1
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Sinha N, Wellauer J, Maisuradze T, Prescimone A, Kupfer S, Wenger OS. Reversible Photoinduced Ligand Substitution in a Luminescent Chromium(0) Complex. J Am Chem Soc 2024; 146:10418-10431. [PMID: 38588581 PMCID: PMC11027151 DOI: 10.1021/jacs.3c13925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 03/13/2024] [Accepted: 03/19/2024] [Indexed: 04/10/2024]
Abstract
Light-triggered dissociation of ligands forms the basis for many compounds of interest for photoactivated chemotherapy (PACT), in which medicinally active substances are released or "uncaged" from metal complexes upon illumination. Photoinduced ligand dissociation is usually irreversible, and many recent studies performed in the context of PACT focused on ruthenium(II) polypyridines and related heavy metal complexes. Herein, we report a first-row transition metal complex, in which photoinduced dissociation and spontaneous recoordination of a ligand unit occurs. Two scorpionate-type tridentate chelates provide an overall six-coordinate arylisocyanide environment for chromium(0). Photoexcitation causes decoordination of one of these six ligating units and coordination of a solvent molecule, at least in tetrahydrofuran and 1,4-dioxane solvents, but far less in toluene, and below detection limit in cyclohexane. Transient UV-vis absorption spectroscopy and quantum chemical simulations point to photoinduced ligand dissociation directly from an excited metal-to-ligand charge-transfer state. Owing to the tridentate chelate design and the substitution lability of the first-row transition metal, recoordination of the photodissociated arylisocyanide ligand unit can occur spontaneously on a millisecond time scale. This work provides insight into possible self-healing mechanisms counteracting unwanted photodegradation processes and seems furthermore relevant in the contexts of photoswitching and (photo)chemical information storage.
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Affiliation(s)
- Narayan Sinha
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
- School
of Chemical Sciences, Indian Institute of
Technology Mandi, Mandi 175075, Himachal Pradesh, India
| | - Joël Wellauer
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Tamar Maisuradze
- Institute
of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Alessandro Prescimone
- Department
of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Stephan Kupfer
- Institute
of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Oliver S. Wenger
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
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2
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Prakash O, Chábera P, Kaul N, Hlynsson VF, Rosemann NW, Losada IB, Hoang Hai YT, Huang P, Bendix J, Ericsson T, Häggström L, Gupta AK, Strand D, Yartsev A, Lomoth R, Persson P, Wärnmark K. How Rigidity and Conjugation of Bidentate Ligands Affect the Geometry and Photophysics of Iron N-Heterocyclic Complexes: A Comparative Study. Inorg Chem 2024; 63:4461-4473. [PMID: 38421802 PMCID: PMC10934811 DOI: 10.1021/acs.inorgchem.3c03972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 02/07/2024] [Accepted: 02/08/2024] [Indexed: 03/02/2024]
Abstract
Two iron complexes featuring the bidentate, nonconjugated N-heterocyclic carbene (NHC) 1,1'-methylenebis(3-methylimidazol-2-ylidene) (mbmi) ligand, where the two NHC moieties are separated by a methylene bridge, have been synthesized to exploit the combined influence of geometric and electronic effects on the ground- and excited-state properties of homoleptic FeIII-hexa-NHC [Fe(mbmi)3](PF6)3 and heteroleptic FeII-tetra-NHC [Fe(mbmi)2(bpy)](PF6)2 (bpy = 2,2'-bipyridine) complexes. They are compared to the reported FeIII-hexa-NHC [Fe(btz)3](PF6)3 and FeII-tetra-NHC [Fe(btz)2(bpy)](PF6)2 complexes containing the conjugated, bidentate mesoionic NHC ligand 3,3'-dimethyl-1,1'-bis(p-tolyl)-4,4'-bis(1,2,3-triazol-5-ylidene) (btz). The observed geometries of [Fe(mbmi)3](PF6)3 and [Fe(mbmi)2(bpy)](PF6)2 are evaluated through L-Fe-L bond angles and ligand planarity and compared to those of [Fe(btz)3](PF6)3 and [Fe(btz)2(bpy)](PF6)2. The FeII/FeIII redox couples of [Fe(mbmi)3](PF6)3 (-0.38 V) and [Fe(mbmi)2(bpy)](PF6)2 (-0.057 V, both vs Fc+/0) are less reducing than [Fe(btz)3](PF6)3 and [Fe(btz)2(bpy)](PF6)2. The two complexes show intense absorption bands in the visible region: [Fe(mbmi)3](PF6)3 at 502 nm (ligand-to-metal charge transfer, 2LMCT) and [Fe(mbmi)2(bpy)](PF6)2 at 410 and 616 nm (metal-to-ligand charge transfer, 3MLCT). Lifetimes of 57.3 ps (2LMCT) for [Fe(mbmi)3](PF6)3 and 7.6 ps (3MLCT) for [Fe(mbmi)2(bpy)](PF6)2 were probed and are somewhat shorter than those for [Fe(btz)3](PF6)3 and [Fe(btz)2(bpy)](PF6)2. [Fe(mbmi)3](PF6)3 exhibits photoluminescence at 686 nm (2LMCT) in acetonitrile at room temperature with a quantum yield of (1.2 ± 0.1) × 10-4, compared to (3 ± 0.5) × 10-4 for [Fe(btz)3](PF6)3.
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Affiliation(s)
- Om Prakash
- Centre
for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
| | - Pavel Chábera
- Chemical
Physics Division, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
| | - Nidhi Kaul
- Department
of Chemistry − Ångström Laboratory, Uppsala University, Box
523, SE-751 20 Uppsala, Sweden
| | - Valtýr F. Hlynsson
- Centre
for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
| | - Nils W. Rosemann
- Chemical
Physics Division, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
| | - Iria Bolaño Losada
- Theoretical
Chemistry Division, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
| | - Yen Tran Hoang Hai
- Theoretical
Chemistry Division, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
| | - Ping Huang
- Department
of Chemistry − 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
| | - Tore Ericsson
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Lennart Häggström
- Department
of Physics − Ångström Laboratory, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden
| | - Arvind Kumar Gupta
- Centre
for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
| | - Daniel Strand
- Centre
for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
| | - Arkady Yartsev
- Chemical
Physics Division, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
| | - Reiner Lomoth
- Department
of Chemistry − Ångström Laboratory, Uppsala University, Box
523, SE-751 20 Uppsala, Sweden
| | - Petter Persson
- Theoretical
Chemistry Division, 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
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3
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Jin T, Wagner D, Wenger OS. Luminescent and Photoredox-Active Molybdenum(0) Complexes Competitive with Isoelectronic Ruthenium(II) Polypyridines. Angew Chem Int Ed Engl 2024; 63:e202314475. [PMID: 37885363 DOI: 10.1002/anie.202314475] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/25/2023] [Accepted: 10/25/2023] [Indexed: 10/28/2023]
Abstract
Ruthenium(II) complexes with chelating polypyridine ligands are among the most frequently investigated compounds in photophysics and photochemistry, owing to their favorable luminescence and photoredox properties. Equally good photoluminescence performance and attractive photocatalytic behavior is now achievable with isoelectronic molybdenum(0) complexes. The zero-valent oxidation state of molybdenum is stabilized by carbonyl or isocyanide ligands, and metal-to-ligand charge transfer (MLCT) excited states analogous to those in ruthenium(II) complexes can be established. Microsecond MLCT excited-state lifetimes and photoluminescence quantum yields up to 0.2 have been achieved in solution at room temperature, and the emission wavelength has become tunable over a large range. The molybdenum(0) complexes are stronger photoreductants than ruthenium(II) polypyridines and can therefore perform more challenging chemical reductions. The triplet nature of their luminescent MLCT states allows sensitization of photon upconversion via triplet-triplet annihilation, to convert low-energy input radiation into higher-energy output fluorescence. This review summarizes the current state of the art concerning luminescent molybdenum(0) complexes and highlights their application potential. Molybdenum is roughly 140 times more abundant and far cheaper than ruthenium, hence this research is relevant in the greater context of finding more sustainable alternatives to using precious and rare transition metals in photophysics and photochemistry.
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Affiliation(s)
- Tao Jin
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Dorothee Wagner
- 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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Wegeberg C, Häussinger D, Kupfer S, Wenger OS. Controlling the Photophysical Properties of a Series of Isostructural d 6 Complexes Based on Cr 0, Mn I, and Fe II. J Am Chem Soc 2024; 146:4605-4619. [PMID: 38334415 PMCID: PMC10885143 DOI: 10.1021/jacs.3c11580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Development of first-row transition metal complexes with similar luminescence and photoredox properties as widely used RuII polypyridines is attractive because metals from the first transition series are comparatively abundant and inexpensive. The weaker ligand field experienced by the valence d-electrons of first-row transition metals challenges the installation of the same types of metal-to-ligand charge transfer (MLCT) excited states as in precious metal complexes, due to rapid population of energetically lower-lying metal-centered (MC) states. In a family of isostructural tris(diisocyanide) complexes of the 3d6 metals Cr0, MnI, and FeII, the increasing effective nuclear charge and ligand field strength allow us to control the energetic order between the 3MLCT and 3MC states, whereas pyrene decoration of the isocyanide ligand framework provides control over intraligand (ILPyr) states. The chromium(0) complex shows red 3MLCT phosphorescence because all other excited states are higher in energy. In the manganese(I) complex, a microsecond-lived dark 3ILPyr state, reminiscent of the types of electronic states encountered in many polyaromatic hydrocarbon compounds, is the lowest and becomes photoactive. In the iron(II) complex, the lowest MLCT state has shifted to so much higher energy that 1ILPyr fluorescence occurs, in parallel to other excited-state deactivation pathways. Our combined synthetic-spectroscopic-theoretical study provides unprecedented insights into how effective nuclear charge, ligand field strength, and ligand π-conjugation affect the energetic order between MLCT and ligand-based excited states, and under what circumstances these individual states become luminescent and exploitable in photochemistry. Such insights are the key to further developments of luminescent and photoredox-active first-row transition metal complexes.
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Affiliation(s)
- Christina Wegeberg
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Daniel Häussinger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Stephan Kupfer
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Oliver S Wenger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
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5
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Yue M, He J, Zou C, Chang X, Lu W. Phosphorescent fac-Bis(triarylisocyanide) W(0) and Mo(0) Complexes. Inorg Chem 2024; 63:3267-3282. [PMID: 38307513 DOI: 10.1021/acs.inorgchem.3c03557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2024]
Abstract
Homoleptic W(0) and Mo(0) complexes containing bis(triarylisocyanide) ligands with bulky substituents were synthesized and spectroscopically characterized. Crystallographically determined structures revealed that these complexes are hourglass-like in shape with the tridentate ligands adopting a facial coordination mode to the metal center. These complexes luminesce in fluid solutions and in the solid state. Typically in toluene at 298 K, the two W(0) complexes display the emission maximum (lifetime and quantum yield) at 591 nm (0.83 μs and 0.35) and 628 nm (1.04 μs and 0.39), and similarly, the two Mo(0) complexes display it at 575 nm (0.54 μs and 0.15) and 617 nm (0.56 μs and 0.23). DFT and TDDFT calculations indicated that the low-energy absorption bands of the W(0) and Mo(0) complexes could be metal-to-ligand charge transfer (MLCT) transitions in nature. These complexes exhibited a reversible M+/0 redox couple at -0.70 and -0.63 V vs Fc+/0 for the W(0) complexes and -0.86 and -0.67 V for the Mo(0) complexes. The excited-state reduction potentials were hence estimated to be -2.91 and -2.74 V vs Fc+/0 for the W(0) complexes and -3.10 and -2.81 V vs Fc+/0 for the Mo(0) complexes, indicating that they are potentially strong photoreductants.
