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Zhang YK, Zhao L, Xie WJ, Li HR, He LN. Mononuclear Iron Pyridinethiolate Complex Promoted CO 2 Photoreduction via Rapid Intramolecular Electron Transfer. CHEMSUSCHEM 2024; 17:e202400090. [PMID: 38426643 DOI: 10.1002/cssc.202400090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/19/2024] [Accepted: 03/01/2024] [Indexed: 03/02/2024]
Abstract
Designing earth-abundant metal complexes as efficient molecular photocatalysts for visible light-driven CO2 reduction is a key challenge in artificial photosynthesis. Here, we demonstrated the first example of a mononuclear iron pyridine-thiolate complex that functions both as a photosensitizer and catalyst for CO2 reduction. This single-component bifunctional molecular photocatalyst efficiently reduced CO2 to formate and CO with a total turnover number (TON) of 46 and turnover frequency (TOF) of 11.5 h-1 in 4 h under visible light irradiation. Notably, the quantum yield was determined to be 8.4 % for the generation of formate and CO at 400 nm. Quenching experiments indicate that high photocatalytic activity is mainly attributed to the rapid intramolecular quenching protocol. The mechanism investigation by DFT calculation and electrochemical studies revealed that the protonation of Febpy(pyS)2 is indispensable step for photocatalytic CO2 reduction.
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Affiliation(s)
- Yong-Kang Zhang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China
| | - Lan Zhao
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China
| | - Wen-Jun Xie
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China
| | - Hong-Ru Li
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China
- College of Pharmacy, Nankai University, Tianjin, 300350, P. R. China
| | - Liang-Nian He
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China
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2
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Huss T, Dixon IM. Electronic Structure and Geometry of the Lowest 2LMCT State of Fe(III) Potential Fluorescent Emitters†. Inorg Chem 2023; 62:4284-4290. [PMID: 36852931 DOI: 10.1021/acs.inorgchem.2c04407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
Metal complexes with a 3d6 electron count are emerging as an alternative to 4d6-based photosensitizers, emitters, or photoredox catalysts. In recent years, several Fe(II) potential emitters have been proposed, based on strongly donating ligand sets. Those tend to facilitate oxidation to their 3d5 species, whose photophysics is based on low-lying ligand-to-metal charge-transfer (LMCT) states. The geometry and electronic structure of 2LMCT states are unveiled in this work.
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Affiliation(s)
- Tabea Huss
- Laboratoire de Chimie et Physique Quantiques, Universite de Toulouse, CNRS, Universite Toulouse III - Paul Sabatier, F-31062 Toulouse, France
| | - Isabelle M Dixon
- Laboratoire de Chimie et Physique Quantiques, Universite de Toulouse, CNRS, Universite Toulouse III - Paul Sabatier, F-31062 Toulouse, France
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3
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Sinha N, Wenger OS. Photoactive Metal-to-Ligand Charge Transfer Excited States in 3d 6 Complexes with Cr 0, Mn I, Fe II, and Co III. J Am Chem Soc 2023; 145:4903-4920. [PMID: 36808978 PMCID: PMC9999427 DOI: 10.1021/jacs.2c13432] [Citation(s) in RCA: 39] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Many coordination complexes and organometallic compounds with the 4d6 and 5d6 valence electron configurations have outstanding photophysical and photochemical properties, which stem from metal-to-ligand charge transfer (MLCT) excited states. This substance class makes extensive use of the most precious and least abundant metal elements, and consequently there has been a long-standing interest in first-row transition metal compounds with photoactive MLCT states. Semiprecious copper(I) with its completely filled 3d subshell is a relatively straightforward and well explored case, but in 3d6 complexes the partially filled d-orbitals lead to energetically low-lying metal-centered (MC) states that can cause undesirably fast MLCT excited state deactivation. Herein, we discuss recent advances made with isoelectronic Cr0, MnI, FeII, and CoIII compounds, for which long-lived MLCT states have become accessible over the past five years. Furthermore, we discuss possible future developments in the search for new first-row transition metal complexes with partially filled 3d subshells and photoactive MLCT states for next-generation applications in photophysics and photochemistry.
