1
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Eastham K, Kennedy ADW, Scottwell SØ, Bramham JE, Hardman S, Golovanov AP, Scattergood PA, Crowley JD, Elliott PIP. Photochemistry of Ru(II) Triazole Complexes with 6-Membered Chelate Ligands: Detection and Reactivity of Ligand-Loss Intermediates. Inorg Chem 2024; 63:9084-9097. [PMID: 38701516 PMCID: PMC11110011 DOI: 10.1021/acs.inorgchem.4c00251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 04/19/2024] [Accepted: 04/23/2024] [Indexed: 05/05/2024]
Abstract
Photochemical ligand release from metal complexes may be exploited in the development of novel photoactivated chemotherapy agents for the treatment of cancer and other diseases. Highly intriguing photochemical behavior is reported for two ruthenium(II) complexes bearing conformationally flexible 1,2,3-triazole-based ligands incorporating a methylene spacer to form 6-membered chelate rings. [Ru(bpy)2(pictz)]2+ (1) and [Ru(bpy)2(btzm)]2+ (2) (bpy = 2,2'-bipyridyl; pictz = 1-(picolyl)-4-phenyl-1,2,3-triazole; btzm = bis(4-phenyl-1,2,3-triazol-4-yl)methane) exhibit coordination by the triazole ring through the less basic N2 atom as a consequence of chelation and readily undergo photochemical release of the pictz and btzm ligands (ϕ = 0.079 and 0.091, respectively) in acetonitrile solution to form cis-[Ru(bpy)2(NCMe)2]2+ (3) in both cases. Ligand-loss intermediates of the form [Ru(bpy)2(κ1-pictz or κ1-btzm)(NCCD3)]2+ are detected by 1H NMR spectroscopy and mass spectrometry. Photolysis of 1 yields three ligand-loss intermediates with monodentate pictz ligands, two of which form through simple decoordination of either the pyridine or triazole donor with subsequent solvent coordination (4-tz(N2) and 4-py, respectively). The third intermediate, shown to be able to form photochemically directly from 1, arises through linkage isomerism in which the monodentate pictz ligand is coordinated by the triazole N3 atom (4-tz(N3)) with a comparable ligand-loss intermediate with an N3-bound κ1-btzm ligand also observed for 2.
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Affiliation(s)
- Katie Eastham
- Department
of Chemical Sciences and Centre for Functional Materials, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
| | - Aaron D. W. Kennedy
- Department
of Chemistry, University of Otago, PO Box 56, Dunedin 9054, New Zealand
- MacDiarmid
Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | - Synøve Ø. Scottwell
- Department
of Chemistry, University of Otago, PO Box 56, Dunedin 9054, New Zealand
- MacDiarmid
Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | - Jack E. Bramham
- Department
of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, Manchester M13 9PL, U.K.
| | - Samantha Hardman
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Alexander P. Golovanov
- Department
of Chemistry, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, Manchester M13 9PL, U.K.