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Affiliation(s)
- Mengwei Yue
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, P. R. China
| | - Jiang He
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, P. R. China
| | - Chao Zou
- Songshan Lake Materials Laboratory, Functional Coordination Material Group-Frontier Research Center, Dongguan, Guangdong 523808, P. R. China
| | - Xiaoyong Chang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, P. R. China
| | - Wei Lu
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, P. R. China
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6
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Ye Y, Garrido-Barros P, Wellauer J, Cruz CM, Lescouëzec R, Wenger OS, Herrera JM, Jiménez JR. Luminescence and Excited-State Reactivity in a Heteroleptic Tricyanido Fe(III) Complex. J Am Chem Soc 2024; 146:954-960. [PMID: 38156951 PMCID: PMC10786067 DOI: 10.1021/jacs.3c11517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/07/2023] [Accepted: 12/08/2023] [Indexed: 01/03/2024]
Abstract
Harnessing sunlight via photosensitizing molecules is key for novel optical applications and solar-to-chemical energy conversion. Exploiting abundant metals such as iron is attractive but becomes challenging due to typically fast nonradiative relaxation processes. In this work, we report on the luminescence and excited-state reactivity of the heteroleptic [FeIII(pzTp)(CN)3]- complex (pzTp = tetrakis(pyrazolyl)borate), which incorporates a σ-donating trispyrazolyl chelate ligand and three monodentate σ-donating and π-accepting cyanide ligands. Contrary to the nonemissive [Fe(CN)6]3-, a broad emission band centered at 600 nm at room temperature has been recorded for the heteroleptic analogue attributed to the radiative deactivation from a 2LMCT excited state with a luminescence quantum yield of 0.02% and a lifetime of 80 ps in chloroform at room temperature. Bimolecular reactivity of the 2LMCT excited state was successfully applied to different alcohol photo-oxidation, identifying a cyanide-H bonding as a key reaction intermediate. Finally, this research demonstrated the exciting potential of [Fe(pzTp)(CN)3]- as a photo-oxidant, paving the way for further exploration and development of emissive Fe-based photosensitizers competent for photochemical transformations.
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Affiliation(s)
- Yating Ye
- Departamento
de Química Inorgánica, Facultad de Ciencias, Universidad de Granada and Unidad de Excelencia en
Química (UEQ), Avenida Fuente Nueva s/n, 18071, Granada, Spain
| | - Pablo Garrido-Barros
- Departamento
de Química Inorgánica, Facultad de Ciencias, Universidad de Granada and Unidad de Excelencia en
Química (UEQ), Avenida Fuente Nueva s/n, 18071, Granada, Spain
| | - Joël Wellauer
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Carlos M. Cruz
- Departamento
de Química Orgánica, Facultad de Ciencias, Universidad de Granada and Unidad de Excelencia en
Química (UEQ), Avenida Fuente Nueva s/n, 18071, Granada, Spain
| | - Rodrigue Lescouëzec
- Institut
Parisien de Chimie Moléculaire, CNRS, UMR 8232, Sorbonne Université, F-75252 Paris Cedex
5, France
| | - Oliver S. Wenger
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Juan Manuel Herrera
- Departamento
de Química Inorgánica, Facultad de Ciencias, Universidad de Granada and Unidad de Excelencia en
Química (UEQ), Avenida Fuente Nueva s/n, 18071, Granada, Spain
| | - Juan-Ramón Jiménez
- Departamento
de Química Inorgánica, Facultad de Ciencias, Universidad de Granada and Unidad de Excelencia en
Química (UEQ), Avenida Fuente Nueva s/n, 18071, Granada, Spain
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7
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Glaser F, Schmitz M, Kerzig C. Coulomb interactions for mediator-enhanced sensitized triplet-triplet annihilation upconversion in solution. NANOSCALE 2023; 16:123-137. [PMID: 38054748 DOI: 10.1039/d3nr05265f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Sensitized triplet-triplet annihilation upconversion offers an attractive possibility to replace a high-energy photon by two photons with lower energy through the combination of a light-harvesting triplet sensitizer and an annihilator for the formation of a fluorescent singlet state. Typically, high annihilator concentrations are required to achieve an efficient initial energy transfer and as a direct consequence the most highly energetic emission is often not detectable due to intrinsic reabsorption by the annihilator itself. Herein, we demonstrate that the addition of a charge-adapted mediator drastically improves the energy transfer efficiency at low annihilator concentrations via an energy transfer cascade. Inspired by molecular dyads and recent developments in nanocrystal-sensitized upconversion, our system exploits a concept to minimize intrinsic filter effects, while boosting the upconversion quantum yield in solution. A sensitizer-annihilator combination consisting of a ruthenium-based complex and 9,10-diphenylanthracene (DPA) is explored as model system and a sulfonated pyrene serves as mediator. The impact of opposite charges between sensitizer and mediator - to induce coulombic attraction and subsequently result in accelerated energy transfer rate constants - is analyzed in detail by different spectroscopic methods. Ion pairing and the resulting static energy transfer in both directions is a minor process, resulting in an improved overall performance. Finally, the more intense upconverted emission in the presence of the mediator is used to drive two catalytic photoreactions in a two-chamber setup, illustrating the advantages of our approach, in particular for photoreactions requiring oxygen that would interfere with the upconversion system.
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Affiliation(s)
- Felix Glaser
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
| | - Matthias Schmitz
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
| | - Christoph Kerzig
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
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8
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Kim D, Dang VQ, Teets TS. Improved transition metal photosensitizers to drive advances in photocatalysis. Chem Sci 2023; 15:77-94. [PMID: 38131090 PMCID: PMC10732135 DOI: 10.1039/d3sc04580c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 11/22/2023] [Indexed: 12/23/2023] Open
Abstract
To function effectively in a photocatalytic application, a photosensitizer's light absorption, excited-state lifetime, and redox potentials, both in the ground state and excited state, are critically important. The absorption profile is particularly relevant to applications involving solar harvesting, whereas the redox potentials and excited-state lifetimes determine the thermodynamics, kinetics, and quantum yields of photoinduced redox processes. This perspective article focuses on synthetic inorganic and organometallic approaches to optimize these three characteristics of transition-metal based photosensitizers. We include our own work in these areas, which has focused extensively on exceptionally strong cyclometalated iridium photoreductants that enable challenging reductive photoredox transformations on organic substrates, and more recent work which has led to improved solar harvesting in charge-transfer copper(i) chromophores, an emerging class of earth-abundant compounds particularly relevant to solar-energy applications. We also extensively highlight many other complementary strategies for optimizing these parameters and highlight representative examples from the recent literature. It remains a significant challenge to simultaneously optimize all three of these parameters at once, since improvements in one often come at the detriment of the others. These inherent trade-offs and approaches to obviate or circumvent them are discussed throughout.
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Affiliation(s)
- Dooyoung Kim
- University of Houston, Department of Chemistry 3585 Cullen Blvd. Room 112 Houston TX 77204-5003 USA
| | - Vinh Q Dang
- University of Houston, Department of Chemistry 3585 Cullen Blvd. Room 112 Houston TX 77204-5003 USA
| | - Thomas S Teets
- University of Houston, Department of Chemistry 3585 Cullen Blvd. Room 112 Houston TX 77204-5003 USA
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9
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Sinha N, Wegeberg C, Häussinger D, Prescimone A, Wenger OS. Photoredox-active Cr(0) luminophores featuring photophysical properties competitive with Ru(II) and Os(II) complexes. Nat Chem 2023; 15:1730-1736. [PMID: 37580444 PMCID: PMC10695827 DOI: 10.1038/s41557-023-01297-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 07/19/2023] [Indexed: 08/16/2023]
Abstract
Coordination complexes of precious metals with the d6 valence electron configuration such as Ru(II), Os(II) and Ir(III) are used for lighting applications, solar energy conversion and photocatalysis. Until now, d6 complexes made from abundant first-row transition metals with competitive photophysical and photochemical properties have been elusive. While previous research efforts focused mostly on Fe(II), we disclose that isoelectronic Cr(0) gives access to higher photoluminescence quantum yields and excited-state lifetimes when compared with any other first-row d6 metal complex reported so far. The luminescence behaviour of the metal-to-ligand charge transfer excited states of these Cr(0) complexes is competitive with Os(II) polypyridines. With these Cr(0) complexes, the metal-to-ligand charge transfer states of first-row d6 metal complexes become exploitable in photoredox catalysis, and benchmark chemical reductions proceed efficiently under low-energy red illumination. Here we demonstrate that appropriate molecular design strategies open up new perspectives for photophysics and photochemistry with abundant first-row d6 metals.
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Affiliation(s)
- Narayan Sinha
- Department of Chemistry, University of Basel, Basel, Switzerland
| | | | | | | | - Oliver S Wenger
- Department of Chemistry, University of Basel, Basel, Switzerland.
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10
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Wang C, Wegeberg C, Wenger OS. First-Row d 6 Metal Complex Enables Photon Upconversion and Initiates Blue Light-Dependent Polymerization with Red Light. Angew Chem Int Ed Engl 2023; 62:e202311470. [PMID: 37681516 DOI: 10.1002/anie.202311470] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/07/2023] [Accepted: 09/08/2023] [Indexed: 09/09/2023]
Abstract
Photosensitizers for sensitized triplet-triplet annihilation upconversion (sTTA-UC) often rely on precious heavy metals, whereas coordination complexes based on abundant first-row transition metals are less common. This is mainly because long-lived triplet excited states are more difficult to obtain for 3d metals, particularly when the d-subshell is only partially filled. Here, we report the first example of sTTA-UC based on a 3d6 metal photosensitizer yielding an upconversion performance competitive with precious metal-based analogues. Using a newly developed Cr0 photosensitizer featuring equally good photophysical properties as an OsII benchmark complex in combination with an acetylene-decorated anthracene annihilator, red-to-blue upconversion is achievable. The upconversion efficiency under optimized conditions is 1.8 %, and the excitation power density threshold to reach the strong annihilation limit is 5.9 W/cm2 . These performance factors, along with high photostability, permit the initiation of acrylamide polymerization by red light, based on radiative energy transfer between delayed annihilator fluorescence and a blue light absorbing photo-initiator. Our study provides the proof-of-concept for photon upconversion with elusive first-row analogues of widely employed precious d6 metal photosensitizers, and for their application in photochemical reactions triggered by excitation wavelengths close to near-infrared.
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Affiliation(s)
- Cui Wang
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
- Current address: Department of Biology and Chemistry, Osnabrück University, Barbarastraße 7, 49076, Osnabrück, Germany
| | - Christina Wegeberg
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
- Current address: Division of Chemical Physics, Department of Chemistry, Lund University Box 124, 22100, Lund, Sweden
| | - Oliver S Wenger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
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11
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Bens T, Marhöfer D, Boden P, Steiger ST, Suntrup L, Niedner-Schatteburg G, Sarkar B. A Different Perspective on Tuning the Photophysical and Photochemical Properties: The Influence of Constitutional Isomers in Group 6 Carbonyl Complexes with Pyridyl-Mesoionic Carbenes. Inorg Chem 2023; 62:16182-16195. [PMID: 37721537 DOI: 10.1021/acs.inorgchem.3c02478] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
Exploring novel and existing design principles to tune the photochemical and photophysical properties of transition-metal complexes is an important goal in contemporary research. Here, we highlight the influence of constitutional isomers of pyridyl-1,2,3-triazolylidene mesoionic carbene (MIC) ligands on the photophysical and photochemical properties of the corresponding tetracarbonyl group 6 metal complexes (M = Cr, Mo, W). All new complexes [M(C-C)] presented herein incorporate a C-C linked pyridyl-MIC ligand and were fully characterized by X-ray diffraction analysis, elemental analysis, and 1H NMR and IR spectroscopy. Detailed photophysical investigations reveal a single emission in the VIS region, which extends into the NIR with lifetimes of up to 3.5 μs in the solid state at lower temperatures. The quantum yields were determined for all three complexes, and, in particular, the W0 complex shows an unusually high quantum yield of 29% compared to the values of 0.02% obtained for the [M(C-N)] isomers investigated in earlier works. Beyond this, the investigated W0 complex also exhibits an emission at 717 nm in a fluid solution. The combination of luminescence and FTIR-step scan spectroscopy with theoretical calculations reveals an emissive 3MLCT state. Irradiation of the presented complexes leads to a clean cleavage of one axial CO ligand. A metastable 16 VE species with a vacant axial coordination site was detected in the solid state at low temperatures. In solution, the respective solvato complexes are formed. A dark reverse reaction is observed, as previously described for the [M(C-N)] analogues. The increased electron density induced by the C-C linked pyridyl-MIC ligand leads to an increased kinetic rate constant for the reformation of the starting species and is also reflected in the lower photodissociation quantum yields.
