Miletic A, Fritsch L, Altenburger B, Schoch R, Neuba A, Lochbrunner S, Bauer M. When Donors Turn into Acceptors: Ground and Excited State Properties of FeII Complexes with Amine-Substituted Tridentate Bis-imidazole-2-ylidene Pyridine Ligands. Inorg Chem 2020; 59:8762-8774. [DOI: 10.1021/acs.inorgchem.0c00393] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Yannik Vukadinovic
- Department of Chemistry and Center for Sustainable Systems Design (CSSD), Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany
| | - Lukas Burkhardt
- Department of Chemistry and Center for Sustainable Systems Design (CSSD), Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany
| | - Ayla Päpcke
- Institute for Physics and Department of Life, Light and Matter, University of Rostock, 18051 Rostock, Germany
| | - Anabel Miletic
- Department of Chemistry and Center for Sustainable Systems Design (CSSD), Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany
| | - Lorena Fritsch
- Department of Chemistry and Center for Sustainable Systems Design (CSSD), Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany
| | - Björn Altenburger
- Institute for Physics and Department of Life, Light and Matter, University of Rostock, 18051 Rostock, Germany
| | - Roland Schoch
- Department of Chemistry and Center for Sustainable Systems Design (CSSD), Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany
| | - Adam Neuba
- Department of Chemistry and Center for Sustainable Systems Design (CSSD), Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany
| | - Stefan Lochbrunner
- Institute for Physics and Department of Life, Light and Matter, University of Rostock, 18051 Rostock, Germany
| | - Matthias Bauer
- Department of Chemistry and Center for Sustainable Systems Design (CSSD), Paderborn University, Warburger Straße 100, 33098 Paderborn, Germany
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23
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Gujt J, Zimmer P, Zysk F, Süß V, Felser C, Bauer M, Kühne TD. Water structure near the surface of Weyl semimetals as catalysts in photocatalytic proton reduction. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2020; 7:034101. [PMID: 32478126 PMCID: PMC7228780 DOI: 10.1063/4.0000008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 04/22/2020] [Indexed: 06/11/2023]
Abstract
In this work, second-generation Car-Parrinello-based mixed quantum-classical mechanics molecular dynamics simulations of small nanoparticles of NbP, NbAs, TaAs, and 1T-TaS2 in water are presented. The first three materials are topological Weyl semimetals, which were recently discovered to be active catalysts in photocatalytic water splitting. The aim of this research was to correlate potential differences in the water structure in the vicinity of the nanoparticle surface with the photocatalytic activity of these materials in light induced proton reduction. The results presented herein allow explaining the catalytic activity of these Weyl semimetals: the most active material, NbP, exhibits a particularly low water coordination near the surface of the nanoparticle, whereas for 1T-TaS2, with the lowest catalytic activity, the water structure at the surface is most ordered. In addition, the photocatalytic activity of several organic and metalorganic photosensitizers in the hydrogen evolution reaction was experimentally investigated with NbP as the proton reduction catalyst. Unexpectedly, the charge of the photosensitizer plays a decisive role for the photocatalytic performance.
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Affiliation(s)
- Jure Gujt
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany
| | - Peter Zimmer
- Department of Chemistry, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany
| | - Frederik Zysk
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany
| | - Vicky Süß
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187 Dresden, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187 Dresden, Germany
| | - Matthias Bauer
- Department of Chemistry, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany
| | - Thomas D. Kühne
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany
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24
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Photophysics and Photochemistry of Iron Carbene Complexes for Solar Energy Conversion and Photocatalysis. Catalysts 2020. [DOI: 10.3390/catal10030315] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Earth-abundant first row transition metal complexes are important for the development of large-scale photocatalytic and solar energy conversion applications. Coordination compounds based on iron are especially interesting, as iron is the most common transition metal element in the Earth’s crust. Unfortunately, iron-polypyridyl and related traditional iron-based complexes generally suffer from poor excited state properties, including short excited-state lifetimes, that make them unsuitable for most light-driven applications. Iron carbene complexes have emerged in the last decade as a new class of coordination compounds with significantly improved photophysical and photochemical properties, that make them attractive candidates for a range of light-driven applications. Specific aspects of the photophysics and photochemistry of these iron carbenes discussed here include long-lived excited state lifetimes of charge transfer excited states, capabilities to act as photosensitizers in solar energy conversion applications like dye-sensitized solar cells, as well as recent demonstrations of promising progress towards driving photoredox and photocatalytic processes. Complementary advances towards photofunctional systems with both Fe(II) complexes featuring metal-to-ligand charge transfer excited states, and Fe(III) complexes displaying ligand-to-metal charge transfer excited states are discussed. Finally, we outline emerging opportunities to utilize the improved photochemical properties of iron carbenes and related complexes for photovoltaic, photoelectrochemical and photocatalytic applications.