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Affiliation(s)
- Narayan Sinha
- 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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4
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Curtin GM, Jakubikova E. Extended π-Conjugated Ligands Tune Excited-State Energies of Iron(II) Polypyridine Dyes. Inorg Chem 2022; 61:18850-18860. [DOI: 10.1021/acs.inorgchem.2c02362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Gregory M. Curtin
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Elena Jakubikova
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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5
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Law KC, Tang Z, Wu L, Wan Q, To WP, Chang X, Low KH, Liu Y, Che CM. Cyclometalated Iron and Ruthenium Complexes Supported by a Tetradentate Ligand Scaffold with Mixed O, N, and C Donor Atoms: Synthesis, Structures, and Excited-State Properties. Organometallics 2022. [DOI: 10.1021/acs.organomet.1c00677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kwok-Chung Law
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Zhou Tang
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Liangliang Wu
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Qingyun Wan
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Wai-Pong To
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Xiaoyong Chang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Kam-Hung Low
- State Key Laboratory of Synthetic Chemistry and 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
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- HKU Shenzhen Institute of Research & Innovation, Shenzhen, Guangdong 518057, China
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6
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Cebrían C, Pastore M, Monari A, Assfeld X, Gros PC, Haacke S. Ultrafast Spectroscopy of Fe(II) Complexes Designed for Solar Energy Conversion: Current Status and Open Questions. Chemphyschem 2022; 23:e202100659. [DOI: 10.1002/cphc.202100659] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 01/22/2022] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | | | - Stefan Haacke
- University of Strasbourg: Universite de Strasbourg IPCMS 23, rue du Loess 67034 Strasbourg FRANCE
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7
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Magra K, Francés‐Monerris A, Cebrián C, Monari A, Haacke S, Gros PC. Bidentate Pyridyl‐NHC Ligands: Synthesis, Ground and Excited State Properties of Their Iron(II) Complexes and the Role of the fac/mer Isomerism. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100818] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Kévin Magra
- Université de Lorraine, CNRS, L2CM 57000 Metz France
| | | | | | - Antonio Monari
- Université de Lorraine, CNRS, LPCT 54000 Nancy France
- Université de de Paris and CNRS, Itodys 75006 Paris France
| | - Stefan Haacke
- Université de Strasbourg, CNRS, IPCMS 67000 Strasbourg France
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8
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Sárosiné Szemes D, Keszthelyi T, Papp M, Varga L, Vankó G. Quantum-chemistry-aided ligand engineering for potential molecular switches: changing barriers to tune excited state lifetimes. Chem Commun (Camb) 2020; 56:11831-11834. [PMID: 33021253 DOI: 10.1039/d0cc04467a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Substitution of terpyridine at the 4' position with electron withdrawing and donating groups is used to tune the quintet lifetime of its iron(ii) complex. DFT calculations suggest that the energy barrier between the quintet and singlet states can be altered significantly upon substitution, inducing a large variation of the lifetime of the photoexcited quintet state. This prediction was experimentally verified by transient optical absorption spectroscopy and good agreement with the trend expected from the calculations was found. This demonstrates that the potential energy landscape can indeed be rationally tailored by relevant modifications based on DFT predictions. This result should pave the way to advancing efficient theory-based ligand engineering of functional molecules to a wide range of applications.
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9
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Tang Z, Chang XY, Wan Q, Wang J, Ma C, Law KC, Liu Y, Che CM. Bis(tridentate) Iron(II) Complexes with a Cyclometalating Unit: Photophysical Property Enhancement with Combinatorial Strong Ligand Field Effect. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00149] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Zhou Tang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People’s Republic of China
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, People’s Republic of China
| | - Xiao-Yong Chang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People’s Republic of China
| | - Qingyun Wan
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, People’s Republic of China
| | - Jian Wang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People’s Republic of China
| | - Chensheng Ma
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong 518055, People’s Republic of China
| | - Kwok-Chung Law
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, People’s Republic of China
| | - Yungen Liu
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People’s Republic of China
| | - Chi-Ming Che
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People’s Republic of China
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, People’s Republic of China
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10
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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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11
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On the Possible Coordination on a 3MC State Itself? Mechanistic Investigation Using DFT-Based Methods. INORGANICS 2020. [DOI: 10.3390/inorganics8020015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Understanding light-induced ligand exchange processes is key to the design of efficient light-releasing prodrugs or photochemically driven functional molecules. Previous mechanistic investigations had highlighted the pivotal role of metal-centered (MC) excited states in the initial ligand loss step. The question remains whether they are equally important in the subsequent ligand capture step. This article reports the mechanistic study of direct acetonitrile coordination onto a 3MC state of [Ru(bpy)3]2+, leading to [Ru(bpy)2(κ1-bpy)(NCMe)]2+ in a 3MLCT (metal-to-ligand charge transfer) state. Coordination of MeCN is indeed accompanied by the decoordination of one pyridine ring of a bpy ligand. As estimated from Nudged Elastic Band calculations, the energy barrier along the minimum energy path is 20 kcal/mol. Interestingly, the orbital analysis conducted along the reaction path has shown that creation of the metallic vacancy can be achieved by reverting the energetic ordering of key dσ* and bpy-based π* orbitals, resulting in the change of electronic configuration from 3MC to 3MLCT. The approach of the NCMe lone pair contributes to destabilizing the dσ* orbital by electrostatic repulsion.
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12
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Francés‐Monerris A, Gros PC, Assfeld X, Monari A, Pastore M. Toward Luminescent Iron Complexes: Unravelling the Photophysics by Computing Potential Energy Surfaces. CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201900100] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Antonio Francés‐Monerris
- Laboratoire de Physique et Chimie Théoriques (LPCT)Université de Lorraine, CNRS 54000 Nancy France
| | - Philippe C. Gros
- Laboratoire Lorrain de Chimie Moléculaire (L2CM)Université de Lorraine, CNRS 54000 Nancy France
| | - Xavier Assfeld
- Laboratoire de Physique et Chimie Théoriques (LPCT)Université de Lorraine, CNRS 54000 Nancy France
| | - Antonio Monari
- Laboratoire de Physique et Chimie Théoriques (LPCT)Université de Lorraine, CNRS 54000 Nancy France
| | - Mariachiara Pastore
- Laboratoire de Physique et Chimie Théoriques (LPCT)Université de Lorraine, CNRS 54000 Nancy France
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13
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Wang J, Li C, Wong WL, Chow CF. Novel Iron-Based Polynuclear Metal Complexes [FeII(L)(CN)4]2–[FeIII(H2O)3Cl]2: Synthesis and Study of Photovoltaic Properties for Dye-Sensitized Solar Cell. RUSS J ELECTROCHEM+ 2019. [DOI: 10.1134/s1023193518140094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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15
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Ashley DC, Mukherjee S, Jakubikova E. Designing air-stable cyclometalated Fe(ii) complexes: stabilization via electrostatic effects. Dalton Trans 2019; 48:374-378. [DOI: 10.1039/c8dt04402c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Substitution of EWGs onto the cyclometelated iron complexes electrostatically stabilizes the Fe(ii) center while still preserving the increased ligand field strength.