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Affiliation(s)
- Tobias Bens
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart D-70569, Germany
- Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraße 34-36, Berlin 14195, Germany
| | - Daniel Marhöfer
- Department of Chemistry and Research Center Optimas, TU Kaiserslautern, Erwin-Schrödinger-Straße, Kaiserslautern 67663, Germany
| | - Pit Boden
- Department of Chemistry and Research Center Optimas, TU Kaiserslautern, Erwin-Schrödinger-Straße, Kaiserslautern 67663, Germany
| | - Sophie T Steiger
- Department of Chemistry and Research Center Optimas, TU Kaiserslautern, Erwin-Schrödinger-Straße, Kaiserslautern 67663, Germany
| | - Lisa Suntrup
- Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraße 34-36, Berlin 14195, Germany
| | - Gereon Niedner-Schatteburg
- Department of Chemistry and Research Center Optimas, TU Kaiserslautern, Erwin-Schrödinger-Straße, Kaiserslautern 67663, Germany
| | - Biprajit Sarkar
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart D-70569, Germany
- Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraße 34-36, Berlin 14195, Germany
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12
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Connelly PT, Applegate JC, Maldonado DA, Okeowo MK, Henke WC, Oliver AG, Berrie CL, Barybin MV. Homoleptic complexes of isocyano- and diisocyanobiazulenes with a 12-electron, ligand-based redox capacity. Dalton Trans 2023; 52:11419-11426. [PMID: 37538026 PMCID: PMC10498685 DOI: 10.1039/d3dt01958f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
Oligo- and polyazulenes are attractive π-conjugated building blocks in designing advanced functional materials. Herein, we demonstrate that anchoring one or both isocyanide termini of the redox non-innocent 2,2'-diisocyano-6,6'-biazulenic π-linker (1) to the redox-active [Cr(CO)5] moiety provided a convenient intramolecular redox reference for unambiguously establishing that the 6,6'-biazulenic scaffold undergoes a reversible one-step 2e- reduction governed by reduction potential compression/inversion. Treatment of bis(η6-naphthalene)chromium(0) with six equiv. of 2-isocyano-1,1',3,3'-tetraethoxycarbonyl-6,6'-biazulene (6) or [(OC)5Cr(η1-2,2'-diisocyano-1,1',3,3'-tetraethoxycarbonyl-6,6'-biazulene)] (11) afforded homoleptic Cr(0) complexes 13 and 14 with a 12e- (per molecule) ligand-based reduction capacity at mild E1/2 of -1.29 V and -1.15 V vs. Cp2Fe0/+, respectively. The overall reversible redox capacity varies from 15e- for the mononuclear complex 13 to 21e- for the heptanuclear complex 14. The latter "nanocomplex" has a diameter of ca. 5 nm and features seven Cr(0) centers interlinked with six 2,2'-diisocyano-6,6'-biazulenic bridges. The X-ray structure of [(OC)5Cr(2-isocyano-1,1',3,3'-tetraethoxycarbonyl-6,6'-biazulene)] (7) indicated a 43.5° interplanar angle between the two azulenic moieties. Self-assembly of 11 on a Au(111) substrate afforded an organometallic monolayer film of 11 featuring approximately upright orientation of the 2,2'-diisocyano-6,6'-biazulenic linkers, as evidenced by ellipsometric measurements and the RAIR signature of the C4v-symmetric [(-NC)Cr(CO)5] infrared reporter within 11. Remarkably, comparing the FTIR spectrum of 11 in solution with the RAIR spectrum of 11 adsorbed on Au(111) suggested electronic coupling at a ca. 2 nm distance between the Cr(0) and Au atoms linked by the 2,2'-diisocyano-6,6'-biazulene bridge.
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Affiliation(s)
| | - Jason C Applegate
- Department of Chemistry, University of Kansas, Lawrence, KS 66045, USA.
| | - David A Maldonado
- Department of Chemistry, University of Kansas, Lawrence, KS 66045, USA.
| | - Monisola K Okeowo
- Department of Chemistry, University of Kansas, Lawrence, KS 66045, USA.
| | - Wade C Henke
- Department of Chemistry, University of Kansas, Lawrence, KS 66045, USA.
| | - Allen G Oliver
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Cindy L Berrie
- Department of Chemistry, University of Kansas, Lawrence, KS 66045, USA.
| | - Mikhail V Barybin
- Department of Chemistry, University of Kansas, Lawrence, KS 66045, USA.
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13
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Barth AT, Fajardo J, Sattler W, Winkler JR, Gray HB. Electronic Structures and Photoredox Chemistry of Tungsten(0) Arylisocyanides. Acc Chem Res 2023. [PMID: 37384787 DOI: 10.1021/acs.accounts.3c00184] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
ConspectusThe high energy barriers associated with the reaction chemistry of inert substrates can be overcome by employing redox-active photocatalysts. Research in this area has grown exponentially over the past decade, as transition metal photosensitizers have been shown to mediate challenging organic transformations. Critical for the advancement of photoredox catalysis is the discovery, development, and study of complexes based on earth-abundant metals that can replace and/or complement established noble-metal-based photosensitizers.Recent work has focused on redox-active complexes of 3d metals, as photosensitizers containing these metals most likely would be scalable. Although low lying spin doublet ("spin flip") excited states of chromium(III) and metal-to-ligand charge transfer (MLCT) excited states of copper(I) have relatively long lifetimes, the electronic excited states of many other 3d metal complexes fall on dissociative potential energy surfaces, owing to the population of highly energetic σ-antibonding orbitals. Indeed, we and other investigators have shown that low lying spin singlet and triplet excited states of robust closed-shell metal complexes are too short-lived at room temperature to engage in bimolecular reactions in solutions. In principle, this problem could be overcome by designing and constructing 3d metal complexes containing strong field π-acceptor ligands, where thermally equilibrated MLCT or intraligand charge transfer excited states might fall well below the upper surfaces of dissociative 3d-3d states. Notably, such design elements have been exploited by investigators in very recent work on redox-active iron(II) systems. Another approach, one we have actively pursued, is to design and construct closed-shell complexes of earth-abundant 5d metals containing very strong π-acceptor ligands, where vertical excitation of 5d-5d excited states at the ground state geometry would require energies far above minima in the potential surfaces of MLCT excited states. As this requirement is met by tungsten(0) arylisocyanides, these complexes have been the focus of our work aimed at the development of robust redox-active photosensitizers.In the following Account, we review recent work on homoleptic tungsten(0) arylisocyanides. Originally reported by our group 45 years ago, W(CNAr)6 complexes have exceptionally large one- and two-photon absorption cross-sections. One- or two-photon excitation produces relatively long-lived (hundreds of nanoseconds to microsecond) MLCT excited states in high yields. These MLCT excited states, which are very strong reductants with E°(W+/*W0) = -2.2 to -3.0 V vs Fc[+/0], mediate photocatalysis of organic reactions with both visible and near-infrared (NIR) light. Here, we highlight design principles that led to the development of three generations of W(CNAr)6 photosensitizers; and we discuss likely steps in the mechanism of a prototypal W(CNAr)6-catalyzed base-promoted homolytic aromatic substitution reaction. Among the many potential applications of these very bright luminophores, two-photon imaging and two-photon-initiated polymerization are ones we plan to pursue.
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Affiliation(s)
- Alexandra T Barth
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Javier Fajardo
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Wesley Sattler
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Jay R Winkler
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Harry B Gray
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States
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14
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Steube J, Kruse A, Bokareva OS, Reuter T, Demeshko S, Schoch R, Argüello Cordero MA, Krishna A, Hohloch S, Meyer F, Heinze K, Kühn O, Lochbrunner S, Bauer M. Janus-type emission from a cyclometalated iron(III) complex. Nat Chem 2023; 15:468-474. [PMID: 36849804 PMCID: PMC10070185 DOI: 10.1038/s41557-023-01137-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 01/19/2023] [Indexed: 03/01/2023]
Abstract
Although iron is a dream candidate to substitute noble metals in photoactive complexes, realization of emissive and photoactive iron compounds is demanding due to the fast deactivation of their charge-transfer states. Emissive iron compounds are scarce and dual emission has not been observed before. Here we report the FeIII complex [Fe(ImP)2][PF6] (HImP = 1,1'-(1,3-phenylene)bis(3-methyl-1-imidazol-2-ylidene)), showing a Janus-type dual emission from ligand-to-metal charge transfer (LMCT)- and metal-to-ligand charge transfer (MLCT)-dominated states. This behaviour is achieved by a ligand design that combines four N-heterocyclic carbenes with two cyclometalating aryl units. The low-lying π* levels of the cyclometalating units lead to energetically accessible MLCT states that cannot evolve into LMCT states. With a lifetime of 4.6 ns, the strongly reducing and oxidizing MLCT-dominated state can initiate electron transfer reactions, which could constitute a basis for future applications of iron in photoredox catalysis.
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Affiliation(s)
- Jakob Steube
- Institute of Inorganic Chemistry, Paderborn University, Paderborn, Germany
- Center for Sustainable Systems Design, Paderborn University, Paderborn, Germany
| | - Ayla Kruse
- Department of Life, Light and Matter, University of Rostock, Rostock, Germany
- Institute for Physics, University of Rostock, Rostock, Germany
| | - Olga S Bokareva
- Institute for Physics, University of Rostock, Rostock, Germany
- Institute of Physics, University of Kassel, Kassel, Germany
| | - Thomas Reuter
- Department of Chemistry, Johannes Gutenberg University, Mainz, Germany
| | - Serhiy Demeshko
- Institute of Inorganic Chemistry, University of Göttingen, Göttingen, Germany
| | - Roland Schoch
- Institute of Inorganic Chemistry, Paderborn University, Paderborn, Germany
- Center for Sustainable Systems Design, Paderborn University, Paderborn, Germany
| | - Miguel A Argüello Cordero
- Department of Life, Light and Matter, University of Rostock, Rostock, Germany
- Institute for Physics, University of Rostock, Rostock, Germany
| | - Athul Krishna
- Institute of Inorganic Chemistry, Paderborn University, Paderborn, Germany
- Center for Sustainable Systems Design, Paderborn University, Paderborn, Germany
| | - Stephan Hohloch
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Franc Meyer
- Institute of Inorganic Chemistry, University of Göttingen, Göttingen, Germany
| | - Katja Heinze
- Department of Chemistry, Johannes Gutenberg University, Mainz, Germany
| | - Oliver Kühn
- Department of Life, Light and Matter, University of Rostock, Rostock, Germany
- Institute for Physics, University of Rostock, Rostock, Germany
| | - Stefan Lochbrunner
- Department of Life, Light and Matter, University of Rostock, Rostock, Germany
- Institute for Physics, University of Rostock, Rostock, Germany
| | - Matthias Bauer
- Institute of Inorganic Chemistry, Paderborn University, Paderborn, Germany.
- Center for Sustainable Systems Design, Paderborn University, Paderborn, Germany.