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25
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Abstract
The use of iron in photoactive metal complexes has been investigated for decades. In this respect, the charge transfer (CT) states are of particular interest, since they are usually responsible for the photofunctionality of such compounds. However, only recently breakthroughs have been made in extending CT excited state lifetimes that are notoriously short-lived in classical polypyridine iron coordination compounds. This success is in large parts owed to the use of strongly σ-donating N-heterocyclic carbene (NHC) ligands that help manipulating the photophysical and photochemical properties of iron complexes. In this review we aim to map out the basic design principles for the generation of photofunctional iron NHC complexes, summarize the progress made so far and recapitulate on the synthetic methods used. Further, we want to highlight the challenges still existing and give inspiration for future generations of photoactive iron complexes.
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26
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Kalinko A, Caliebe WA, Schoch R, Bauer M. A von Hamos-type hard X-ray spectrometer at the PETRA III beamline P64. JOURNAL OF SYNCHROTRON RADIATION 2020; 27:31-36. [PMID: 31868733 PMCID: PMC6927517 DOI: 10.1107/s1600577519013638] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 10/05/2019] [Indexed: 05/20/2023]
Abstract
The design and performance of the high-resolution wavelength-dispersive multi-crystal von Hamos-type spectrometer at PETRA III beamline P64 are described. Extended analyzer crystal collection available at the beamline allows coverage of a broad energy range from 5 keV to 20 keV with an energy resolution of 0.35-1 eV. Particular attention was paid to enabling two-color measurements by a combination of two types of analyzer crystals and two two-dimensional detectors. The performance of the spectrometer is demonstrated by elastic-line and emission-line measurements on various compounds.
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Affiliation(s)
- Aleksandr Kalinko
- Department Chemie and Center for Sustainable Systems Design (CSSD), Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
- Photon Science DESY, Notkestraße 85, 22607 Hamburg, Germany
| | | | - Roland Schoch
- Department Chemie and Center for Sustainable Systems Design (CSSD), Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | - Matthias Bauer
- Department Chemie and Center for Sustainable Systems Design (CSSD), Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
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27
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Tatsuno H, Kjær KS, Kunnus K, Harlang TCB, Timm C, Guo M, Chàbera P, Fredin LA, Hartsock RW, Reinhard ME, Koroidov S, Li L, Cordones AA, Gordivska O, Prakash O, Liu Y, Laursen MG, Biasin E, Hansen FB, Vester P, Christensen M, Haldrup K, Németh Z, Sárosiné Szemes D, Bajnóczi É, Vankó G, Van Driel TB, Alonso‐Mori R, Glownia JM, Nelson S, Sikorski M, Lemke HT, Sokaras D, Canton SE, Dohn AO, Møller KB, Nielsen MM, Gaffney KJ, Wärnmark K, Sundström V, Persson P, Uhlig J. Hot Branching Dynamics in a Light‐Harvesting Iron Carbene Complex Revealed by Ultrafast X‐ray Emission Spectroscopy. Angew Chem Int Ed Engl 2019; 59:364-372. [DOI: 10.1002/anie.201908065] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/17/2019] [Indexed: 12/13/2022]
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28
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Tatsuno H, Kjær KS, Kunnus K, Harlang TCB, Timm C, Guo M, Chàbera P, Fredin LA, Hartsock RW, Reinhard ME, Koroidov S, Li L, Cordones AA, Gordivska O, Prakash O, Liu Y, Laursen MG, Biasin E, Hansen FB, Vester P, Christensen M, Haldrup K, Németh Z, Sárosiné Szemes D, Bajnóczi É, Vankó G, Van Driel TB, Alonso‐Mori R, Glownia JM, Nelson S, Sikorski M, Lemke HT, Sokaras D, Canton SE, Dohn AO, Møller KB, Nielsen MM, Gaffney KJ, Wärnmark K, Sundström V, Persson P, Uhlig J. Hot Branching Dynamics in a Light‐Harvesting Iron Carbene Complex Revealed by Ultrafast X‐ray Emission Spectroscopy. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201908065] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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29