| | - Paul A. Scattergood
- Department
of Chemical Sciences and Centre for Functional Materials, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
| | - James D. Crowley
- Department
of Chemistry, University of Otago, PO Box 56, Dunedin 9054, New Zealand
- MacDiarmid
Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | - Paul I. P. Elliott
- Department
of Chemical Sciences and Centre for Functional Materials, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
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2
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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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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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Hakkennes MLA, Meijer MS, Menzel JP, Goetz AC, Van Duijn R, Siegler MA, Buda F, Bonnet S. Ligand Rigidity Steers the Selectivity and Efficiency of the Photosubstitution Reaction of Strained Ruthenium Polypyridyl Complexes. J Am Chem Soc 2023. [PMID: 37294954 DOI: 10.1021/jacs.3c03543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
While photosubstitution reactions in metal complexes are usually thought of as dissociative processes poorly dependent on the environment, they are, in fact, very sensitive to solvent effects. Therefore, it is crucial to explicitly consider solvent molecules in theoretical models of these reactions. Here, we experimentally and computationally investigated the selectivity of the photosubstitution of diimine chelates in a series of sterically strained ruthenium(II) polypyridyl complexes in water and acetonitrile. The complexes differ essentially by the rigidity of the chelates, which strongly influenced the observed selectivity of the photosubstitution. As the ratio between the different photoproducts was also influenced by the solvent, we developed a full density functional theory modeling of the reaction mechanism that included explicit solvent molecules. Three reaction pathways leading to photodissociation were identified on the triplet hypersurface, each characterized by either one or two energy barriers. Photodissociation in water was promoted by a proton transfer in the triplet state, which was facilitated by the dissociated pyridine ring acting as a pendent base. We show that the temperature variation of the photosubstitution quantum yield is an excellent tool to compare theory with experiments. An unusual phenomenon was observed for one of the compounds in acetonitrile, for which an increase in temperature led to a surprising decrease in the photosubstitution reaction rate. We interpret this experimental observation based on complete mapping of the triplet hypersurface of this complex, revealing thermal deactivation to the singlet ground state through intersystem crossing.
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Affiliation(s)
- Matthijs L A Hakkennes
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, Leiden 2300 RA, The Netherlands
| | - Michael S Meijer
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, Leiden 2300 RA, The Netherlands
| | - Jan Paul Menzel
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, Leiden 2300 RA, The Netherlands
| | - Anne-Charlotte Goetz
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, Leiden 2300 RA, The Netherlands
| | - Roy Van Duijn
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, Leiden 2300 RA, The Netherlands
| | - Maxime A Siegler
- Department of Chemistry, Johns Hopkins University, 3400 N Charles Street, Baltimore, Maryland 21218, United States
| | - Francesco Buda
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, Leiden 2300 RA, The Netherlands
| | - Sylvestre Bonnet
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, Leiden 2300 RA, The Netherlands
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5
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Eastham K, Scattergood PA, Chu D, Boota RZ, Soupart A, Alary F, Dixon IM, Rice CR, Hardman SJO, Elliott PIP. Not All 3MC States Are the Same: The Role of 3MC cis States in the Photochemical N ∧N Ligand Release from [Ru(bpy) 2(N ∧N)] 2+ Complexes. Inorg Chem 2022; 61:19907-19924. [PMID: 36450138 DOI: 10.1021/acs.inorgchem.2c03146] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Ruthenium(II) complexes feature prominently in the development of agents for photoactivated chemotherapy; however, the excited-state mechanisms by which photochemical ligand release operates remain unclear. We report here a systematic experimental and computational study of a series of complexes [Ru(bpy)2(N∧N)]2+ (bpy = 2,2'-bipyridyl; N∧N = bpy (1), 6-methyl-2,2'-bipyridyl (2), 6,6'-dimethyl-2,2'-bipyridyl (3), 1-benzyl-4-(pyrid-2-yl)-1,2,3-triazole (4), 1-benzyl-4-(6-methylpyrid-2-yl)-1,2,3-triazole (5), 1,1'-dibenzyl-4,4'-bi-1,2,3-triazolyl (6)), in which we probe the contribution to the promotion of photochemical N∧N ligand release of the introduction of sterically encumbering methyl substituents and the electronic effect of replacement of pyridine by 1,2,3-triazole donors in the N∧N ligand. Complexes 2 to 6 all release the ligand N∧N on irradiation in acetonitrile solution to yield cis-[Ru(bpy)2(NCMe)2]2+, with resultant photorelease quantum yields that at first seem counter-intuitive and span a broad range. The data show that incorporation of a single sterically encumbering methyl substituent on the N∧N ligand (2 and 5) leads to a significantly enhanced rate of triplet metal-to-ligand charge-transfer (3MLCT) state deactivation but with little promotion of photoreactivity, whereas replacement of pyridine by triazole donors (4 and 6) leads to a similar rate of 3MLCT deactivation but with much greater photochemical reactivity. The data reported here, discussed in conjunction with previously reported data on related complexes, suggest that monomethylation in 2 and 5 sterically inhibits the formation of a 3MCcis state but promotes the population of 3MCtrans states which rapidly deactivate 3MLCT states and are prone to mediating ground-state recovery. On the other hand, increased photochemical reactivity in 4 and 6 seems to stem from the accessibility of 3MCcis states. The data provide important insights into the excited-state mechanism of photochemical ligand release by Ru(II) tris-bidentate complexes.