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15
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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: 40] [Impact Index Per Article: 40.0] [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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16
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Li G, Jiang Z, Tang M, Jiang X, Tu H, Zhu S, Liu R, Zhu H. Synthesis, Photophysics and Tunable Reverse Saturable Absorption of Bis-Tridentate Iridium(III) Complexes via Modification on Diimine Ligand. Molecules 2023; 28:molecules28020566. [PMID: 36677626 PMCID: PMC9864372 DOI: 10.3390/molecules28020566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 12/25/2022] [Accepted: 01/02/2023] [Indexed: 01/09/2023] Open
Abstract
Five novel bis-tridentate Ir(III) complexes (Ir-1−Ir-5) incorporating versatile N^N^C ligands and a N^C^N ligand (1,3-di(2-pyridyl)-4,6-dimethylbenzene) were synthesized. With the combination of experimental and theoretical methods, their steady and transient state characteristics were researched scientifically. The UV-visible absorption spectra show that the broadband charge transfer absorbance of those bis-tridentate Ir(III) complexes can reach 550 nm, all of these complexes reveal the long-lasting phosphorescent emission. Because the excited-state absorption is more powerful than the ground-state absorption, a sturdy reverse saturable absorption (RSA) process can ensue in the visible and near-infrared regions when the complexes are exposed to a 532 nm laser. Therefore, the optical power limiting (OPL) effect follows the trend: Ir-5 > Ir-4 ≈ Ir-3 > Ir-2 > Ir-1. Generally speaking, the expansion of π-conjugation and the introduction of electron donating/withdrawing groups on the N^N^C ligand could effectively elevate the OPL effect. Therefore, these octahedral bis-tridentate Ir(III) complexes might be exploited as potential OPL materials.
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Affiliation(s)
| | | | | | | | | | | | - Rui Liu
- Correspondence: (S.Z.); (R.L.)
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17
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Glaser F, Wenger OS. Sensitizer-controlled photochemical reactivity via upconversion of red light. Chem Sci 2022; 14:149-161. [PMID: 36605743 PMCID: PMC9769107 DOI: 10.1039/d2sc05229f] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 11/21/2022] [Indexed: 12/02/2022] Open
Abstract
By combining the energy input from two red photons, chemical reactions that would normally require blue or ultraviolet irradiation become accessible. Key advantages of this biphotonic excitation strategy are that red light usually penetrates deeper into complex reaction mixtures and causes less photo-damage than direct illumination in the blue or ultraviolet. Here, we demonstrate that the primary light-absorber of a dual photocatalytic system comprised of a transition metal-based photosensitizer and an organic co-catalyst can completely alter the reaction outcome. Photochemical reductions are achieved with a copper(i) complex in the presence of a sacrificial electron donor, whereas oxidative substrate activation occurs with an osmium(ii) photosensitizer. Based on time-resolved laser spectroscopy, this changeover in photochemical reactivity is due to different underlying biphotonic mechanisms. Following triplet energy transfer from the osmium(ii) photosensitizer to 9,10-dicyanoanthracene (DCA) and subsequent triplet-triplet annihilation upconversion, the fluorescent singlet excited state of DCA triggers oxidative substrate activation, which initiates the cis to trans isomerization of an olefin, a [2 + 2] cycloaddition, an aryl ether to ester rearrangement, and a Newman-Kwart rearrangement. This oxidative substrate activation stands in contrast to the reactivity with a copper(i) photosensitizer, where photoinduced electron transfer generates the DCA radical anion, which upon further excitation triggers reductive dehalogenations and detosylations. Our study provides the proof-of-concept for controlling the outcome of a red-light driven biphotonic reaction by altering the photosensitizer, and this seems relevant in the greater context of tailoring photochemical reactivities.
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Affiliation(s)
- Felix Glaser
- 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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18
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Ogawa T, Sinha N, Pfund B, Prescimone A, Wenger OS. Molecular Design Principles to Elongate the Metal-to-Ligand Charge Transfer Excited-State Lifetimes of Square-Planar Nickel(II) Complexes. J Am Chem Soc 2022; 144:21948-21960. [DOI: 10.1021/jacs.2c08838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Tomohiro Ogawa
- 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
| | - Björn Pfund
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Alessandro Prescimone
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Oliver S. Wenger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
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19
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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. [PMID: 36279568 PMCID: PMC9644379 DOI: 10.1021/acs.inorgchem.2c02410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Indexed: 11/30/2022]
Abstract
Fe(III) complexes with N-heterocyclic carbene (NHC) ligands belong to the rare examples of Earth-abundant transition metal complexes with long-lived luminescent charge-transfer excited states that enable applications as photosensitizers for charge separation reactions. We report three new hexa-NHC complexes of this class: [Fe(brphtmeimb)2]PF6 (brphtmeimb = [(4-bromophenyl)tris(3-methylimidazol-2-ylidene)borate]-, [Fe(meophtmeimb)2]PF6 (meophtmeimb = [(4-methoxyphenyl)tris(3-methylimidazol-2-ylidene)borate]-, and [Fe(coohphtmeimb)2]PF6 (coohphtmeimb = [(4-carboxyphenyl)tris(3-methylimidazol-2-ylidene)borate]-. These were derived from the parent complex [Fe(phtmeimb)2]PF6 (phtmeimb = [phenyltris(3-methylimidazol-2-ylidene)borate]- by modification with electron-withdrawing and electron-donating substituents, respectively, at the 4-phenyl position of the ligand framework. All three Fe(III) hexa-NHC complexes were characterized by NMR spectroscopy, high-resolution mass spectroscopy, elemental analysis, single crystal X-ray diffraction analysis, electrochemistry, Mößbauer spectroscopy, electronic spectroscopy, magnetic susceptibility measurements, and quantum chemical calculations. Their ligand-to-metal charge-transfer (2LMCT) excited states feature nanosecond lifetimes (1.6-1.7 ns) and sizable emission quantum yields (1.7-1.9%) through spin-allowed transition to the doublet ground state (2GS), completely in line with the parent complex [Fe(phtmeimb)2]PF6 (2.0 ns and 2.1%). The integrity of the favorable excited state characteristics upon substitution of the ligand framework demonstrates the robustness of the scorpionate motif that tolerates modifications in the 4-phenyl position for applications such as the attachment in molecular or hybrid assemblies.
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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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20
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Muthig AMT, Krumrein M, Wieland J, Gernert M, Kerner F, Pflaum J, Steffen A. Trigonal Copper(I) Complexes with Cyclic (Alkyl)(amino)carbene Ligands for Single-Photon Near-IR Triplet Emission. Inorg Chem 2022; 61:14833-14844. [PMID: 36069727 DOI: 10.1021/acs.inorgchem.2c02376] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular near-IR (NIR) triplet-state emitters are of importance for the development of new, organic-electronics-based telecommunication technologies as optical fibers operating in the corresponding spectral bands allow for data transfer over much longer distances due to the significantly lower attenuation. However, achieving such low-energy triplet excited states with good radiative rate constants is very challenging, and studies regarding the single-photon emission of organometallics in this energy range are scarce. We have prepared a series of trigonal CuI CAAC complexes bearing chelating ligands with O, N, S, and Se donor atoms and studied their photophysical properties in this context. The compounds show weak low-energy absorption in solution between 400 and 500 nm due to mixed Cu → CAAC 1MLCT/LLCT states, resulting in yellow-green to orange appearance, which we have also correlated to the 15N NMR resonances of the π-accepting carbene ligand. In the solid state, phosphorescence from dominant 3(Cu → CAAC) CT states is observed at room temperature. The emission of the complexes is bathochromically shifted in comparison to structurally related linearly coordinated copper(I) CAAC complexes due to structural reorganization in the excited state to a T-shape. For [Cu(dbm)(CAACMe)], the broad phosphorescence with outstanding λmax = 760 nm tailors out to ca. 1100 nm and leads to its proof-of-concept application as a nonclassical single-photon light source, constituting key functional units for the implementation of tap-proof data transfer.
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Affiliation(s)
- André M T Muthig
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Marcel Krumrein
- Experimental Physics, Experimental Physics VI, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Justin Wieland
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Markus Gernert
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Florian Kerner
- Institute of Inorganic Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Jens Pflaum
- Experimental Physics, Experimental Physics VI, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Andreas Steffen
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
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21
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Schwehr BJ, Hartnell D, Massi M, Hackett MJ. Luminescent Metal Complexes as Emerging Tools for Lipid Imaging. Top Curr Chem (Cham) 2022; 380:46. [PMID: 35976575 PMCID: PMC9385838 DOI: 10.1007/s41061-022-00400-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 06/20/2022] [Indexed: 12/01/2022]
Abstract
Fluorescence microscopy is a key tool in the biological sciences, which finds use as a routine laboratory technique (e.g., epifluorescence microscope) or more advanced confocal, two-photon, and super-resolution applications. Through continued developments in microscopy, and other analytical methods, the importance of lipids as constituents of subcellular organelles, signalling or regulating molecules continues to emerge. The increasing recognition of the importance of lipids to fundamental cell biology (in health and disease) has prompted the development of protocols and techniques to image the distribution of lipids in cells and tissues. A diverse suite of spectroscopic and microscopy tools are continuously being developed and explored to add to the "toolbox" to study lipid biology. A relatively recent breakthrough in this field has been the development and subsequent application of metal-based luminescent complexes for imaging lipids in biological systems. These metal-based compounds appear to offer advantages with respect to their tunability of the photophysical properties, in addition to capabilities centred around selectively targeting specific lipid structures or classes of lipids. The presence of the metal centre also opens the path to alternative imaging modalities that might not be applicable to traditional organic fluorophores. This review examines the current progress and developments in metal-based luminescent complexes to study lipids, in addition to exploring potential new avenues and challenges for the field to take.
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Affiliation(s)
- Bradley J Schwehr
- School of Molecular and Life Sciences, Curtin University, Perth, WA, 6845, Australia
| | - David Hartnell
- School of Molecular and Life Sciences, Curtin University, Perth, WA, 6845, Australia.,Curtin Health Innovation Research Institute, Curtin University, Perth, WA, 6845, Australia
| | - Massimiliano Massi
- School of Molecular and Life Sciences, Curtin University, Perth, WA, 6845, Australia.
| | - Mark J Hackett
- School of Molecular and Life Sciences, Curtin University, Perth, WA, 6845, Australia. .,Curtin Health Innovation Research Institute, Curtin University, Perth, WA, 6845, Australia.
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22
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Lee LCC, Lo KKW. Luminescent and Photofunctional Transition Metal Complexes: From Molecular Design to Diagnostic and Therapeutic Applications. J Am Chem Soc 2022; 144:14420-14440. [PMID: 35925792 DOI: 10.1021/jacs.2c03437] [Citation(s) in RCA: 66] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
There has been emerging interest in the exploitation of the photophysical and photochemical properties of transition metal complexes for diagnostic and therapeutic applications. In this Perspective, we highlight the major recent advances in the development of luminescent and photofunctional transition metal complexes, in particular, those of rhenium(I), ruthenium(II), osmium(II), iridium(III), and platinum(II), as bioimaging reagents and phototherapeutic agents, with a focus on the molecular design strategies that harness and modulate the interesting photophysical and photochemical behavior of the complexes. We also discuss the current challenges and future outlook of transition metal complexes for both fundamental research and clinical applications.
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Affiliation(s)
- Lawrence Cho-Cheung Lee
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P.R. China.,Laboratory for Synthetic Chemistry and Chemical Biology Limited, Units 1503-1511, 15/F, Building 17W, Hong Kong Science Park, New Territories, Hong Kong, P.R. China
| | - Kenneth Kam-Wing Lo
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P.R. China.,State Key Laboratory of Terahertz and Millimeter Waves, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P.R. China
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23
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Cadranel A, Gravogl L, Munz D, Meyer K. Intense Photoinduced Intervalence Charge Transfer in High-Valent Iron Mixed Phenolate/Carbene Complexes. Chemistry 2022; 28:e202200269. [PMID: 35302682 PMCID: PMC9401866 DOI: 10.1002/chem.202200269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Indexed: 11/09/2022]
Abstract
We report high-valent iron complexes supported by N-heterocyclic carbene (NHC)-anchored, bis-phenolate pincer ligands that undergo ligand-to-metal charge transfer (LMCT) upon photoexcitation. The resulting excited states - with a lifetime in the picosecond range - feature a ligand-based, mixed-valence system and intense intervalence charge transfer bands in the near-infrared region. Upon oxidation of the complex, corresponding intervalence charge transfer absorptions are also observed in the ground state. We suggest that the spectroscopic hallmarks of such LMCT states provide useful tools to decipher excited-state decay mechanisms in high-valent NHC complexes. Our observations further indicate that NHC-anchored, bis-phenolate pincer ligands are not sufficiently strong donors to prevent the population of excited metal-centered states in high-valent iron complexes.