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Steube J, Burkhardt L, Päpcke A, Moll J, Zimmer P, Schoch R, Wölper C, Heinze K, Lochbrunner S, Bauer M. Excited‐State Kinetics of an Air‐Stable Cyclometalated Iron(II) Complex. Chemistry 2019; 25:11826-11830. [DOI: 10.1002/chem.201902488] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Jakob Steube
- Institute of Inorganic Chemistry and Center for Sustainable, Systems Design (CSSD)University of Paderborn Warburger Straße 100 33098 Paderborn Germany
| | - Lukas Burkhardt
- Institute of Inorganic Chemistry and Center for Sustainable, Systems Design (CSSD)University of Paderborn Warburger Straße 100 33098 Paderborn Germany
| | - Ayla Päpcke
- Institute of Physics and Department of Life, Light and MatterUniversity of Rostock 18051 Rostock Germany
| | - Johannes Moll
- Institute of Inorganic Chemistry and Analytical ChemistryJohannes Gutenberg University Duesbergweg 10–14 55128 Mainz Germany
| | - Peter Zimmer
- Institute of Inorganic Chemistry and Center for Sustainable, Systems Design (CSSD)University of Paderborn Warburger Straße 100 33098 Paderborn Germany
| | - Roland Schoch
- Institute of Inorganic Chemistry and Center for Sustainable, Systems Design (CSSD)University of Paderborn Warburger Straße 100 33098 Paderborn Germany
| | - Christoph Wölper
- Institute for Inorganic Chemistry and Center for Nanointegration, Duisburg-Essen (Cenide)University of Duisburg-Essen Universitätsstraße 5-7 45117 Essen Germany
| | - Katja Heinze
- Institute of Inorganic Chemistry and Analytical ChemistryJohannes Gutenberg University Duesbergweg 10–14 55128 Mainz Germany
| | - Stefan Lochbrunner
- Institute of Physics and Department of Life, Light and MatterUniversity of Rostock 18051 Rostock Germany
| | - Matthias Bauer
- Institute of Inorganic Chemistry and Center for Sustainable, Systems Design (CSSD)University of Paderborn Warburger Straße 100 33098 Paderborn Germany
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30
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31
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Ligand acidity constants as calculated by density functional theory for PF3 and N-Heterocyclic carbene ligands in hydride complexes of Iron(II). J Organomet Chem 2019. [DOI: 10.1016/j.jorganchem.2018.10.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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32
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Hakey BM, Darmon JM, Zhang Y, Petersen JL, Milsmann C. Synthesis and Electronic Structure of Neutral Square-Planar High-Spin Iron(II) Complexes Supported by a Dianionic Pincer Ligand. Inorg Chem 2019; 58:1252-1266. [PMID: 30608668 DOI: 10.1021/acs.inorgchem.8b02730] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Two square-planar high-spin FeII complexes bearing a dianionic pyridine dipyrrolate pincer ligand and a diethyl ether or tetrahydrofuran ligand were synthesized and structurally characterized, and their electronic structures were elucidated by a combined spectroscopic and computational approach. In contrast to previous examples, the S = 2 ground states of these square-planar FeII complexes do not require an overall anionic charge of the compounds or incorporation of alkali metal cations. The tetrahydrofuran complex exhibits an equilibrium between four- and five-coordinate species in solution, which was supported by 1H NMR and 57Fe Mössbauer spectroscopy and comparison to a structurally characterized five-coordinate pyridine dipyrrolate iron bis-pyridine adduct. A detailed computational analysis of the electronic structures of the four- and five-coordinate species via density functional theory provides insight into the origins of the unusual ground state configurations for FeII in a square-planar ligand field and explains the associated characteristic spectroscopic parameters.