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Affiliation(s)
- Katie Eastham
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Paul A Scattergood
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.,Centre for Functional Materials, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Danny Chu
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Rayhaan Z Boota
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.,Centre for Functional Materials, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Adrien Soupart
- Laboratoire de Chimie et Physique Quantiques, UMR 5626 CNRS/Université Toulouse 3─Paul Sabatier, Université de Toulouse, 118 route de Narbonne, Toulouse 31062, France
| | - Fabienne Alary
- Laboratoire de Chimie et Physique Quantiques, UMR 5626 CNRS/Université Toulouse 3─Paul Sabatier, Université de Toulouse, 118 route de Narbonne, Toulouse 31062, France
| | - Isabelle M Dixon
- Laboratoire de Chimie et Physique Quantiques, UMR 5626 CNRS/Université Toulouse 3─Paul Sabatier, Université de Toulouse, 118 route de Narbonne, Toulouse 31062, France
| | - Craig R Rice
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Samantha J O Hardman
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K
| | - Paul I P Elliott
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.,Centre for Functional Materials, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
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6
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Francis S, Rice CR, Scattergood PA, Elliott PIP. Synthesis and characterisation of group 8 tris(1-benzyl-1,2,3-triazol-4-yl)- p-anisolylmethane complexes. Dalton Trans 2022; 51:13692-13702. [PMID: 36001010 DOI: 10.1039/d2dt02503e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The tris(1,2,3-triazol-4-yl)methane framework offers a highly versatile architecture for ligand design, yet the coordination chemistry of this class of ligand remains largely unexplored. We report here the synthesis and characterisation of the homoleptic complexes [M(ttzm)2](PF6)2 (ttzm = tris(1-benzyl-1,2,3-triazol-4-yl)-p-anisolylmethane; M = Fe (Fe), Ru (Ru), Os (Os)). Initial attempts to prepare Ru by reaction of [Ru(p-cymene)Cl2]2 and ttzm also led to the isolation of the heteroleptic complex [Ru(p-cymene)(ttzm)](PF6)2. The structures of [Ru(p-cymene)(ttzm)](PF6)2, [Fe(ttzm)2]2+ (as its BPh4- salt) and Os were solved by X-ray diffraction. The homoleptic Fe(II) and Os(II) containing cations adopt distorted octahedral geometries due to the steric interactions between the ansiole and triazole rings of the ttzm ligands. The homoleptic complexes all adopt a low-spin d6 configuration and exhibit reversible M(II)/M(III) processes (+0.35 to +0.72 V vs. Fc/Fc+). These oxidation processes are cathodically shifted relative to those of related hexatriazole donor based complexes with density functional theory (DFT) calculations showing the metal d-orbitals are destabilised through a π-donor contribution from the triazole rings. The complexes all show prominent UV-visible absorption bands between 350 and 450 nm assigned to transitions of 1MLCT character. Whilst none of the homoleptic complexes are emissive in room temperature fluid solutions, Os is emissive at 77 K in an EtOH/MeOH glass (λmax 472 nm).