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Affiliation(s)
- Alejandro Cadranel
- Department Chemie und PharmaziePhysikalische ChemieFriedrich-Alexander-Universität Erlangen–NürnbergEgerlandstraße 391058ErlangenGermany
- Departamento de Química InorgánicaAnalítica y Química FísicaUniversidad de Buenos AiresFacultad de Ciencias Exactas y NaturalesPabellón 2, Ciudad UniversitariaC1428EHABuenos AiresArgentina
- Instituto de Química Física de MaterialesMedio Ambiente y Energía (INQUIMAE)CONICET–Universidad de Buenos AiresPabellón 2, Ciudad UniversitariaC1428EHABuenos AiresArgentina
| | - Lisa Gravogl
- Department Chemie und PharmazieAnorganische ChemieFriedrich-Alexander-Universität Erlangen–NürnbergEgerlandstraße 191058ErlangenGermany
| | - Dominik Munz
- Department Chemie und PharmazieAnorganische ChemieFriedrich-Alexander-Universität Erlangen–NürnbergEgerlandstraße 191058ErlangenGermany
- Anorganische Chemie: KoordinationschemieUniversität des SaarlandesCampus C4.166123SaarbrückenGermany
| | - Karsten Meyer
- Department Chemie und PharmazieAnorganische ChemieFriedrich-Alexander-Universität Erlangen–NürnbergEgerlandstraße 191058ErlangenGermany
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24
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Ossinger S, Prescimone A, Häussinger D, Wenger OS. Manganese(I) Complex with Monodentate Arylisocyanide Ligands Shows Photodissociation Instead of Luminescence. Inorg Chem 2022; 61:10533-10547. [PMID: 35768069 PMCID: PMC9377510 DOI: 10.1021/acs.inorgchem.2c01438] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recently reported manganese(I) complexes with chelating arylisocyanide ligands exhibit luminescent metal-to-ligand charge-transfer (MLCT) excited states, similar to ruthenium(II) polypyridine complexes with the same d6 valence electron configuration used for many different applications in photophysics and photochemistry. However, chelating arylisocyanide ligands require substantial synthetic effort, and therefore it seemed attractive to explore the possibility of using more readily accessible monodentate arylisocyanides instead. Here, we synthesized the new Mn(I) complex [Mn(CNdippPhOMe2)6]PF6 with the known ligand CNdippPhOMe2 = 4-(3,5-dimethoxyphenyl)-2,6-diisopropylphenylisocyanide. This complex was investigated by NMR spectroscopy, single-crystal structure analysis, high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) measurements, IR spectroscopy supported by density functional theory (DFT) calculations, cyclic voltammetry, and time-resolved as well as steady-state UV-vis absorption spectroscopy. The key finding is that the new Mn(I) complex is nonluminescent and instead undergoes arylisocyanide ligand loss during continuous visible laser irradiation into ligand-centered and charge-transfer absorption bands, presumably owed to the population of dissociative d-d excited states. Thus, it seems that chelating bi- or tridentate binding motifs are essential for obtaining emissive MLCT excited states in manganese(I) arylisocyanides. Our work contributes to understanding the basic properties of photoactive first-row transition metal complexes and could help advance the search for alternatives to precious metal-based luminophores, photocatalysts, and sensors.
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Affiliation(s)
- Sascha Ossinger
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Alessandro Prescimone
- Department
of Chemistry, University of Basel, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Daniel Häussinger
- 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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25
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Wang C, Reichenauer F, Kitzmann WR, Kerzig C, Heinze K, Resch‐Genger U. Efficient Triplet-Triplet Annihilation Upconversion Sensitized by a Chromium(III) Complex via an Underexplored Energy Transfer Mechanism. Angew Chem Int Ed Engl 2022; 61:e202202238. [PMID: 35344256 PMCID: PMC9322448 DOI: 10.1002/anie.202202238] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Indexed: 12/14/2022]
Abstract
Sensitized triplet-triplet annihilation upconversion (sTTA-UC) mainly relies on precious metal complexes thanks to their high intersystem crossing (ISC) efficiencies, excited state energies, and lifetimes, while complexes of abundant first-row transition metals are only rarely utilized and with often moderate UC quantum yields. [Cr(bpmp)2 ]3+ (bpmp=2,6-bis(2-pyridylmethyl)pyridine) containing earth-abundant chromium possesses an absorption band suitable for green light excitation, a doublet excited state energy matching the triplet energy of 9,10-diphenyl anthracene (DPA), a close to millisecond excited state lifetime, and high photostability. Combined ISC and doublet-triplet energy transfer from excited [Cr(bpmp)2 ]3+ to DPA gives 3 DPA with close-to-unity quantum yield. TTA of 3 DPA furnishes green-to-blue UC with a quantum yield of 12.0 % (close to the theoretical maximum). Sterically less-hindered anthracenes undergo a [4+4] cycloaddition with [Cr(bpmp)2 ]3+ and green light.
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Affiliation(s)
- Cui Wang
- Division BiophotonicsFederal Institute for Materials Research and Testing (BAM)Richard-Willstätter-Strasse 1112489BerlinGermany
- Institute of Chemistry and BiochemistryFree University of BerlinArnimallee 2214195BerlinGermany
| | - Florian Reichenauer
- Department of ChemistryJohannes Gutenberg University of MainzDuesbergweg 10–1455128MainzGermany
| | - Winald R. Kitzmann
- Department of ChemistryJohannes Gutenberg University of MainzDuesbergweg 10–1455128MainzGermany
| | - Christoph Kerzig
- Department of ChemistryJohannes Gutenberg University of MainzDuesbergweg 10–1455128MainzGermany
| | - Katja Heinze
- Department of ChemistryJohannes Gutenberg University of MainzDuesbergweg 10–1455128MainzGermany
| | - Ute Resch‐Genger
- Division BiophotonicsFederal Institute for Materials Research and Testing (BAM)Richard-Willstätter-Strasse 1112489BerlinGermany
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26
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Sinha N, Pfund B, Wegeberg C, Prescimone A, Wenger OS. Cobalt(III) Carbene Complex with an Electronic Excited-State Structure Similar to Cyclometalated Iridium(III) Compounds. J Am Chem Soc 2022; 144:9859-9873. [PMID: 35623627 PMCID: PMC9490849 DOI: 10.1021/jacs.2c02592] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Many organometallic
iridium(III) complexes have photoactive excited
states with mixed metal-to-ligand and intraligand charge transfer
(MLCT/ILCT) character, which form the basis for numerous applications
in photophysics and photochemistry. Cobalt(III) complexes with analogous
MLCT excited-state properties seem to be unknown yet, despite the
fact that iridium(III) and cobalt(III) can adopt identical low-spin
d6 valence electron configurations due to their close chemical
relationship. Using a rigid tridentate chelate ligand (LCNC), in which a central amido π-donor is flanked by two σ-donating
N-heterocyclic carbene subunits, we obtained a robust homoleptic complex
[Co(LCNC)2](PF6), featuring a photoactive
excited state with substantial MLCT character. Compared to the vast
majority of isoelectronic iron(II) complexes, the MLCT state of [Co(LCNC)2](PF6) is long-lived because it
does not deactivate as efficiently into lower-lying metal-centered
excited states; furthermore, it engages directly in photoinduced electron
transfer reactions. The comparison with [Fe(LCNC)2](PF6), as well as structural, electrochemical, and UV–vis
transient absorption studies, provides insight into new ligand design
principles for first-row transition-metal complexes with photophysical
and photochemical properties reminiscent of those known from the platinum
group metals.
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Affiliation(s)
- Narayan Sinha
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Björn Pfund
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Christina Wegeberg
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Alessandro Prescimone
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Oliver S Wenger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
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27
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Wang C, Reichenauer F, Kitzmann WR, Kerzig C, Heinze K, Resch‐Genger U. Efficient Triplet‐Triplet Annihilation Upconversion Sensitized by a Chromium(III) Complex via an Underexplored Energy Transfer Mechanism. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Cui Wang
- Division Biophotonics Federal Institute for Materials Research and Testing (BAM) Richard-Willstätter-Strasse 11 12489 Berlin Germany
- Institute of Chemistry and Biochemistry Free University of Berlin Arnimallee 22 14195 Berlin Germany
| | - Florian Reichenauer
- Department of Chemistry Johannes Gutenberg University of Mainz Duesbergweg 10–14 55128 Mainz Germany
| | - Winald R. Kitzmann
- Department of Chemistry Johannes Gutenberg University of Mainz Duesbergweg 10–14 55128 Mainz Germany
| | - Christoph Kerzig
- 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
| | - Ute Resch‐Genger
- Division Biophotonics Federal Institute for Materials Research and Testing (BAM) Richard-Willstätter-Strasse 11 12489 Berlin Germany
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28
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Barth AT, Morales M, Winkler JR, Gray HB. Photoredox Catalysis Mediated by Tungsten(0) Arylisocyanides in 1,2-Difluorobenzene. Inorg Chem 2022; 61:7251-7255. [PMID: 35486113 DOI: 10.1021/acs.inorgchem.1c03767] [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
We have studied the photochemical cyclization of 1-(2-iodobenzyl)-pyrrole (IBP) and 1-(2-bromobenzyl)-pyrrole (BBP) to 5H-pyrrolo[2,1-a]isoindol catalyzed by W(CNDipp)6 (CNDipp = 2,6-diisopropylphenylisocyanide) in 1,2-difluorobenzene (DFB). Irradiation (445 nm) of W(CNDipp)6 (5 mol %) in DFB solution converted 78% of IBP (50 mM) to product after 1 h (16 turnovers). Addition of tetra-n-butyl ammonium hexafluorophosphate (TBAPF6) (0.2 M) to the DFB solution led to rapid photoinduced disappearance of W(CNDipp)6 but, remarkably, did not inhibit photochemical cyclization of IBP, indicating that IBP cyclization could be driven by a nonluminescent photocatalyst.
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Affiliation(s)
- Alexandra T Barth
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Maryann Morales
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Jay R Winkler
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Harry B Gray
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States
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29
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Herr P, Schwab A, Kupfer S, Wenger OS. Deep‐Red Luminescent Molybdenum(0) Complexes with Bi‐ and Tridentate Isocyanide Chelate Ligands. CHEMPHOTOCHEM 2022. [DOI: 10.1002/cptc.202200052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Patrick Herr
- University of Basel: Universitat Basel Department of Chemistry SWITZERLAND
| | - Alexander Schwab
- Friedrich-Schiller-Universität Jena: Friedrich-Schiller-Universitat Jena Institute of Physical Chemistry GERMANY
| | - Stephan Kupfer
- Friedrich-Schiller-Universität Jena: Friedrich-Schiller-Universitat Jena Institute of Physical Chemistry GERMANY
| | - Oliver S. Wenger
- Universität Basel Departement für Chemie St. Johanns-Ring 19 4056 Basel SWITZERLAND
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30
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Ferraro V, Baggio F, Castro J, Bortoluzzi M. Green phosphorescent Zn(II) halide complexes with N,N,N',N'‐tetramethyl‐P‐indol‐1‐ylphosphonic diamide as ligand. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202200119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Valentina Ferraro
- Università Ca' Foscari Dipartimento di Scienze Molecolari e Nanosistemi Via Torino 155 30172 Venezia ITALY
| | - Filippo Baggio
- Università Ca' Foscari: Universita Ca' Foscari Dipartimento di Scienze Molecolari e Nanosistemi ITALY
| | - Jesús Castro
- Universidade de Vigo Departamento de Química Inorgánica 36310 Vigo SPAIN
| | - Marco Bortoluzzi
- CIRCC Consorzio Interuniversitario Reattività Chimica e Catalisi Via Celso Ulpiani 27 70126 Bari ITALY
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31
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Stein L, Boden P, Naumann R, Förster C, Niedner-Schatteburg G, Heinze K. The overlooked NIR luminescence of Cr(ppy) 3. Chem Commun (Camb) 2022; 58:3701-3704. [PMID: 35226026 DOI: 10.1039/d2cc00680d] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cr(ppy)3, a structural analog of the green phosphorescent Ir(ppy)3, emits even in solution at room temperature from a weakly distorted spin-flip state at 910 nm (Hppy = 2-phenylpyridine). The low energy arises from an enhanced covalence of the Cr-C bonds as compared to Cr-N bonds. Lower temperature reduces thermally activated decay increasing the emission intensity.