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Affiliation(s)
- Brett M Hakey
- C. Eugene Bennett Department of Chemistry , West Virginia University , 100 Prospect Street , Morgantown , West Virginia 26506 , United States
| | - Jonathan M Darmon
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| | - Yu Zhang
- C. Eugene Bennett Department of Chemistry , West Virginia University , 100 Prospect Street , Morgantown , West Virginia 26506 , United States
| | - Jeffrey L Petersen
- C. Eugene Bennett Department of Chemistry , West Virginia University , 100 Prospect Street , Morgantown , West Virginia 26506 , United States
| | - Carsten Milsmann
- C. Eugene Bennett Department of Chemistry , West Virginia University , 100 Prospect Street , Morgantown , West Virginia 26506 , United States
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33
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Zimmer P, Burkhardt L, Schepper R, Zheng K, Gosztola D, Neuba A, Flörke U, Wölper C, Schoch R, Gawelda W, Canton SE, Bauer M. Towards Noble-Metal-Free Dyads: Ground and Excited State Tuning by a Cobalt Dimethylglyoxime Motif Connected to an Iron N-Heterocyclic Carbene Photosensitizer. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201800946] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Peter Zimmer
- Faculty of science; Paderborn University; Warburger Straße 100 33098 Paderborn Germany
| | - Lukas Burkhardt
- Faculty of science; Paderborn University; Warburger Straße 100 33098 Paderborn Germany
| | - Rahel Schepper
- Faculty of science; Paderborn University; Warburger Straße 100 33098 Paderborn Germany
| | - Kaibo Zheng
- Department of Chemistry; Technical University of Denmark; -2800 Kongens Lyngby Denmark
- Department of Chemical Physics and NanoLund; Lund University; Box 124 22100 Lund Sweden
| | - David Gosztola
- Argonne National Laboratory; Center for Nanoscale Materials; 9700 S. Cass Avenue 60439 Lemont, Illinois United States
| | - Adam Neuba
- Faculty of science; Paderborn University; Warburger Straße 100 33098 Paderborn Germany
| | - Ulrich Flörke
- Faculty of science; Paderborn University; Warburger Straße 100 33098 Paderborn Germany
| | - Christoph Wölper
- Institute for Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (Cenide); University of Duisburg-Essen; Universitätsstraße 5-7 -45117 Essen Germany
| | - Roland Schoch
- Faculty of science; Paderborn University; Warburger Straße 100 33098 Paderborn Germany
| | - Wojciech Gawelda
- European XFEL, Holzkoppel 4; 22869 Schenefeld Germany
- Faculty of Physics; Adam Mickiewicz University, Umultowska 85, 61-614 Poznań; Poland
| | - Sophie E. Canton
- ELI-ALPS, ELI-HU Non-Profit Ltd., Dugonics ter 13, Szeged 6720, Hungary & Attosecond Science Group, Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85; Germany
| | - Matthias Bauer
- Faculty of science; Paderborn University; Warburger Straße 100 33098 Paderborn Germany
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34
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Grübel M, Bosque I, Altmann PJ, Bach T, Hess CR. Redox and photocatalytic properties of a Ni II complex with a macrocyclic biquinazoline (Mabiq) ligand. Chem Sci 2018; 9:3313-3317. [PMID: 29780460 PMCID: PMC5932533 DOI: 10.1039/c7sc05320g] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 02/20/2018] [Indexed: 01/04/2023] Open