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Affiliation(s)
- Samuel Francis
- Department of Chemical Sciences & Centre for Functional Materials, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
| | - Craig R Rice
- Department of Chemical Sciences & Centre for Functional Materials, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
| | - Paul A Scattergood
- Department of Chemical Sciences & Centre for Functional Materials, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
| | - Paul I P Elliott
- Department of Chemical Sciences & Centre for Functional Materials, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
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7
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Photosubstitution reaction of a bidentate ligand in a Ru(II) complex in aqueous solution. COMPUT THEOR CHEM 2022. [DOI: 10.1016/j.comptc.2022.113745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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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: 13] [Impact Index Per Article: 6.5] [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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9
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Flint KL, Huang DM, Linder-Patton OM, Sumby CJ, Keene FR. Synthesis of Triple‐Stranded Diruthenium(II) Compounds. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202200225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Kate L. Flint
- The University of Adelaide Chemistry 5005 Adelaide AUSTRALIA
| | - David M. Huang
- The University of Adelaide Chemistry 5005 Adelaide AUSTRALIA
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10
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Boota RZ, Hardman SJO, Ashton GP, Rice CR, Scattergood PA, Elliott PIP. Photochemistry of Heteroleptic 1,4,5,8-Tetraazaphenanthrene- and Bi-1,2,3-triazolyl-Containing Ruthenium(II) Complexes. Inorg Chem 2021; 60:15768-15781. [PMID: 34612633 DOI: 10.1021/acs.inorgchem.1c02441] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Diimine metal complexes have significant relevance in the development of photodynamic therapy (PDT) and photoactivated chemotherapy (PACT) applications. In particular, complexes of the TAP ligand (1,4,5,8-tetraazaphenanthrene) are known to lead to photoinduced oxidation of DNA, while TAP- and triazole-based complexes are also known to undergo photochemical ligand release processes relevant to PACT. The photophysical and photochemical properties of heteroleptic complexes [Ru(TAP)n(btz)3-n]2+ (btz = 1,1'-dibenzyl-4,4'-bi-1,2,3-triazolyl, n = 1 (1), 2 (2)) have been explored. Upon irradiation in acetonitrile, 1 displays analogous photochemistry to that previously observed for [Ru(bpy)(btz)2]2+ (bpy = 2,2'-bipyridyl) and generates trans-[Ru(TAP)(btz)(NCMe)2]2+ (5), which has been crystallographically characterized, with the observation of the ligand-loss intermediate trans-[Ru(TAP)(κ2-btz)(κ1-btz)(NCMe)]2+ (4). Complex 2 displays more complicated photochemical behavior with not only preferential photorelease of btz to form cis-[Ru(TAP)2(NCMe)2]2+ (6) but also competitive photorelease of TAP to form 5. Free TAP is then taken up by 6 to form [Ru(TAP)3]2+ (3) with the proportion of 5 and 3 observed to progressively increase during prolonged photolysis. Data suggest a complex set of reversible photochemical ligand scrambling processes in which 2 and 3 are interconverted. Computational DFT calculations have enabled optimization of geometries of the pro-trans 3MCcis states with repelled btz or TAP ligands crucial for the formation of 5 from 1 and 2, respectively, lending weight to recent evidence that such 3MCcis states play an important mechanistic role in the rich photoreactivity of Ru(II) diimine complexes.
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Affiliation(s)
- Rayhaan Z Boota
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Samantha J O Hardman
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K
| | - Gage P Ashton
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Craig R Rice
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Paul A Scattergood
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Paul I P Elliott
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
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11
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Soriano-Díaz I, Ortí E, Giussani A. On the Importance of Ligand-Centered Excited States in the Emission of Cyclometalated Ir(III) Complexes. Inorg Chem 2021; 60:13222-13232. [PMID: 34492762 PMCID: PMC8424641 DOI: 10.1021/acs.inorgchem.1c01604] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
![]()
The photophysical
behavior of the cyclometalating Ir(III) complexes
[Ir(ppy)2(bpy)]+, where Hppy is 2-phenylpyridine
and bpy is 2,2′-bipyridine (complex 1), and [Ir(diFppy)2(dtb-bpy)]+, where diFppy is 2-(2,4-difluorophenyl)pyridine
and dtb-bpy is 4,4′-di-tert-butyl-2,2′-bipyridine
(complex 2), has been theoretically investigated by performing
density functional theory calculations. The two complexes share the
same molecular skeleton, complex 2 being derived from
complex 1 through the addition of fluoro and tert-butyl substituents, but present notable differences
in their photophysical properties. The remarkable difference in their
emission quantum yields (0.196 for complex 1 in dichloromethane
and 0.71 for complex 2 in acetonitrile) has been evaluated
by characterizing both radiative and nonradiative decay paths. It
has emerged that the probability of decaying through the nonradiative
triplet metal-centered state, normally associated with the loss of
the emission quantum yield, does not appear to be the reason behind
the reported substantially different emission efficiency. A more critical
factor appears to be the ability of complex 2 to emit
from both the usual metal-to-ligand charge-transfer state and from
two additional ligand-centered states, as supported by the fact that
the respective minima belong to the potential energy surface of the
lowest triplet T1 state and that their phosphorescence
lifetimes are in the same order of magnitude. In contrast, the emission
of complex 1 can be originated only from the metal-to-ligand
charge-transfer state, being the only emissive T1 minimum.