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Affiliation(s)
| | | | - Elena Jakubikova
- Department of Chemistry
- North Carolina State University
- Raleigh
- USA
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16
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Chábera P, Fredin LA, Kjær KS, Rosemann NW, Lindh L, Prakash O, Liu Y, Wärnmark K, Uhlig J, Sundström V, Yartsev A, Persson P. Band-selective dynamics in charge-transfer excited iron carbene complexes. Faraday Discuss 2019; 216:191-210. [DOI: 10.1039/c8fd00232k] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A combination of ultrafast spectroscopy and DFT/TD-DFT calculations of a recently synthesised iron carbene complex elucidates the ultrafast excited state evolution processes in these systems.
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17
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Malladi S, Yarasi S, Sastry GN. Exploring the potential of iron to replace ruthenium in photosensitizers: a computational study. J Mol Model 2018; 24:341. [PMID: 30460519 DOI: 10.1007/s00894-018-3870-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 10/31/2018] [Indexed: 12/30/2022]
Abstract
In an effort to replace the widely used ruthenium metal complexes with low-cost, earth abundant iron complexes as photosensitizers for dye-sensitized solar cell (DSSC) applications, herein we report the computational design of heteroleptic iron complexes (FC1-3) coordinated with benzimidazole-phenylcarbene (C^N) ligands. DFT and TDDFT calculations predicted the stronger σ-donating and π-accepting nature of phenyl carbene ligands substituted with electron-withdrawing CF3, donating -N(CH3)2, and benzothiazine annulation than the imidazole carbene ligands (FC4); consequently, the metal-ligand bond distances and interactions that influence the ordering of charge transfer states with respect to metal centered states are altered in FC1-3 complexes. Detailed analysis based on energy decomposition analysis, spin density distribution analysis, and ab initio ligand field theory parameters were enabled to understand the nature of heteroleptic ligand interactions with the rest of the metal complex. The results from the study shed light on the judicious choice of ligands, as the same non-innocent ligand that is experimentally proven as favorable for Ru-dyes (TC1) is found to be detrimental for Fe-dyes (FC1). Among the complexes studied, the FC3 complex is a promising sensitizer for DSSC with 1,3MLCT energy level well separated from 3,5MC, thereby preventing the deactivation of MLCT. The outcome of the study is therefore an important step toward the development of photosensitizers based on iron metal. Graphical abstract Potential photosensitzers based on earth-abundant, low cost iron metal have been designed for dye sensitized solar cell applications.
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Affiliation(s)
- Srikanth Malladi
- Center for Molecular Modeling, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India
| | - Soujanya Yarasi
- Center for Molecular Modeling, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India. .,AcSIR - Academy of Scientific and Innovative Research, New Delhi, India.
| | - G Narahari Sastry
- Center for Molecular Modeling, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India. .,AcSIR - Academy of Scientific and Innovative Research, New Delhi, India.
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18
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Francés-Monerris A, Magra K, Darari M, Cebrián C, Beley M, Domenichini E, Haacke S, Pastore M, Assfeld X, Gros PC, Monari A. Synthesis and Computational Study of a Pyridylcarbene Fe(II) Complex: Unexpected Effects of fac/ mer Isomerism in Metal-to-Ligand Triplet Potential Energy Surfaces. Inorg Chem 2018; 57:10431-10441. [PMID: 30063338 DOI: 10.1021/acs.inorgchem.8b01695] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The synthesis and the steady-state absorption spectrum of a new pyridine-imidazolylidene Fe(II) complex (Fe-NHC) are presented. A detailed mechanism of the triplet metal-to-ligand charge-transfer states decay is provided on the basis of minimum energy path (MEP) calculations used to connect the lowest-lying singlet, triplet, and quintet state minima. The competition between the different decay pathways involved in the photoresponse is assessed by analyzing the shapes of the obtained potential energy surfaces. A qualitative difference between facial ( fac) and meridional ( mer) isomers' potential energy surface (PES) topologies is evidenced for the first time in iron-based complexes. Indeed, the mer complex shows a steeper triplet path toward the corresponding 3MC minimum, which lies at a lower energy as compared to the fac isomer, thus pointing to a faster triplet decay of the former. Furthermore, while a major role of the metal-centered quintet state population from the triplet 3MC region is excluded, we identify the enlargement of iron-nitrogen bonds as the main normal modes driving the excited-state decay.