Abstract
We present a late, first row transition metal photosensitizer that promotes photocatalytic C-C bond formation. The title compound, [Ni(Mabiq)]OTf, as well as its one-electron reduced form, Ni(Mabiq), were synthesized and molecular structures of both were obtained. The electronic structure of the reduced complex additionally was characterized by spectroscopic and DFT computational methods. Notably, [NiII(Mabiq)]OTf is photoactive: reduction of the compound was achieved photochemically upon irradiation at λ = 457 nm and reductive quenching by NEt3. The performance of [Ni(Mabiq)]OTf as a photoredox catalyst was examined in the cyclization of a bromoalkyl-substituted indole. In this reaction, the first-row transition metal compound is comparable if not superior to [Ru(bpy)3]2+ in terms of efficiency (turnover number) and chemoselectivity. Studies using a series of sacrificial donor amines indicate that the excited state redox potential of [Ni(Mabiq)]+* is ≥1.25 V vs. SCE. This value is similar to the excited state potential of commonly employed noble metal based photocatalysts. The Ni-Mabiq compound thus provides a rare example of an earth-abundant photoredox catalyst.
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Affiliation(s)
- Michael Grübel
- Department of Chemistry , Catalysis Research Center (CRC) , Technische Universität München , 85747 Garching , Germany . ;
| | - Irene Bosque
- Department of Chemistry , Catalysis Research Center (CRC) , Technische Universität München , 85747 Garching , Germany . ;
| | - Philipp J Altmann
- Department of Chemistry , Catalysis Research Center (CRC) , Technische Universität München , 85747 Garching , Germany . ;
| | - Thorsten Bach
- Department of Chemistry , Catalysis Research Center (CRC) , Technische Universität München , 85747 Garching , Germany . ;
| | - Corinna R Hess
- Department of Chemistry , Catalysis Research Center (CRC) , Technische Universität München , 85747 Garching , Germany . ;
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35
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Büldt LA, Wenger OS. Luminescent complexes made from chelating isocyanide ligands and earth-abundant metals. Dalton Trans 2018; 46:15175-15177. [PMID: 29063087 DOI: 10.1039/c7dt03620e] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In this invited frontier article, recently discovered d6 and d10 complexes with long-lived metal-to-ligand charge transfer (MLCT) excited states are highlighted. Chelating diisocyanide ligands give access to emissive Mo(0) and Cr(0) complexes with d6 electron configuration exhibiting photophysical properties similar to those of Ru(ii) polypyridines or cyclometalated Ir(iii) complexes. With Ni(0), these ligands yield luminescent tetrahedral d10 complexes similar to isoelectronic Cu(i) bis(diimine) compounds.
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Affiliation(s)
- Laura A Büldt
- Department of Chemistry, University of Basel, St Johanns-Ring 19, 4056 Basel, Switzerland.