The results constitute a significant case in which the emission from
ligand-centered states is the key for determining the high emission
quantum yield of a complex. The
reasons behind the significant increase in the emission
quantum yield of the [Ir(diFppy)2(dtb-bpy)]+ complex with respect to [Ir(ppy)2(bpy)]+ are
rationalized on the basis of DFT, TDDFT, and TDDFT-SOC calculations,
revealing the key role that low-lying LC states can play in the emission
properties of the complex.
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Affiliation(s)
- Iván Soriano-Díaz
- Instituto de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán 2, 46980 Paterna, Spain
| | - Enrique Ortí
- Instituto de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán 2, 46980 Paterna, Spain
| | - Angelo Giussani
- Instituto de Ciencia Molecular, Universidad de Valencia, Catedrático José Beltrán 2, 46980 Paterna, Spain
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12
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Dixon IM, Bonnet S, Alary F, Cuny J. Photoinduced Ligand Exchange Dynamics of a Polypyridyl Ruthenium Complex in Aqueous Solution. J Phys Chem Lett 2021; 12:7278-7284. [PMID: 34323082 DOI: 10.1021/acs.jpclett.1c01424] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The understanding of photoinduced ligand exchange mechanisms in polypyridyl ruthenium(II) complexes operating in aqueous solution is of crucial importance to rationalize their photoreactivity. Herein, we demonstrate that a synergetic use of ab initio molecular dynamics simulations and static calculations, both conducted at the DFT level, can provide a full understanding of photosubstitution mechanisms of a monodentate ligand by a solvent water molecule in archetypal ruthenium complexes in explicit water. The simulations show that the photoinduced loss of a monodentate ligand generates an unreactive 16-electron species in a hitherto undescribed pentacoordinated triplet excited state that converts, via an easily accessible crossing point, to a reactive 16-electron singlet ground state, which combines with a solvent water molecule to yield the experimentally observed aqua complex in less than 10 ps. This work paves the way for the rational design of novel photoactive metal complexes relevant for biological applications.