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Affiliation(s)
| | - Kevin Magra
- Université de Lorraine , CNRS, L2CM , F57000 Metz , France
| | - Mohamed Darari
- Université de Lorraine , CNRS, L2CM , F54000 Nancy , France
| | | | - Marc Beley
- Université de Lorraine , CNRS, L2CM , F57000 Metz , France
| | | | - Stefan Haacke
- Université de Strasbourg-CNRS , UMR 7504 IPCMS , 67034 Strasbourg , France
| | | | - Xavier Assfeld
- Université de Lorraine , CNRS, LPCT , F54000 Nancy , France
| | | | - Antonio Monari
- Université de Lorraine , CNRS, LPCT , F54000 Nancy , France
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19
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Ashley DC, Jakubikova E. Ray-Dutt and Bailar Twists in Fe(II)-Tris(2,2′-bipyridine): Spin States, Sterics, and Fe–N Bond Strengths. Inorg Chem 2018; 57:5585-5596. [DOI: 10.1021/acs.inorgchem.8b00560] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Daniel C. Ashley
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Elena Jakubikova
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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20
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Kjær KS, Kunnus K, Harlang TCB, Van Driel TB, Ledbetter K, Hartsock RW, Reinhard ME, Koroidov S, Li L, Laursen MG, Biasin E, Hansen FB, Vester P, Christensen M, Haldrup K, Nielsen MM, Chabera P, Liu Y, Tatsuno H, Timm C, Uhlig J, Sundstöm V, Németh Z, Szemes DS, Bajnóczi É, Vankó G, Alonso-Mori R, Glownia JM, Nelson S, Sikorski M, Sokaras D, Lemke HT, Canton SE, Wärnmark K, Persson P, Cordones AA, Gaffney KJ. Solvent control of charge transfer excited state relaxation pathways in [Fe(2,2'-bipyridine)(CN) 4] 2. Phys Chem Chem Phys 2018; 20:4238-4249. [PMID: 29364300 DOI: 10.1039/c7cp07838b] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The excited state dynamics of solvated [Fe(bpy)(CN)4]2-, where bpy = 2,2'-bipyridine, show significant sensitivity to the solvent Lewis acidity. Using a combination of optical absorption and X-ray emission transient spectroscopies, we have previously shown that the metal to ligand charge transfer (MLCT) excited state of [Fe(bpy)(CN)4]2- has a 19 picosecond lifetime and no discernable contribution from metal centered (MC) states in weak Lewis acid solvents, such as dimethyl sulfoxide and acetonitrile.1,2 In the present work, we use the same combination of spectroscopic techniques to measure the MLCT excited state relaxation dynamics of [Fe(bpy)(CN)4]2- in water, a strong Lewis acid solvent. The charge-transfer excited state is now found to decay in less than 100 femtoseconds, forming a quasi-stable metal centered excited state with a 13 picosecond lifetime. We find that this MC excited state has triplet (3MC) character, unlike other reported six-coordinate Fe(ii)-centered coordination compounds, which form MC quintet (5MC) states. The solvent dependent changes in excited state non-radiative relaxation for [Fe(bpy)(CN)4]2- allows us to infer the influence of the solvent on the electronic structure of the complex. Furthermore, the robust characterization of the dynamics and optical spectral signatures of the isolated 3MC intermediate provides a strong foundation for identifying 3MC intermediates in the electronic excited state relaxation mechanisms of similar Fe-centered systems being developed for solar applications.
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Affiliation(s)
- Kasper S Kjær
- PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, USA.
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21
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Mukherjee S, Liu C, Jakubikova E. Comparison of Interfacial Electron Transfer Efficiency in [Fe(ctpy)2]2+–TiO2 and [Fe(cCNC)2]2+–TiO2 Assemblies: Importance of Conformational Sampling. J Phys Chem A 2018; 122:1821-1830. [DOI: 10.1021/acs.jpca.7b10932] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sriparna Mukherjee
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Chang Liu
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Elena Jakubikova
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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22
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Pastore M, Duchanois T, Liu L, Monari A, Assfeld X, Haacke S, Gros PC. Interfacial charge separation and photovoltaic efficiency in Fe(ii)-carbene sensitized solar cells. Phys Chem Chem Phys 2018; 18:28069-28081. [PMID: 27711638 DOI: 10.1039/c6cp05535d] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The first combined theoretical and photovoltaic characterization of both homoleptic and heteroleptic Fe(ii)-carbene sensitized photoanodes in working dye sensitized solar cells (DSSCs) has been performed. Three new heteroleptic Fe(ii)-NHC dye sensitizers have been synthesized, characterized and tested. Despite an improved interfacial charge separation in comparison to the homoleptic compounds, the heteroleptic complexes did not show boosted photovoltaic performances. The ab initio quantitative analysis of the interfacial electron and hole transfers and the measured photovoltaic data clearly evidenced fast recombination reactions for heteroleptics, even associated with un unfavorable directional electron flow, and hence slower injection rates, in the case of homoleptics. Notably, quantum mechanics calculations revealed that deprotonation of the not anchored carboxylic function in the homoleptic complex can effectively accelerate the electron injection rate and completely suppress the electron recombination to the oxidized dye. This result suggests that introduction of strong electron-donating substituents on the not-anchored carbene ligand in heteroleptic complexes, in such a way of mimicking the electronic effects of the carboxylate functionality, should yield markedly improved interfacial charge generation properties. The present results, providing for the first time a detailed understanding of the interfacial electron transfers and photovoltaic characterization in Fe(ii)-carbene sensitized solar cells, open the way to a rational molecular engineering of efficient iron-based dyes for photoelectrochemical applications.
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Affiliation(s)
- Mariachiara Pastore
- Université de Lorraine & CNRS, SRSMC, TMS, Boulevard des Aiguillettes, 54506 Vandoeuvre-lès-Nancy, France.
| | - Thibaut Duchanois
- Université de Lorraine & CNRS, SRSMC, HecRIn, Boulevard des Aiguillettes, 54506 Vandoeuvre-lès-Nancy, France.
| | - Li Liu
- Université de Strasbourg & CNRS, IPCMS & Labex NIE, Rue du Loess, 67034 Strasbourg Cedex, France
| | - Antonio Monari
- Université de Lorraine & CNRS, SRSMC, TMS, Boulevard des Aiguillettes, 54506 Vandoeuvre-lès-Nancy, France.
| | - Xavier Assfeld
- Université de Lorraine & CNRS, SRSMC, TMS, Boulevard des Aiguillettes, 54506 Vandoeuvre-lès-Nancy, France.
| | - Stefan Haacke
- Université de Strasbourg & CNRS, IPCMS & Labex NIE, Rue du Loess, 67034 Strasbourg Cedex, France
| | - Philippe C Gros
- Université de Lorraine & CNRS, SRSMC, HecRIn, Boulevard des Aiguillettes, 54506 Vandoeuvre-lès-Nancy, France.