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36
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Zimmer P, Burkhardt L, Friedrich A, Steube J, Neuba A, Schepper R, Müller P, Flörke U, Huber M, Lochbrunner S, Bauer M. The Connection between NHC Ligand Count and Photophysical Properties in Fe(II) Photosensitizers: An Experimental Study. Inorg Chem 2017; 57:360-373. [DOI: 10.1021/acs.inorgchem.7b02624] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Peter Zimmer
- Department
Chemie, Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | - Lukas Burkhardt
- Department
Chemie, Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | - Aleksej Friedrich
- Institute
of Physics, University of Rostock, Albert-Einstein-Str. 23, 18059 Rostock, Germany
| | - Jakob Steube
- Department
Chemie, Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | - Adam Neuba
- Department
Chemie, Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | - Rahel Schepper
- Department
Chemie, Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | - Patrick Müller
- Department
Chemie, Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | - Ulrich Flörke
- Department
Chemie, Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | - Marina Huber
- Department
Chemie, Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | - Stefan Lochbrunner
- Institute
of Physics, University of Rostock, Albert-Einstein-Str. 23, 18059 Rostock, Germany
| | - Matthias Bauer
- Department
Chemie, Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
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37
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Larsen CB, Wenger OS. Photoredox Catalysis with Metal Complexes Made from Earth-Abundant Elements. Chemistry 2017; 24:2039-2058. [PMID: 28892199 DOI: 10.1002/chem.201703602] [Citation(s) in RCA: 227] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/08/2017] [Indexed: 01/14/2023]
Abstract
Photoredox chemistry with metal complexes as sensitizers and catalysts frequently relies on precious elements such as ruthenium or iridium. Over the past 5 years, important progress towards the use of complexes made from earth-abundant elements in photoredox catalysis has been made. This review summarizes the advances made with photoactive CrIII , FeII , CuI , ZnII , ZrIV , Mo0 , and UVI complexes in the context of synthetic organic photoredox chemistry using visible light as an energy input. Mechanistic considerations are combined with discussions of reaction types and scopes. Perspectives for the future of the field are discussed against the background of recent significant developments of new photoactive metal complexes made from earth-abundant elements.
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Affiliation(s)
- Christopher B Larsen
- Department of Chemistry, University of Basel, St Johanns-Ring 19, Basel, 4056, Switzerland
| | - Oliver S Wenger
- Department of Chemistry, University of Basel, St Johanns-Ring 19, Basel, 4056, Switzerland
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38
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Büldt LA, Wenger OS. Chromium complexes for luminescence, solar cells, photoredox catalysis, upconversion, and phototriggered NO release. Chem Sci 2017; 8:7359-7367. [PMID: 29163886 PMCID: PMC5672834 DOI: 10.1039/c7sc03372a] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/04/2017] [Indexed: 12/15/2022] Open
Abstract
Cr(iii) and Cr(0) complexes are earth-abundant alternatives to photosensitizers that are commonly made from precious metals.
Some complexes of Cr(iii) and Cr(0) have long been known to exhibit interesting photophysical and photochemical properties, but in the past few years important conceptual progress was made. This Perspective focuses on the recent developments of Cr(iii) complexes as luminophores and dyes for solar cells, their application in photoredox catalysis, their use as sensitizers in upconversion processes, and their performance as photochemical nitric oxide sources. The example of a luminescent Cr(0) isocyanide complex illustrates the possibility of obtaining photoactive analogues of d6 metal complexes that are commonly made from precious metals such as Ru(ii) or Ir(iii). The studies highlighted herein illustrate the favorable excited-state properties of robust first-row transition metal complexes with broad application potential.
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Affiliation(s)
- Laura A Büldt
- Department of Chemistry , University of Basel , St. Johanns-Ring 19 , 4056 Basel , Switzerland .
| | - Oliver S Wenger
- Department of Chemistry , University of Basel , St. Johanns-Ring 19 , 4056 Basel , Switzerland .