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Affiliation(s)
- Isabelle M Dixon
- Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier, Laboratoire de Chimie et Physique Quantiques, 31062 Toulouse Cedex 9, France
| | - Sylvestre Bonnet
- Leiden Institute of Chemistry, Leiden University, 2300 RA Leiden, The Netherlands
| | - Fabienne Alary
- Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier, Laboratoire de Chimie et Physique Quantiques, 31062 Toulouse Cedex 9, France
| | - Jérôme Cuny
- Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier, Laboratoire de Chimie et Physique Quantiques, 31062 Toulouse Cedex 9, France
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13
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Ross DAW, Mapley JI, Cording AP, Vasdev RAS, McAdam CJ, Gordon KC, Crowley JD. 6,6'-Ditriphenylamine-2,2'-bipyridine: Coordination Chemistry and Electrochemical and Photophysical Properties. Inorg Chem 2021; 60:11852-11865. [PMID: 34311548 DOI: 10.1021/acs.inorgchem.1c01435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A 2,2'-bipyridine with bulky triphenylamine substituents in the 6 and 6' positions of the ligand (6,6'-ditriphenylamine-2,2'-bipyridine, 6,6'-diTPAbpy) was generated. Despite the steric bulk, the ligand readily formed bis(homoleptic) complexes with copper(I) and silver(I) ions. Unfortunately, efforts to use the 6,6'-diTPAbpy system to generate heteroleptic [Cu(6,6'-diTPAbpy)(bpy)]+ complexes were unsuccessful with only the [Cu(6,6'-diTPAbpy)2](PF6) complex observed. The 6,6'-diTPAbpy ligand could also be reacted with 6-coordinate metal ions that featured small ancillary ligands, namely, the [Re(CO)3Cl] and [Ru(CO)2Cl2] fragments. While the complexes could be formed in good yields, the steric bulk of the TPA units does alter the coordination geometry. This is most readily seen in the [(6,6'-diTPAbpy)Re(CO)3Cl] complex where the Re(I) ion is forced to sit 23° out of the plane formed by the bpy unit. The electrochemical and photophysical properties of the family of compounds were also examined. 6,6'-diTPAbpy exhibits a strong ILCT absorption band (356 nm, 50 mM-1 cm-1) which displays a small increase in intensity for the homoleptic complexes ([Cu(6,6'-diTPAbpy)2]+; 353 nm, 72 mM-1 cm-1, [Ag(6,6'-diTPAbpy)2]+; 353 nm, 75 mM-1 cm-1), despite containing 2 equiv of the ligand, attributed to an increased dihedral angle between the TPA and bpy moieties. For the 6-coordinate complexes the ILCT band is further decreased in intensity and overlaps with MLCT bands, consistent with a further increased TPA-bpy dihedral angle. Emission from the 1ILCT state is observed at 436 nm (τ = 4.4 ns) for 6,6'-diTPAbpy and does not shift for the Cu, Ag, and Re complexes, although an additional 3MLCT emission is observed for [Re(6,6'-diTPAbpy)(CO)3Cl] (640 nm, τ = 13.8 ns). No emission was observed for [Ru(6,6'-diTPAbpy)(CO)2Cl2]. Transient absorption measurements revealed the population of a 3ILCT state for the Cu and Ag complexes (τ = 80 ns). All assignments were supported by TD-DFT calculations and resonance Raman spectroscopic measurements.
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Affiliation(s)
- Daniel A W Ross
- Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand.,MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | - Joseph I Mapley
- Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand.,MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | - Andrew P Cording
- Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Roan A S Vasdev
- Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand.,MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | - C John McAdam
- Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Keith C Gordon
- Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand.,MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | - James D Crowley
- Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand.,MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
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14
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Dixon IM, Rat S, Sournia-Saquet A, Molnár G, Salmon L, Bousseksou A. On the Spin-State Dependence of Redox Potentials of Spin Crossover Complexes. Inorg Chem 2020; 59:18402-18406. [PMID: 33284611 DOI: 10.1021/acs.inorgchem.0c03043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Resistance switching properties of nanoscale junctions of spin crossover molecules have received recently much interest. In many cases, this property has been traced back to the variation of molecular orbital energies upon spin transition. However, one can also expect a substantial reorganization of the molecular structure due to charge localization, which calls for a better understanding of the relationship between the redox potential and the spin state of the molecule. To investigate this issue, we carried out a detailed density functional theory and variable temperature cyclic voltammetry investigation of the benchmark compound [Fe(HB(1,2,4-triazol-1-yl)3)2] in solution. We show that, for a correct thermodynamical picture, it is necessary to take into account the charge transfer-induced electronic and structural reorganization as well as spin equilibria in the oxidized and reduced species.