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Affiliation(s)
- Laura Stein
- Johannes Gutenberg-University, Department of Chemistry, Duesbergweg 10-14, Mainz, Germany.
| | - Pit Boden
- Department of Chemistry and Research Center Optimas, TU Kaiserslautern, Erwin-Schrödinger-Straße 52, 67663 Kaiserslautern, Germany
| | - Robert Naumann
- Johannes Gutenberg-University, Department of Chemistry, Duesbergweg 10-14, Mainz, Germany.
| | - Christoph Förster
- Johannes Gutenberg-University, Department of Chemistry, Duesbergweg 10-14, Mainz, Germany.
| | - Gereon Niedner-Schatteburg
- Department of Chemistry and Research Center Optimas, TU Kaiserslautern, Erwin-Schrödinger-Straße 52, 67663 Kaiserslautern, Germany
| | - Katja Heinze
- Johannes Gutenberg-University, Department of Chemistry, Duesbergweg 10-14, Mainz, Germany.
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32
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Wang C, Kitzmann WR, Weigert F, Förster C, Wang X, Heinze K, Resch-Genger U. Matrix Effects on Photoluminescence and Oxygen Sensitivity of a Molecular Ruby. CHEMPHOTOCHEM 2022. [DOI: 10.1002/cptc.202100296] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Cui Wang
- BAM Federal Institute for Materials Research and Testing: Bundesanstalt fur Materialforschung und -prufung Division Biophotonics Richard-Willstaetter-Str. 11 12489 Berlin GERMANY
| | - Winald R. Kitzmann
- Johannes Gutenberg University: Johannes Gutenberg Universitat Mainz Department of Chemistry GERMANY
| | - Florian Weigert
- BAM Federal Institute for Materials Research and Testing: Bundesanstalt fur Materialforschung und -prufung Division Biophotonics GERMANY
| | - Christoph Förster
- Johannes Gutenberg University: Johannes Gutenberg Universitat Mainz Department of Chemistry GERMANY
| | - Xifan Wang
- BAM Federal Institute for Materials Research and Testing: Bundesanstalt fur Materialforschung und -prufung Division Biophotonics GERMANY
| | - Katja Heinze
- Johannes Gutenberg University: Johannes Gutenberg Universitat Mainz Department of Chemistry GERMANY
| | - Ute Resch-Genger
- Bundesanstalt für Materialforschung und -prüfung (BAM) Analytische Chemie und Referenzmaterialien Richard-Willstaetter-Str. 11 12489 Berlin GERMANY
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33
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Housecroft CE, Constable EC. Solar energy conversion using first row d-block metal coordination compound sensitizers and redox mediators. Chem Sci 2022; 13:1225-1262. [PMID: 35222908 PMCID: PMC8809415 DOI: 10.1039/d1sc06828h] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 01/05/2022] [Indexed: 12/11/2022] Open
Abstract
The use of renewable energy is essential for the future of the Earth, and solar photons are the ultimate source of energy to satisfy the ever-increasing global energy demands. Photoconversion using dye-sensitized solar cells (DSCs) is becoming an established technology to contribute to the sustainable energy market, and among state-of-the art DSCs are those which rely on ruthenium(ii) sensitizers and the triiodide/iodide (I3 -/I-) redox mediator. Ruthenium is a critical raw material, and in this review, we focus on the use of coordination complexes of the more abundant first row d-block metals, in particular copper, iron and zinc, as dyes in DSCs. A major challenge in these DSCs is an enhancement of their photoconversion efficiencies (PCEs) which currently lag significantly behind those containing ruthenium-based dyes. The redox mediator in a DSC is responsible for regenerating the ground state of the dye. Although the I3 -/I- couple has become an established redox shuttle, it has disadvantages: its redox potential limits the values of the open-circuit voltage (V OC) in the DSC and its use creates a corrosive chemical environment within the DSC which impacts upon the long-term stability of the cells. First row d-block metal coordination compounds, especially those containing cobalt, and copper, have come to the fore in the development of alternative redox mediators and we detail the progress in this field over the last decade, with particular attention to Cu2+/Cu+ redox mediators which, when coupled with appropriate dyes, have achieved V OC values in excess of 1000 mV. We also draw attention to aspects of the recyclability of DSCs.
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Affiliation(s)
- Catherine E Housecroft
- Department of Chemistry, University of Basel Mattenstrasse 24a, BPR 1096 4058 Basel Switzerland
| | - Edwin C Constable
- Department of Chemistry, University of Basel Mattenstrasse 24a, BPR 1096 4058 Basel Switzerland
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34
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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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35
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Leis W, Argüello Cordero MA, Lochbrunner S, Schubert H, Berkefeld A. A Photoreactive Iron(II) Complex Luminophore. J Am Chem Soc 2022; 144:1169-1173. [PMID: 35025493 DOI: 10.1021/jacs.1c13083] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Controlling the order and lifetimes of electronically excited states is essential to effective light-to-potential energy conversion by molecular chromophores. This work reports a luminescent and photoreactive iron(II) complex, the first performant group homologue of prototypical sensitizers of ruthenium. Double cyclometalation of a phenylphenanthroline framework at iron(II) favors the population of a triplet metal-to-ligand charge transfer (3MLCT) state as the lowest energy excited state. Near-infrared (NIR) luminescence exhibits a monoexponential decay with τ = 2.4 ns in the solid state and 1 ns in liquid phase. Lifetimes of 14 ns at 77 K are in line with a narrowing of the NIR emission band at λem,max = 1170-1230 nm. Featuring a 3MLCT excited-state redox potential of -2 V vs the ferrocene/ferrocenium couple, the use of the Fe(II) chromophore as a sensitizer for light-driven synthesis is exemplified by the radical cross-coupling of 4-chlorobromobenzene and benzene.
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Affiliation(s)
- Wolfgang Leis
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, 72076 Tübingen, Germany
| | - Miguel A Argüello Cordero
- Institute for Physics and Department of Life, Light and Matter, University of Rostock, 18051 Rostock, Germany
| | - Stefan Lochbrunner
- Institute for Physics and Department of Life, Light and Matter, University of Rostock, 18051 Rostock, Germany
| | - Hartmut Schubert
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, 72076 Tübingen, Germany
| | - Andreas Berkefeld
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, 72076 Tübingen, Germany
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36
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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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37
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Larsen CB, Braun JD, Lozada IB, Kunnus K, Biasin E, Kolodziej C, Burda C, Cordones AA, Gaffney KJ, Herbert DE. Reduction of Electron Repulsion in Highly Covalent Fe-Amido Complexes Counteracts the Impact of a Weak Ligand Field on Excited-State Ordering. J Am Chem Soc 2021; 143:20645-20656. [PMID: 34851636 DOI: 10.1021/jacs.1c06429] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The ability to access panchromatic absorption and long-lived charge-transfer (CT) excited states is critical to the pursuit of abundant-metal molecular photosensitizers. Fe(II) complexes supported by benzannulated diarylamido ligands have been reported to broadly absorb visible light with nanosecond CT excited state lifetimes, but as amido donors exert a weak ligand field, this defies conventional photosensitizer design principles. Here, we report an aerobically stable Fe(II) complex of a phenanthridine/quinoline diarylamido ligand, Fe(ClL)2, with panchromatic absorption and a 3 ns excited-state lifetime. Using X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS) at the Fe L-edge and N K-edge, we experimentally validate the strong Fe-Namido orbital mixing in Fe(ClL)2 responsible for the panchromatic absorption and demonstrate a previously unreported competition between ligand-field strength and metal-ligand (Fe-Namido) covalency that stabilizes the 3CT state over the lowest energy triplet metal-centered (3MC) state in the ground-state geometry. Single-crystal X-ray diffraction (XRD) and density functional theory (DFT) suggest that formation of this CT state depopulates an orbital with Fe-Namido antibonding character, causing metal-ligand bonds to contract and accentuating the geometric differences between CT and MC excited states. These effects diminish the driving force for electron transfer to metal-centered excited states and increase the intramolecular reorganization energy, critical properties for extending the lifetime of CT excited states. These findings highlight metal-ligand covalency as a novel design principle for elongating excited state lifetimes in abundant metal photosensitizers.
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Affiliation(s)
- Christopher B Larsen
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Jason D Braun
- Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, MB R3T 2N2, Canada
| | - Issiah B Lozada
- Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, MB R3T 2N2, Canada
| | - Kristjan Kunnus
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Elisa Biasin
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Charles Kolodziej
- Department of Chemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Clemens Burda
- Department of Chemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Amy A Cordones
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Kelly J Gaffney
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - David E Herbert
- Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, MB R3T 2N2, Canada
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38
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Abstract
In this Frontier article, recently discovered chromium(0) and manganese(i) complexes emitting from metal-to-ligand charge transfer (MLCT) excited states are highlighted. Chelating isocyanide ligands give access to this new class of 3d6 emitters with MLCT lifetimes in (or close to) the nanosecond regime in solution at room temperature. Although the so far achievable luminescence quantum yields in these open-shell complexes are yet comparatively low, the photophysical properties of the new chromium(0) and manganese(i) isocyanides are reminiscent of those of well-known ruthenium(ii) polypyridines. Our findings provide insight into how undesired nonradiative MLCT deactivation in 3d6 complexes can be counteracted, and they seem therefore relevant for the further development of new luminescent first-row transition metal complexes based on iron(ii) and cobalt(iii) in addition to chromium(0) and manganese(i). In this Frontier article, recently discovered chromium(0) and manganese(i) complexes emitting from metal-to-ligand charge transfer (MLCT) excited states are highlighted.![]()
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Affiliation(s)
- Christina Wegeberg
- 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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Sutton GD, Olumba ME, Nguyen YH, Teets TS. The diverse functions of isocyanides in phosphorescent metal complexes. Dalton Trans 2021; 50:17851-17863. [PMID: 34787613 DOI: 10.1039/d1dt03312c] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In this Perspective, we highlight many examples of photoluminescent metal complexes supported by isocyanides, with an emphasis on recent developments including several from our own group. Work in this field has shown that the isocyanide can play important structural roles, both as a terminal ligand and as a bridging ligand for polynuclear structures, and can influence the excited-state character and excited-state dynamics. In addition, there are many examples of isocyanide-supported complexes where the isocyanide serves as a chromophoric ligand, meaning the low-energy excited states that are important in the photochemistry are partially or completely localized on the isocyanide. Finally, an emerging trend in the design of luminescent compounds is to use the isocyanide as an electrophilic precursor, converted to an acyclic carbene by nucleophilic addition which imparts certain photophysical advantages. This Perspective aims to show the diverse roles played by isocyanides in the design of luminescent compounds, showcasing the recent developments that have led to a substantial growth in fundamental knowledge, function, and applications related to photoluminescence.