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23
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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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24
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Mukherjee S, Torres DE, Jakubikova E. HOMO inversion as a strategy for improving the light-absorption properties of Fe(ii) chromophores. Chem Sci 2017; 8:8115-8126. [PMID: 29568460 PMCID: PMC5855294 DOI: 10.1039/c7sc02926h] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 10/03/2017] [Indexed: 12/26/2022] Open
Abstract
Substitution of π-conjugated donor groups onto the polypyridine ligands in Fe(ii) complexes inverts the HOMO character and improves the light-absorption.
A computational study of a series of [Fe(tpy)2]2+ (tpy = 2,2′:6′,2′′-terpyridine) complexes is reported, where the tpy ligand is substituted at the 4, 4′, and 4′′ positions by electron donor (furan, thiophene, selenophene, NH2) and acceptor (carboxylic acid, NO2) groups. Using DFT and TD-DFT calculations, we show that the substitution of heterocyclic π donor groups onto the tpy ligand scaffold leads to marked improvement of the [Fe(tpy)2]2+ absorption properties, characterized by increased molar extinction coefficients, shift of absorption energies to longer wavelengths, and broadening of the absorption spectrum in the visible region. The observed changes in the light absorption properties are due to destabilization of ligand-centered occupied π orbital energies, thus increasing the interactions between the metal t2g (HOMO) and ligand π orbitals. Substitution of extended π-conjugated groups, such as thienothiophene and dithienothiophene, further destabilizes the ligand π orbital energies, resulting in a fully ligand-localized HOMO (i.e., HOMO inversion) and additional improvement of the light absorption properties. These results open up a new strategy to tuning the light absorption properties of Fe(ii)-polypyridines.
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Affiliation(s)
- Sriparna Mukherjee
- Department of Chemistry , North Carolina State University , Raleigh , NC 27695 , USA .
| | - David E Torres
- Wake STEM Early College High School , 715 Barbour Dr , Raleigh , NC 27603 , USA
| | - Elena Jakubikova
- Department of Chemistry , North Carolina State University , Raleigh , NC 27695 , USA .
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25
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Ponseca CS, Chábera P, Uhlig J, Persson P, Sundström V. Ultrafast Electron Dynamics in Solar Energy Conversion. Chem Rev 2017; 117:10940-11024. [DOI: 10.1021/acs.chemrev.6b00807] [Citation(s) in RCA: 211] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Carlito S. Ponseca
- Division
of Chemical Physics, Chemical Center, and ‡Theoretical Chemistry Division,
Chemical Center, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Pavel Chábera
- Division
of Chemical Physics, Chemical Center, and ‡Theoretical Chemistry Division,
Chemical Center, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Jens Uhlig
- Division
of Chemical Physics, Chemical Center, and ‡Theoretical Chemistry Division,
Chemical Center, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Petter Persson
- Division
of Chemical Physics, Chemical Center, and ‡Theoretical Chemistry Division,
Chemical Center, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Villy Sundström
- Division
of Chemical Physics, Chemical Center, and ‡Theoretical Chemistry Division,
Chemical Center, Lund University, Box 124, Lund SE-221 00, Sweden
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26
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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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27
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Ashley DC, Jakubikova E. Ironing out the photochemical and spin-crossover behavior of Fe(II) coordination compounds with computational chemistry. Coord Chem Rev 2017. [DOI: 10.1016/j.ccr.2017.02.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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28
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Zimmer P, Müller P, Burkhardt L, Schepper R, Neuba A, Steube J, Dietrich F, Flörke U, Mangold S, Gerhards M, Bauer M. N-Heterocyclic Carbene Complexes of Iron as Photosensitizers for Light-Induced Water Reduction. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201700064] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Peter Zimmer
- Department Chemie; Universität Paderborn; Warburger Straße 100 33098 Paderborn Germany
| | - Patrick Müller
- Department Chemie; Universität Paderborn; Warburger Straße 100 33098 Paderborn Germany
| | - Lukas Burkhardt
- Department Chemie; Universität Paderborn; Warburger Straße 100 33098 Paderborn Germany
| | - Rahel Schepper
- Department Chemie; Universität Paderborn; Warburger Straße 100 33098 Paderborn Germany
| | - Adam Neuba
- Department Chemie; Universität Paderborn; Warburger Straße 100 33098 Paderborn Germany
| | - Jakob Steube
- Department Chemie; Universität Paderborn; Warburger Straße 100 33098 Paderborn Germany
| | - Fabian Dietrich
- Department of Chemistry and Research Center Optimas; TU Kaiserslautern; Erwin-Schrödinger-Straße 52 67663 Kaiserslautern Germany
| | - Ulrich Flörke
- Department Chemie; Universität Paderborn; Warburger Straße 100 33098 Paderborn Germany
| | - Stefan Mangold
- Synchrotron Radiation Facility ANKA; Karlsruhe Institute of Technology; Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
| | - Markus Gerhards
- Department of Chemistry and Research Center Optimas; TU Kaiserslautern; Erwin-Schrödinger-Straße 52 67663 Kaiserslautern Germany
| | - Matthias Bauer
- Department Chemie; Universität Paderborn; Warburger Straße 100 33098 Paderborn Germany
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29
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Fatur SM, Shepard SG, Higgins RF, Shores MP, Damrauer NH. A Synthetically Tunable System To Control MLCT Excited-State Lifetimes and Spin States in Iron(II) Polypyridines. J Am Chem Soc 2017; 139:4493-4505. [DOI: 10.1021/jacs.7b00700] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Steven M. Fatur
- Department
of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Samuel G. Shepard
- Department
of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Robert F. Higgins
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Matthew P. Shores
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Niels H. Damrauer
- Department
of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
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30