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Affiliation(s)
- Isabelle M Dixon
- Laboratoire de Chimie et Physique Quantiques, UMR 5626 CNRS/Université Toulouse 3-Paul Sabatier, Université de Toulouse, 118 route de Narbonne, 31062 Toulouse, France
| | - Sylvain Rat
- Laboratoire de Chimie de Coordination, UPR 8241, CNRS and Université de Toulouse, UPS, INP, 205 route de Narbonne, 31077 Toulouse, France
| | - Alix Sournia-Saquet
- Laboratoire de Chimie de Coordination, UPR 8241, CNRS and Université de Toulouse, UPS, INP, 205 route de Narbonne, 31077 Toulouse, France
| | - Gábor Molnár
- Laboratoire de Chimie de Coordination, UPR 8241, CNRS and Université de Toulouse, UPS, INP, 205 route de Narbonne, 31077 Toulouse, France
| | - Lionel Salmon
- Laboratoire de Chimie de Coordination, UPR 8241, CNRS and Université de Toulouse, UPS, INP, 205 route de Narbonne, 31077 Toulouse, France
| | - Azzedine Bousseksou
- Laboratoire de Chimie de Coordination, UPR 8241, CNRS and Université de Toulouse, UPS, INP, 205 route de Narbonne, 31077 Toulouse, France
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15
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Soupart A, Alary F, Heully JL, Elliott PIP, Dixon IM. Theoretical Study of the Full Photosolvolysis Mechanism of [Ru(bpy)3]2+: Providing a General Mechanistic Roadmap for the Photochemistry of [Ru(N^N)3]2+-Type Complexes toward Both Cis and Trans Photoproducts. Inorg Chem 2020; 59:14679-14695. [DOI: 10.1021/acs.inorgchem.0c01843] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Adrien Soupart
- Laboratoire de Chimie et Physique Quantiques, Université de Toulouse, CNRS, 118 route de Narbonne, 31062 Toulouse, France
| | - Fabienne Alary
- Laboratoire de Chimie et Physique Quantiques, Université de Toulouse, CNRS, 118 route de Narbonne, 31062 Toulouse, France
| | - Jean-Louis Heully
- Laboratoire de Chimie et Physique Quantiques, Université de Toulouse, CNRS, 118 route de Narbonne, 31062 Toulouse, France
| | - Paul I. P. Elliott
- Department of Chemistry and Centre for Functional Materials, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K
| | - Isabelle M. Dixon
- Laboratoire de Chimie et Physique Quantiques, Université de Toulouse, CNRS, 118 route de Narbonne, 31062 Toulouse, France
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16
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Soupart A, Alary F, Heully JL, Elliott PI, Dixon IM. Recent progress in ligand photorelease reaction mechanisms: Theoretical insights focusing on Ru(II) 3MC states. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2020.213184] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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17
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Abstract
A series of [Re(N^N)(CO)3(Cl)] (N^N = diimine) complexes based on 4-(pyrid-2-yl)-1,2,3-triazole (1), 1-benzyl-4-(pyrimidin-2-yl)-1,2,3-triazole (2), and 1-benzyl-4-(pyrazin-2-yl)-1,2,3-triazole (3) diimine ligands were prepared and their photophysical and electrochemical properties were characterized. The ligand-based reduction wave is shown to be highly sensitive to the nature of the triazole-based ligand, with the peak potential shifting by up to 600 mV toward more positive potential from 1 to 3. All three complexes are phosphorescent in solution at room temperature with λmax ranging from 540 nm (1) to 638 nm (3). Interestingly, the complexes appear to show inverted energy-gap law behaviour (τ = 43 ns for 1 versus 92 ns for 3), which is tentatively interpreted as reduced thermal accessibility of metal-centred (3MC) states from photoexcited metal to ligand charge transfer (3MLCT) states upon stabilisation of the N^N-centred lowest unoccupied molecular orbital (LUMO). The photophysical characterisation, supported by computational data, demonstrated a progressive stabilization of the LUMO from complex 1 to 3, which results in a narrowing of the HOMO–LUMO energy gap (HOMO = highest occupied molecular orbital) across the series and, correspondingly, red-shifted electronic absorption and photoluminescence spectra. The two complexes bearing pyridyl (1) and pyrimidyl (2) moieties, respectively, showed a modest ability to catalyse the electroreduction of CO2, with a peak potential at ca. −2.3 V versus Fc/Fc+. The catalytic wave that is observed in the cyclic voltammograms is slightly enhanced by the addition of water as a proton source.