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Affiliation(s)
- Gregory D Sutton
- University of Houston, Department of Chemistry, 3585 Cullen Blvd., Room 112, Houston, TX 77204-5003, USA.
| | - Morris E Olumba
- University of Houston, Department of Chemistry, 3585 Cullen Blvd., Room 112, Houston, TX 77204-5003, USA.
| | - Yennie H Nguyen
- University of Houston, Department of Chemistry, 3585 Cullen Blvd., Room 112, Houston, TX 77204-5003, USA.
| | - Thomas S Teets
- University of Houston, Department of Chemistry, 3585 Cullen Blvd., Room 112, Houston, TX 77204-5003, USA.
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40
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Fajardo J, Barth AT, Morales M, Takase MK, Winkler JR, Gray HB. Photoredox Catalysis Mediated by Tungsten(0) Arylisocyanides. J Am Chem Soc 2021; 143:19389-19398. [PMID: 34756036 DOI: 10.1021/jacs.1c07617] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
W(CNAr)6 (CNAr = arylisocyanide) photoreductants catalyze base-promoted homolytic aromatic substitution (BHAS) of 1-(2-iodobenzyl)-pyrrole in deuterated benzene. Moderate to high efficiencies correlate with W(CNAr)6 excited-state reduction potentials upon one-photon 445 nm excitation, with 10 mol % loading of the most powerful photoreductants W(CNDipp)6 (CNDipp = 2,6-diisopropylphenylisocyanide) and W(CNDippPhOMe3)6 (CNDippPhOMe3 = 4-(3,4,5-trimethoxyphenyl)-2,6-diisopropylphenylisocyanide) affording nearly complete conversion. Stern-Volmer quenching experiments indicated that catalysis is triggered by substrate reductive dehalogenation. Taking advantage of the large two-photon absorption (TPA) cross sections of W(CNAr)6 complexes, we found that photocatalysis can be driven with femtosecond-pulsed 810 nm excitation. For both one- and two-photon excitation, photocatalysis was terminated by the formation of seven-coordinate WII-diiodo [WI2(CNAr)5] complexes. Notably, we discovered that W(CNDipp)6 can be regenerated by chemical reduction of WI2(CNDipp)5 with excess ligand present in solution.
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Affiliation(s)
- Javier Fajardo
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Alexandra T Barth
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Maryann Morales
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Michael K Takase
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Jay R Winkler
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States
| | - Harry B Gray
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, United States
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41
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Wegeberg C, Wenger OS. Luminescent First-Row Transition Metal Complexes. JACS AU 2021; 1:1860-1876. [PMID: 34841405 PMCID: PMC8611671 DOI: 10.1021/jacsau.1c00353] [Citation(s) in RCA: 108] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Indexed: 05/25/2023]
Abstract
Precious and rare elements have traditionally dominated inorganic photophysics and photochemistry, but now we are witnessing a paradigm shift toward cheaper and more abundant metals. Even though emissive complexes based on selected first-row transition metals have long been known, recent conceptual breakthroughs revealed that a much broader range of elements in different oxidation states are useable for this purpose. Coordination compounds of V, Cr, Mn, Fe, Co, Ni, and Cu now show electronically excited states with unexpected reactivity and photoluminescence behavior. Aside from providing a compact survey of the recent conceptual key advances in this dynamic field, our Perspective identifies the main design strategies that enabled the discovery of fundamentally new types of 3d-metal-based luminophores and photosensitizers operating in solution at room temperature.
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42
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Börner M, Klose J, Gutierrez Suburu ME, Strassert CA, Yang F, Monakhov KY, Abel B, Kersting B. Synthesis and Characterisation of Luminescent [Cr III 2 L(μ-carboxylato)] 3+ Complexes with High-Spin S=3 Ground States (L=N 6 S 2 donor ligand). Chemistry 2021; 27:14899-14910. [PMID: 34490947 PMCID: PMC8596867 DOI: 10.1002/chem.202102079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Indexed: 01/02/2023]
Abstract
The synthesis, structure, magnetic, and photophysical properties of two dinuclear, luminescent, mixed-ligand [CrIII 2 L(O2 CR)]3+ complexes (R=CH3 (1), Ph (2)) of a 24-membered binucleating hexa-aza-dithiophenolate macrocycle (L)2- are presented. X-ray crystallographic analysis reveals an edge-sharing bioctahedral N3 Cr(μ-SR)2 (μ1,3 -O2 CR)CrN3 core structure with μ1,3 -bridging carboxylate groups. A ferromagnetic superexchange interaction between the electron spins of the Cr3+ ions leads to a high-spin (S=3) ground state. The coupling constants (J=+24.2(1) cm-1 (1), +34.8(4) cm-1 (2), H=-2JS1 S2 ) are significantly larger than in related bis-μ-alkoxido-μ-carboxylato structures. DFT calculations performed on both complexes reproduce both the sign and strength of the exchange interactions found experimentally. Frozen methanol-dichloromethane 1 : 1 solutions of 1 and 2 luminesce at 750 nm when excited into the 4 LMCT state on the 4 A2 → 2 T1 (ν2 ) bands (λexc =405 nm). The absolute quantum yields (ΦL ) for 1 and 2 were found to be strongly temperature dependent. At 77 K in frozen MeOH/CH2 Cl2 glasses, ΦL =0.44±0.02 (for 1), ΦL =0.45±0.02 (for 2).
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Affiliation(s)
- Martin Börner
- Institut für Anorganische ChemieUniversität LeipzigJohannisallee 2904103LeipzigGermany
- Leibniz Institut für OberflächenmodifizierungPermoserstraße 1504318LeipzigGermany
| | - Jennifer Klose
- Institut für Anorganische ChemieUniversität LeipzigJohannisallee 2904103LeipzigGermany
| | - Matias E. Gutierrez Suburu
- Institut für Anorganische und Analytische ChemieCiMICSoNWestfälische Wilhelms-Universität MünsterCorrensstraße 28/3048149MünsterGermany
- CeNTechWestfälische Wilhelms-Universität MünsterHeisenbergstraße 1148149MünsterGermany
| | - Cristian A. Strassert
- Institut für Anorganische und Analytische ChemieCiMICSoNWestfälische Wilhelms-Universität MünsterCorrensstraße 28/3048149MünsterGermany
- CeNTechWestfälische Wilhelms-Universität MünsterHeisenbergstraße 1148149MünsterGermany
| | - Fangshun Yang
- Leibniz Institut für OberflächenmodifizierungPermoserstraße 1504318LeipzigGermany
| | - Kirill Yu. Monakhov
- Leibniz Institut für OberflächenmodifizierungPermoserstraße 1504318LeipzigGermany
| | - Bernd Abel
- Leibniz Institut für OberflächenmodifizierungPermoserstraße 1504318LeipzigGermany
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische ChemieUniversität LeipzigLinnéstrasse 204103LeipzigGermany
| | - Berthold Kersting
- Institut für Anorganische ChemieUniversität LeipzigJohannisallee 2904103LeipzigGermany
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43
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Affiliation(s)
- Katja Heinze
- Department of Chemistry, Johannes Gutenberg University of Mainz, Mainz, Germany.
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44
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Aydogan A, Bangle RE, Cadranel A, Turlington MD, Conroy DT, Cauët E, Singleton ML, Meyer GJ, Sampaio RN, Elias B, Troian-Gautier L. Accessing Photoredox Transformations with an Iron(III) Photosensitizer and Green Light. J Am Chem Soc 2021; 143:15661-15673. [PMID: 34529421 DOI: 10.1021/jacs.1c06081] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Efficient excited-state electron transfer between an iron(III) photosensitizer and organic electron donors was realized with green light irradiation. This advance was enabled by the use of the previously reported iron photosensitizer, [Fe(phtmeimb)2]+ (phtmeimb = {phenyl[tris(3-methyl-imidazolin-2-ylidene)]borate}, that exhibited long-lived and luminescent ligand-to-metal charge-transfer (LMCT) excited states. A benchmark dehalogenation reaction was investigated with yields that exceed 90% and an enhanced stability relative to the prototypical photosensitizer [Ru(bpy)3]2+. The initial catalytic step is electron transfer from an amine to the photoexcited iron sensitizer, which is shown to occur with a large cage-escape yield. For LMCT excited states, this reductive electron transfer is vectorial and may be a general advantage of Fe(III) photosensitizers. In-depth time-resolved spectroscopic methods, including transient absorption characterization from the ultraviolet to the infrared regions, provided a quantitative description of the catalytic mechanism with associated rate constants and yields.
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Affiliation(s)
- Akin Aydogan
- Université Catholique de Louvain (UCLouvain), Institut de la Matière Condensée et des Nanosciences (IMCN), Molecular Chemistry, Materials and Catalysis (MOST), Place Louis Pasteur 1, bte L4.01.02, 1348 Louvain-la-Neuve, Belgium
| | - Rachel E Bangle
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Alejandro Cadranel
- Department of Chemistry and Pharmacy, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany.,Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina.,CONICET - Universidad de Buenos Aires. Instituto de Química Física de Materiales, Medio Ambiente y Energía (INQUIMAE), Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
| | - Michael D Turlington
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Daniel T Conroy
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Emilie Cauët
- Spectroscopy, Quantum Chemistry and Atmospheric Remote Sensing (CP 160/09), Université Libre de Bruxelles, 50 av. F. D. Roosevelt, B-1050 Brussels, Belgium
| | - Michael L Singleton
- Université Catholique de Louvain (UCLouvain), Institut de la Matière Condensée et des Nanosciences (IMCN), Molecular Chemistry, Materials and Catalysis (MOST), Place Louis Pasteur 1, bte L4.01.02, 1348 Louvain-la-Neuve, Belgium
| | - Gerald J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Renato N Sampaio
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Benjamin Elias
- Université Catholique de Louvain (UCLouvain), Institut de la Matière Condensée et des Nanosciences (IMCN), Molecular Chemistry, Materials and Catalysis (MOST), Place Louis Pasteur 1, bte L4.01.02, 1348 Louvain-la-Neuve, Belgium
| | - Ludovic Troian-Gautier
- Université Catholique de Louvain (UCLouvain), Institut de la Matière Condensée et des Nanosciences (IMCN), Molecular Chemistry, Materials and Catalysis (MOST), Place Louis Pasteur 1, bte L4.01.02, 1348 Louvain-la-Neuve, Belgium.,Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States.,Laboratoire de Chimie Organique, Université Libre de Bruxelles (ULB), CP 160/06, 50 avenue F.D. Roosevelt, 1050 Brussels, Belgium
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45
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Wegeberg C, Häussinger D, Wenger OS. Pyrene-Decoration of a Chromium(0) Tris(diisocyanide) Enhances Excited State Delocalization: A Strategy to Improve the Photoluminescence of 3d 6 Metal Complexes. J Am Chem Soc 2021; 143:15800-15811. [PMID: 34516734 DOI: 10.1021/jacs.1c07345] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
There is a long-standing interest in iron(II) complexes that emit from metal-to-ligand charge transfer (MLCT) excited states, analogous to ruthenium(II) polypyridines. The 3d6 electrons of iron(II) are exposed to a relatively weak ligand field, rendering nonradiative relaxation of MLCT states via metal-centered excited states undesirably efficient. For isoelectronic chromium(0), chelating diisocyanide ligands recently provided access to very weak MLCT emission in solution at room temperature. Here, we present a concept that boosts the luminescence quantum yield of a chromium(0) isocyanide complex by nearly 2 orders of magnitude, accompanied by a significant increase of the MLCT lifetime. Pyrene units in the diisocyanide ligand backbone lead to an enlarged π-conjugation system and to a strongly delocalized MLCT state, from which nonradiative relaxation is less dominant despite a sizable redshift of the emission. While the pyrene moiety is electronically coupled to the core of the chromium(0) complex in the excited state, UV-vis absorption and 2D NMR spectroscopy show that this is not the case in the ground state. Luminescence lifetimes and quantum yields for our pyrenyl-decorated chromium(0) complex exhibit an unusual bell-shaped dependence on solvent polarity, indicative of two counteracting effects governing the MLCT deactivation. These two effects are identified as predominant deactivation either through an energetically nearby lying metal-centered state in the most apolar solvents, or alternatively via direct nonradiative relaxation to the ground state following the energy gap law in more polar solvents. This is the first example of a 3d6 MLCT emitter to benefit from an increased π-conjugation network.