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Liu Y, Persson P, Sundström V, Wärnmark K. Fe N-Heterocyclic Carbene Complexes as Promising Photosensitizers. Acc Chem Res 2016; 49:1477-85. [PMID: 27455191 DOI: 10.1021/acs.accounts.6b00186] [Citation(s) in RCA: 162] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The photophysics and photochemistry of transition metal complexes (TMCs) has long been a hot field of interdisciplinary research. Rich metal-based redox processes, together with a high variety in electronic configurations and excited-state dynamics, have rendered TMCs excellent candidates for interconversion between light, chemical, and electrical energies in intramolecular, supramolecular, and interfacial arrangements. In specific applications such as photocatalytic organic synthesis, photoelectrochemical cells, and light-driven supramolecular motors, light absorption by a TMC-based photosensitizer and subsequent excited-state energy or electron transfer constitute essential steps. In this context, TMCs based on rare and expensive metals, such as ruthenium and iridium, are frequently employed as photosensitizers, which is obviously not ideal for large-scale implementation. In the search for abundant and environmentally benign solutions, six-coordinate Fe(II) complexes (Fe(II)L6) have been widely considered as highly desirable alternatives. However, not much success has been achieved due to the extremely short-lived triplet metal-to-ligand charge transfer ((3)MLCT) excited state that is deactivated by low-lying metal-centered (MC) states on a 100 fs time scale. A fundamental strategy to design useful Fe-based photosensitizers is thus to destabilize the MC states relative to the (3)MLCT state by increasing the ligand field strength, with special focus on making eg σ* orbitals on the Fe center energetically less accessible. Previous efforts to directly transplant successful strategies from Ru(II)L6 complexes unfortunately met with limited success in this regard, despite their close chemical kinship. In this Account, we summarize recent promising results from our and other groups in utilizing strongly σ-donating N-heterocyclic carbene (NHC) ligands to make strong-field Fe(II)L6 complexes with significantly extended (3)MLCT lifetimes. Already some of the first homoleptic bis(tridentate) complexes incorporating (CNHC^Npyridine^CNHC)-type ligands gratifyingly resulted in extension of the (3)MLCT lifetime by more than 2 orders of magnitude compared to the parental [Fe(tpy)2](2+) (tpy = 2,2':6',2″-terpyridine) complex. Quantum chemical (QC) studies also revealed that the (3)MC instead of the (5)MC state likely dictates the deactivation of the (3)MLCT state, a behavior distinct from traditional Fe(II)L6 complexes but rather resembling Ru analogues. A heteroleptic Fe(II) NHC complex featuring mesoionic bis(1,2,3-triazol-5-ylidene) (btz) ligands also delivered a 100-fold elongation of the (3)MLCT lifetime relative to its parental [Fe(bpy)3](2+) (bpy = 2,2'-bipyridine) complex. Again, a Ru-like deactivation mechanism of the (3)MLCT state was indicated by QC studies. With a COOH-functionalized homoleptic complex, a record (3)MLCT lifetime of 37 ps was recently observed on an Al2O3 nanofilm. As a proof of concept, it was further demonstrated that the significant improvement in the (3)MLCT lifetime indeed benefits efficient light harvesting with Fe(II) NHC complexes. For the first time, close-to-unity electron injection from the lowest-energy (3)MLCT state to a TiO2 nanofilm was achieved by a stable Fe(II) complex. This is in complete contrast to conventional Fe(II)L6-derived photosensitizers that could only make use of high-energy photons. These exciting results significantly broaden the understanding of the fundamental photophysics and photochemistry of d(6) Fe(II) complexes. They also open up new possibilities to develop solar energy-converting materials based on this abundant, inexpensive, and intrinsically nontoxic element.
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Affiliation(s)
- Yizhu Liu
- Centre
for Analysis and Synthesis, Lund University, Box 124, 22100 Lund, Sweden
- Department
of Chemical Physics, Lund University, Box 124, 22100 Lund, Sweden
| | - Petter Persson
- Theoretical
Chemistry Division, Lund University, Box 124, 22100 Lund, Sweden
| | - Villy Sundström
- Department
of Chemical Physics, Lund University, Box 124, 22100 Lund, Sweden
| | - Kenneth Wärnmark
- Centre
for Analysis and Synthesis, Lund University, Box 124, 22100 Lund, Sweden
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31
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Dixon IM, Boissard G, Whyte H, Alary F, Heully JL. Computational Estimate of the Photophysical Capabilities of Four Series of Organometallic Iron(II) Complexes. Inorg Chem 2016; 55:5089-91. [DOI: 10.1021/acs.inorgchem.6b00223] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Isabelle M. Dixon
- Laboratoire
de Chimie et
Physique Quantiques, UMR 5626 CNRS, Université Toulouse III Paul Sabatier, Toulouse 31062, France
| | - Gauthier Boissard
- Laboratoire
de Chimie et
Physique Quantiques, UMR 5626 CNRS, Université Toulouse III Paul Sabatier, Toulouse 31062, France
| | - Hannah Whyte
- Laboratoire
de Chimie et
Physique Quantiques, UMR 5626 CNRS, Université Toulouse III Paul Sabatier, Toulouse 31062, France
| | - Fabienne Alary
- Laboratoire
de Chimie et
Physique Quantiques, UMR 5626 CNRS, Université Toulouse III Paul Sabatier, Toulouse 31062, France
| | - Jean-Louis Heully
- Laboratoire
de Chimie et
Physique Quantiques, UMR 5626 CNRS, Université Toulouse III Paul Sabatier, Toulouse 31062, France
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32
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Fredin LA, Wärnmark K, Sundström V, Persson P. Molecular and Interfacial Calculations of Iron(II) Light Harvesters. CHEMSUSCHEM 2016; 9:667-675. [PMID: 27010851 DOI: 10.1002/cssc.201600062] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Indexed: 06/05/2023]
Abstract
Iron-carbene complexes show considerable promise as earth-abundant light-harvesters, and adsorption onto nanostructured TiO2 is a crucial step for developing solar energy applications. Intrinsic electron injection capabilities of such promising Fe(II) N-heterocyclic complexes (Fe-NHC) to TiO2 are calculated here, and found to correlate well with recent experimental findings of highly efficient interfacial injection. First, we examine the special bonding characteristics of Fe-NHC light harvesters. The excited-state surfaces are examined using density functional theory (DFT) and time-dependent DFT (TD-DFT) to explore relaxed excited-state properties. Finally, by relaxing an Fe-NHC adsorbed on a TiO2 nanocluster, we show favorable injection properties in terms of interfacial energy level alignment and electronic coupling suitable for efficient electron injection of excited electrons from the Fe complex into the TiO2 conduction band on ∼100 fs time scales.