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39
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Otto S, Nauth AM, Ermilov E, Scholz N, Friedrich A, Resch-Genger U, Lochbrunner S, Opatz T, Heinze K. Photo-Chromium: Sensitizer for Visible-Light-Induced Oxidative C−H Bond Functionalization-Electron or Energy Transfer? CHEMPHOTOCHEM 2017. [DOI: 10.1002/cptc.201700077] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Sven Otto
- Institute of Inorganic and Analytical Chemistry; Johannes Gutenberg University of Mainz; Duesbergweg 10-14 55128 Mainz Germany
- Graduate School Materials Science in Mainz; Staudingerweg 9 55128 Mainz Germany
| | - Alexander M. Nauth
- Institute of Organic Chemistry; Johannes Gutenberg University of Mainz; Duesbergweg 10-14 55128 Mainz Germany
| | - Eugenyi Ermilov
- Division 1.10; Federal Institute for Materials Research and Testing (BAM); Richard-Willstätter-Str. 11 12489 Berlin Germany
| | - Norman Scholz
- Division 1.10; Federal Institute for Materials Research and Testing (BAM); Richard-Willstätter-Str. 11 12489 Berlin Germany
| | - Aleksej Friedrich
- Institute of Physics, University of Rostock; Albert-Einstein-Str. 23 18059 Rostock Germany
| | - Ute Resch-Genger
- Division 1.10; Federal Institute for Materials Research and Testing (BAM); Richard-Willstätter-Str. 11 12489 Berlin Germany
| | - Stefan Lochbrunner
- Institute of Physics, University of Rostock; Albert-Einstein-Str. 23 18059 Rostock Germany
| | - Till Opatz
- Institute of Organic Chemistry; Johannes Gutenberg University of Mainz; Duesbergweg 10-14 55128 Mainz Germany
| | - Katja Heinze
- Institute of Inorganic and Analytical Chemistry; Johannes Gutenberg University of Mainz; Duesbergweg 10-14 55128 Mainz Germany
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40
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Mengel AKC, Bissinger C, Dorn M, Back O, Förster C, Heinze K. Boosting Vis/NIR Charge-Transfer Absorptions of Iron(II) Complexes by N-Alkylation and N-Deprotonation in the Ligand Backbone. Chemistry 2017; 23:7920-7931. [PMID: 28383155 DOI: 10.1002/chem.201700959] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Indexed: 11/08/2022]
Abstract
Reversing the metal-to-ligand charge transfer (3 MLCT)/metal-centered (3 MC) excited state order in iron(II) complexes is a challenging objective, yet would finally result in long-sought luminescent transition-metal complexes with an earth-abundant central ion. One approach to achieve this goal is based on low-energy charge-transfer absorptions in combination with a strong ligand field. Coordinating electron-rich and electron-poor tridentate oligopyridine ligands with large bite angles at iron(II) enables both low-energy MLCT absorption bands around 590 nm and a strong ligand field. Variations of the electron-rich ligand by introducing longer alkyl substituents destabilizes the iron(II) complex towards ligand substitution reactions while hardly affecting the optical properties. On the other hand, N-deprotonation of the ligand backbone is feasible and reversible, yielding deep-green complexes with charge-transfer bands extending into the near-IR region. Time-dependent density functional theory calculations assign these absorption bands to transitions with dipole-allowed ligand-to-ligand charge transfer character. This unique geometric and electronic situation establishes a further regulating screw to increase the energy gap between potentially emitting charge-transfer states and the non-radiative ligand field states of iron(II) dyes.
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Affiliation(s)
- Andreas K C Mengel
- Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg University of Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Christian Bissinger
- Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg University of Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Matthias Dorn
- Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg University of Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Oliver Back
- Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg University of Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Christoph Förster
- Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg University of Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Katja Heinze
- Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg University of Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
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Büldt LA, Wenger OS. Isocyanid-Komplexe von Cr0
, Mo0
und W0
als Leuchtstoffe und Photosensibilisatoren mit langlebigen angeregten Zuständen. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201701210] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Laura A. Büldt
- Institut für Anorganische Chemie; Universität Tübingen; Auf der Morgenstelle 18 72076 Tübingen Deutschland
| | - Oliver S. Wenger
- Departement Chemie; Universität Basel; St. Johanns-Ring 19 4056 Basel Schweiz
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42
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Büldt LA, Wenger OS. Chromium(0), Molybdenum(0), and Tungsten(0) Isocyanide Complexes as Luminophores and Photosensitizers with Long-Lived Excited States. Angew Chem Int Ed Engl 2017; 56:5676-5682. [DOI: 10.1002/anie.201701210] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Indexed: 01/30/2023]
Affiliation(s)
- Laura A. Büldt
- Institute of Inorganic Chemistry; University of Tübingen; Auf der Morgenstelle 18 72076 Tübingen Germany
| | - Oliver S. Wenger
- Department of Chemistry; University of Basel; St. Johanns-Ring 19 4056 Basel Switzerland
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