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Affiliation(s)
- Christina Wegeberg
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Daniel Häussinger
- 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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46
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Boden P, Di Martino‐Fumo P, Bens T, Steiger S, Albold U, Niedner‐Schatteburg G, Gerhards M, Sarkar B. NIR-Emissive Chromium(0), Molybdenum(0), and Tungsten(0) Complexes in the Solid State at Room Temperature. Chemistry 2021; 27:12959-12964. [PMID: 34237175 PMCID: PMC8519045 DOI: 10.1002/chem.202102208] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Indexed: 12/15/2022]
Abstract
The development of NIR emitters based on earth-abundant elements is an important goal in contemporary science. We present here Cr(0), Mo(0), and W(0) carbonyl complexes with a pyridyl-mesoionic carbene (MIC) based ligand. A detailed photophysical investigation shows that all the complexes exhibit dual emissions in the VIS and in the NIR region. The emissive excited states are assigned to two distinct triplet states by time-resolved emission and step-scan FTIR spectroscopy at variable temperature, supported by density functional theory. In particular, the NIR emissive triplet state exhibits unprecedented lifetimes of up to 600±10 ns and quantum yields reaching 1.7 ⋅ 10-4 at room temperature. These are the first examples of Cr(0), Mo(0) and W(0) complexes that emit in the NIR II region.
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Affiliation(s)
- Pit Boden
- Department of Chemistry and Research Center OptimasTU KaiserslauternErwin-Schrödinger-Straße 5267663KaiserslauternGermany
| | - Patrick Di Martino‐Fumo
- Department of Chemistry and Research Center OptimasTU KaiserslauternErwin-Schrödinger-Straße 5267663KaiserslauternGermany
| | - Tobias Bens
- Chair of Inorganic Coordination ChemistryInstitute of Inorganic ChemistryUniversity of StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Sophie Steiger
- Department of Chemistry and Research Center OptimasTU KaiserslauternErwin-Schrödinger-Straße 5267663KaiserslauternGermany
| | - Uta Albold
- Institute of Chemistry and BiochemistryFreie Universität BerlinFabeckstraße 34–3614195BerlinGermany
| | - Gereon Niedner‐Schatteburg
- Department of Chemistry and Research Center OptimasTU KaiserslauternErwin-Schrödinger-Straße 5267663KaiserslauternGermany
| | - Markus Gerhards
- Department of Chemistry and Research Center OptimasTU KaiserslauternErwin-Schrödinger-Straße 5267663KaiserslauternGermany
| | - Biprajit Sarkar
- Chair of Inorganic Coordination ChemistryInstitute of Inorganic ChemistryUniversity of StuttgartPfaffenwaldring 5570569StuttgartGermany
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47
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Lu J, Pan Q, Zhu S, Liu R, Zhu H. Ligand-Mediated Photophysics Adjustability in Bis-tridentate Ir(III) Complexes and Their Application in Efficient Optical Limiting Materials. Inorg Chem 2021; 60:12835-12846. [PMID: 34428896 DOI: 10.1021/acs.inorgchem.1c01142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A family of novel bis-tridentate Ir(III) complexes (Ir1-Ir5) incorporating both functional N∧C∧N-type ligands (L1-L5) and N∧N∧C-type ligand (L0) were synthesized attentively and characterized scientifically. The crystalline structures of Ir1, Ir3 and Ir4 were resoundingly confirmed by XRD. With the aid of experimental and theoretical methods, their photophysical properties at transient and steady states were scientifically investigated. The broadband charge-transfer absorption for these aforementioned Ir(III) complexes is up to 600 nm as shown in the UV-visible absorption spectrum. The emission lifetimes of their excited states are good. Between the visible and near-infrared regions, Ir1-Ir5 possessed powerful excited-state absorption. Hence, a remarkably robust reverse saturable absorption (RSA) process can occur once the complexes are irradiated by a 532 nm laser. The RSA effect follows the descending order: Ir3 > Ir5 > Ir4 ≈ Ir1 > Ir2. To sum up, modifying electron-donating units (-OCH3) and large π-conjugated units to the pyridyl N∧C∧N-type ligands is a systematic way to markedly raise the RSA effect. Therefore, these octahedral bis-tridentate Ir(III) complexes are potentially state-of-the-art optical limiting (OPL) materials.
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Affiliation(s)
- Jiapeng Lu
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Qianqian Pan
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Senqiang Zhu
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Rui Liu
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Hongjun Zhu
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
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48
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Dorn M, Kalmbach J, Boden P, Kruse A, Dab C, Reber C, Niedner-Schatteburg G, Lochbrunner S, Gerhards M, Seitz M, Heinze K. Ultrafast and long-time excited state kinetics of an NIR-emissive vanadium(iii) complex I: synthesis, spectroscopy and static quantum chemistry. Chem Sci 2021; 12:10780-10790. [PMID: 34476059 PMCID: PMC8372323 DOI: 10.1039/d1sc02137k] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 07/07/2021] [Indexed: 12/11/2022] Open
Abstract
In spite of intense, recent research efforts, luminescent transition metal complexes with Earth-abundant metals are still very rare owing to the small ligand field splitting of 3d transition metal complexes and the resulting non-emissive low-energy metal-centered states. Low-energy excited states decay efficiently non-radiatively, so that near-infrared emissive transition metal complexes with 3d transition metals are even more challenging. We report that the heteroleptic pseudo-octahedral d2-vanadium(iii) complex VCl3(ddpd) (ddpd = N,N'-dimethyl-N,N'-dipyridine-2-yl-pyridine-2,6-diamine) shows near-infrared singlet → triplet spin-flip phosphorescence maxima at 1102, 1219 and 1256 nm with a lifetime of 0.5 μs at room temperature. Band splitting, ligand deuteration, excitation energy and temperature effects on the excited state dynamics will be discussed on slow and fast timescales using Raman, static and time-resolved photoluminescence, step-scan FTIR and fs-UV pump-vis probe spectroscopy as well as photolysis experiments in combination with static quantum chemical calculations. These results inform future design strategies for molecular materials of Earth-abundant metal ions exhibiting spin-flip luminescence and photoinduced metal-ligand bond homolysis.
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Affiliation(s)
- Matthias Dorn
- Department of Chemistry, Johannes Gutenberg University of Mainz Duesbergweg 10-14 55128 Mainz Germany
| | - Jens Kalmbach
- Institute of Inorganic Chemistry, University of Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
| | - Pit Boden
- Department of Chemistry and Research Center Optimas, Technical University Kaiserslautern Erwin-Schrödinger-Straße 67663 Kaiserslautern Germany
| | - Ayla Kruse
- Institute for Physics, Department of Life, Light and Matter, University of Rostock 18051 Rostock Germany
| | - Chahinez Dab
- Département de chimie, Université de Montréal Montréal Québec H3C 3J7 Canada
| | - Christian Reber
- Département de chimie, Université de Montréal Montréal Québec H3C 3J7 Canada
| | - Gereon Niedner-Schatteburg
- Department of Chemistry and Research Center Optimas, Technical University Kaiserslautern Erwin-Schrödinger-Straße 67663 Kaiserslautern Germany
| | - Stefan Lochbrunner
- Institute for Physics, Department of Life, Light and Matter, University of Rostock 18051 Rostock Germany
| | - Markus Gerhards
- Department of Chemistry and Research Center Optimas, Technical University Kaiserslautern Erwin-Schrödinger-Straße 67663 Kaiserslautern Germany
| | - Michael Seitz
- Institute of Inorganic Chemistry, University of Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany
| | - Katja Heinze
- Department of Chemistry, Johannes Gutenberg University of Mainz Duesbergweg 10-14 55128 Mainz Germany
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Zobel JP, Knoll T, González L. Ultrafast and long-time excited state kinetics of an NIR-emissive vanadium(iii) complex II. Elucidating triplet-to-singlet excited-state dynamics. Chem Sci 2021; 12:10791-10801. [PMID: 34476060 PMCID: PMC8372553 DOI: 10.1039/d1sc02149d] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 05/25/2021] [Indexed: 11/21/2022] Open
Abstract
We report the non-adiabatic dynamics of VIIICl3(ddpd), a complex based on the Earth-abundant first-row transition metal vanadium with a d2 electronic configuration which is able to emit phosphorescence in solution in the near-infrared spectral region. Trajectory surface-hopping dynamics based on linear vibronic coupling potentials obtained with CASSCF provide molecular-level insights into the intersystem crossing from triplet to singlet metal-centered states. While the majority of the singlet population undergoes back-intersystem crossing to the triplet manifold, 1-2% remains stable during the 10 ps simulation time, enabling the phosphorescence described in Dorn et al. Chem. Sci., 2021, DOI: 10.1039/D1SC02137K. Competing with intersystem crossing, two different relaxation channels via internal conversion through the triplet manifold occur. The nuclear motion that drives the dynamics through the different electronic states corresponds mainly to the increase of all metal-ligand bond distances as well as the decrease of the angles of trans-coordinated ligand atoms. Both motions lead to a decrease in the ligand-field splitting, which stabilizes the interconfigurational excited states populated during the dynamics. Analysis of the electronic character of the states reveals that increasing and stabilizing the singlet population, which in turn can result in enhanced phosphorescence, could be accomplished by further increasing the ligand-field strength.
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Affiliation(s)
- J Patrick Zobel
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna Währingerstr. 19 1090 Vienna Austria
| | - Thomas Knoll
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna Währingerstr. 19 1090 Vienna Austria
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna Währingerstr. 19 1090 Vienna Austria
- Vienna Research Platform on Accelerating Photoreaction Discovery, University of Vienna Währingerstr. 19 1090 Vienna Austria
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50
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Luo Z, Liu Y, Tong KC, Chang XY, To WP, Che CM. Luminescent Platinum(II) Complexes with Bidentate Diacetylide Ligands: Structures, Photophysical Properties and Application Studies. Chem Asian J 2021; 16:2978-2992. [PMID: 34374225 DOI: 10.1002/asia.202100756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/07/2021] [Indexed: 01/19/2023]
Abstract
A series of platinum(II) complexes supported by terphenyl diacetylide as well as diimine or bis-N-heterocyclic carbene (NHC) ligands have been prepared. The diacetylide ligands adopt a cis coordination mode featuring non-planar terphenyl moieties as revealed by X-ray crystallographic analyses. The electrochemical, photophysical and photochemical properties of these platinum(II) complexes have been investigated. These platinum(II) diimine complexes show broad emission with peak maxima from 566 nm to 706 nm, with two of them having emission quantum yields >60% and lifetimes <2 μs in solutions at room temperature, whereas the platinum(II) diacetylide complexes having bis-N-heterocyclic carbene instead of diimine ligand display photoluminescence with quantum yields of up to 28% in solutions and excited state lifetimes of up to 62 μs at room temperature. Application studies revealed that one of the complexes can catalyze photoinduced aerobic dehydrogenation of alcohols and alkenes, and a relatively non-toxic water-soluble Pt(II) complex displays anti-angiogenic activity.
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Affiliation(s)
- Zaoli Luo
- Department Key Laboratory of Pesticide & Chemical Biology Ministry of Education and Chemical Biology Center College of Chemistry, Central China Normal University, Wuhan, 430079, P. R. China
| | - Yungen Liu
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, P. R. China
| | - Ka-Chung 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 SAR, P. R. China
| | - Xiao-Yong Chang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, P. R. 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 SAR, P. R. China
| | - Chi-Ming Che
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, P. R. 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 SAR, P. R. China.,HKU Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, 518057, P. R. China
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