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Affiliation(s)
- Lisa A Fredin
- Division of Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-22100, Lund, Sweden
| | - Kenneth Wärnmark
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-22100, Lund, Sweden
| | - Villy Sundström
- Division of Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-22100, Lund, Sweden
| | - Petter Persson
- Division of Theoretical Chemistry, Department of Chemistry, Lund University, Box 124, SE-22100, Lund, Sweden.
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33
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Shepard SG, Fatur SM, Rappé AK, Damrauer NH. Highly Strained Iron(II) Polypyridines: Exploiting the Quintet Manifold To Extend the Lifetime of MLCT Excited States. J Am Chem Soc 2016; 138:2949-52. [DOI: 10.1021/jacs.5b13524] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Samuel G. Shepard
- Department
of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Steven M. Fatur
- Department
of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Anthony K. Rappé
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Niels H. Damrauer
- Department
of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
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34
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Kreitner C, Heinze K. Excited state decay of cyclometalated polypyridine ruthenium complexes: insight from theory and experiment. Dalton Trans 2016; 45:13631-47. [DOI: 10.1039/c6dt01989g] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This perspective article tackles the open question why cyclometalated polypyridine ruthenium(ii) complexes typically only emit very weakly at room temperature and delivers answers beyond the standard schemes involving 3MC and tunneling decay channels.
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Affiliation(s)
- Christoph Kreitner
- Institute of Inorganic and Analytical Chemistry
- Johannes Gutenberg University
- D-55128 Mainz
- Germany
- Graduate School Materials Science in Mainz
| | - Katja Heinze
- Institute of Inorganic and Analytical Chemistry
- Johannes Gutenberg University
- D-55128 Mainz
- Germany
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35
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Iron sensitizer converts light to electrons with 92% yield. Nat Chem 2015; 7:883-9. [DOI: 10.1038/nchem.2365] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 09/02/2015] [Indexed: 12/25/2022]
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36
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Bowman DN, Bondarev A, Mukherjee S, Jakubikova E. Tuning the Electronic Structure of Fe(II) Polypyridines via Donor Atom and Ligand Scaffold Modifications: A Computational Study. Inorg Chem 2015; 54:8786-93. [DOI: 10.1021/acs.inorgchem.5b01409] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David N. Bowman
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Alexey Bondarev
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Sriparna Mukherjee
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Elena Jakubikova
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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37
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Duchanois T, Etienne T, Cebrián C, Liu L, Monari A, Beley M, Assfeld X, Haacke S, Gros PC. An Iron-Based Photosensitizer with Extended Excited-State Lifetime: Photophysical and Photovoltaic Properties. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500142] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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38
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Bowman DN, Mukherjee S, Barnes LJ, Jakubikova E. Linker dependence of interfacial electron transfer rates in Fe(II)-polypyridine sensitized solar cells. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:134205. [PMID: 25767105 DOI: 10.1088/0953-8984/27/13/134205] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Dye-sensitized solar cells (DSSCs) convert solar energy to electricity employing dye molecules attached to a semiconductor surface. Some of the most efficient DSSCs use Ru-based chromophores. Fe-based dyes represent a cheaper and more environmentally friendly alternative to these expensive and toxic dyes. The photoactive state of Fe-based chromophores responsible for charge-separation at the dye-semiconductor interface is, however, deactivated on a sub-picosecond time scale via the intersystem crossing (ISC) into a manifold of low-lying photo-inactive quintet states. Therefore, development of Fe-based dyes capable of fast interfacial electron transfer (IET) leading to efficient charge separation on a time scale competitive with the ISC events is important. This work investigates how linker groups anchoring a prototypical Fe-based dye [Fe(bpy-L)2(CN)2] (bpy = 2,2'-bipyridine, L = linker group) onto the TiO2 semiconductor surface influence the IET rates in the dye-semiconductor assemblies. Linker groups investigated include carboxylic acid, phosphonic acid, hydroxamate, catechol, and acetylacetonate. We employ time-dependent density functional theory (TD-DFT) to obtain absorption spectra of [Fe(bpy-L)2(CN)2] with each linker, and quantum dynamics simulations to investigate the IET rates between the dye and the (101) TiO2 anatase surface. For all attachments, TD-DFT calculations show similar absorption spectra with two main bands corresponding to the metal-to-ligand charge transfer transitions. The quantum dynamics simulations predict that the utilization of the hydroxamate linker instead of the commonly used carboxylic acid linker will lead to a more efficient IET and better photon-to-current conversion efficiencies in Fe(II)-polypyridine sensitized solar cells.
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Affiliation(s)
- David N Bowman
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
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39
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Dixon IM, Alary F, Boggio-Pasqua M, Heully JL. Reversing the relative 3MLCT–3MC order in Fe(ii) complexes using cyclometallating ligands: a computational study aiming at luminescent Fe(ii) complexes. Dalton Trans 2015; 44:13498-503. [DOI: 10.1039/c5dt01214g] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Positioning two cyclometallating rings on the periphery of tridentate ligands has allowed us to design for the first time an iron(ii) complex bearing the lowest triplet state of MLCT nature.
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Affiliation(s)
- Isabelle M. Dixon
- Laboratoire de Chimie et Physique Quantiques
- UMR 5626 CNRS/Université Paul Sabatier-Toulouse III
- Toulouse
- France
| | - Fabienne Alary
- Laboratoire de Chimie et Physique Quantiques
- UMR 5626 CNRS/Université Paul Sabatier-Toulouse III
- Toulouse
- France
| | - Martial Boggio-Pasqua
- Laboratoire de Chimie et Physique Quantiques
- UMR 5626 CNRS/Université Paul Sabatier-Toulouse III
- Toulouse
- France
| | - Jean-Louis Heully
- Laboratoire de Chimie et Physique Quantiques
- UMR 5626 CNRS/Université Paul Sabatier-Toulouse III
- Toulouse
- France
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40
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Mukherjee S, Bowman DN, Jakubikova E. Cyclometalated Fe(II) complexes as sensitizers in dye-sensitized solar cells. Inorg Chem 2014; 54:560-9. [PMID: 25531506 DOI: 10.1021/ic502438g] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Dye-sensitized solar cells (DSSCs) often utilize transition metal-based chromophores for light absorption and semiconductor sensitization. Ru(II)-based dyes are among the most commonly used sensitizers in DSSCs. As ruthenium is both expensive and rare, complexes based on cheaper and more abundant iron could serve as a good alternative. In this study, we investigate Fe(II)-bis(terpyridine) and its cyclometalated analogues, in which pyridine ligands are systematically replaced by aryl groups, as potential photosensitizers in DSSCs. We employ density functional theory at the B3LYP/6-31G*,SDD level to obtain the ground state electronic structure of these complexes. Quantum dynamics simulations are utilized to study interfacial electron transfer between the Fe(II) photosensitizers and a titanium dioxide semiconductor. We find that cyclometalation stabilizes the singlet ground state of these complexes by 8-19 kcal/mol but reduces the electron density on the carboxylic acid attached to the aryl ring. The results suggest that cyclometalation provides a feasible route to increasing the efficiency of Fe(II) photosensitizers but that care should be taken in choosing the substitution position for the semiconductor anchoring group.
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Affiliation(s)
- Sriparna Mukherjee
- Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695, United States
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41
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Liu Y, Kjaer KS, Fredin LA, Chábera P, Harlang T, Canton SE, Lidin S, Zhang J, Lomoth R, Bergquist KE, Persson P, Wärnmark K, Sundström V. A Heteroleptic Ferrous Complex with Mesoionic Bis(1,2,3-triazol-5-ylidene) Ligands: Taming the MLCT Excited State of Iron(II). Chemistry 2014; 21:3628-39. [DOI: 10.1002/chem.201405184] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Indexed: 11/08/2022]
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42
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Mengel AKC, Förster C, Breivogel A, Mack K, Ochsmann JR, Laquai F, Ksenofontov V, Heinze K. A Heteroleptic Push-Pull Substituted Iron(II) Bis(tridentate) Complex with Low-Energy Charge-Transfer States. Chemistry 2014; 21:704-14. [DOI: 10.1002/chem.201404955] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Indexed: 11/06/2022]
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43
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Dixon IM, Khan S, Alary F, Boggio-Pasqua M, Heully JL. Probing the photophysical capability of mono and bis(cyclometallated) Fe(ii) polypyridine complexes using inexpensive ground state DFT. Dalton Trans 2014; 43:15898-905. [DOI: 10.1039/c4dt01939c] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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44
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Duchanois T, Etienne T, Beley M, Assfeld X, Perpète EA, Monari A, Gros PC. Heteroleptic Pyridyl-Carbene Iron Complexes with Tuneable Electronic Properties. Eur J Inorg Chem 2014. [DOI: 10.1002/ejic.201402356] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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45
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Fredin LA, Pápai M, Rozsályi E, Vankó G, Wärnmark K, Sundström V, Persson P. Exceptional Excited-State Lifetime of an Iron(II)-N-Heterocyclic Carbene Complex Explained. J Phys Chem Lett 2014; 5:2066-71. [PMID: 26270494 DOI: 10.1021/jz500829w] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Earth-abundant transition-metal complexes are desirable for sensitizers in dye-sensitized solar cells or photocatalysts. Iron is an obvious choice, but the energy level structure of its typical polypyridyl complexes, featuring low-lying metal-centered states, has made such complexes useless as energy converters. Recently, we synthesized a novel iron-N-heterocyclic carbene complex exhibiting a remarkable 100-fold increase of the lifetime compared to previously known iron(II) complexes. Here, we rationalize the measured excited-state dynamics with DFT and TD-DFT calculations. The calculations show that the exceptionally long excited-state lifetime (∼9 ps) is achieved for this Fe complex through a significant destabilization of both triplet and quintet metal-centered scavenger states compared to other Fe(II) complexes. In addition, a shallow (3)MLCT potential energy surface with a low-energy transition path from the (3)MLCT to (3)MC and facile crossing from the (3)MC state to the ground state are identified as key features for the excited-state deactivation.
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Affiliation(s)
| | - Mátyás Pápai
- ‡Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
| | - Emese Rozsályi
- ‡Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
| | - György Vankó
- ‡Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
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