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18
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On the Possible Coordination on a 3MC State Itself? Mechanistic Investigation Using DFT-Based Methods. INORGANICS 2020. [DOI: 10.3390/inorganics8020015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Understanding light-induced ligand exchange processes is key to the design of efficient light-releasing prodrugs or photochemically driven functional molecules. Previous mechanistic investigations had highlighted the pivotal role of metal-centered (MC) excited states in the initial ligand loss step. The question remains whether they are equally important in the subsequent ligand capture step. This article reports the mechanistic study of direct acetonitrile coordination onto a 3MC state of [Ru(bpy)3]2+, leading to [Ru(bpy)2(κ1-bpy)(NCMe)]2+ in a 3MLCT (metal-to-ligand charge transfer) state. Coordination of MeCN is indeed accompanied by the decoordination of one pyridine ring of a bpy ligand. As estimated from Nudged Elastic Band calculations, the energy barrier along the minimum energy path is 20 kcal/mol. Interestingly, the orbital analysis conducted along the reaction path has shown that creation of the metallic vacancy can be achieved by reverting the energetic ordering of key dσ* and bpy-based π* orbitals, resulting in the change of electronic configuration from 3MC to 3MLCT. The approach of the NCMe lone pair contributes to destabilizing the dσ* orbital by electrostatic repulsion.
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19
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Excited-State Relaxation in Luminescent Molybdenum(0) Complexes with Isocyanide Chelate Ligands. INORGANICS 2020. [DOI: 10.3390/inorganics8020014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Diisocyanide ligands with a m-terphenyl backbone provide access to Mo0 complexes exhibiting the same type of metal-to-ligand charge transfer (MLCT) luminescence as the well-known class of isoelectronic RuII polypyridines. The luminescence quantum yields and lifetimes of the homoleptic tris(diisocyanide) Mo0 complexes depend strongly on whether methyl- or tert-butyl substituents are placed in α-position to the isocyanide groups. The bulkier tert-butyl substituents lead to a molecular structure in which the three individual diisocyanides ligated to one Mo0 center are interlocked more strongly into one another than the ligands with the sterically less demanding methyl substituents. This rigidification limits the distortion of the complex in the emissive excited-state, causing a decrease of the nonradiative relaxation rate by one order of magnitude. Compared to RuII polypyridines, the molecular distortions in the luminescent 3MLCT state relative to the electronic ground state seem to be smaller in the Mo0 complexes, presumably due to delocalization of the MLCT-excited electron over greater portions of the ligands. Temperature-dependent studies indicate that thermally activated nonradiative relaxation via metal-centered excited states is more significant in these homoleptic Mo0 tris(diisocyanide) complexes than in [Ru(2,2′-bipyridine)3]2+.
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20
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Computational Assessment of MLCT versus MC Stabilities in First‐to‐Third‐Row d
6
Pseudo‐Octahedral Transition Metal Complexes. J Comput Chem 2019; 40:2377-2390. [DOI: 10.1002/jcc.26014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/11/2019] [Accepted: 06/11/2019] [Indexed: 11/07/2022]
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21
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Luis ET, Iranmanesh H, Beves JE. Photosubstitution reactions in ruthenium(II) trisdiimine complexes: Implications for photoredox catalysis. Polyhedron 2019. [DOI: 10.1016/j.poly.2018.11.057] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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22
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Keane PM, Tory J, Towrie M, Sazanovich IV, Cardin CJ, Quinn SJ, Hartl F, Kelly JM, Long C. Spectro-electrochemical Studies on [Ru(TAP) 2(dppz)] 2+-Insights into the Mechanism of its Photosensitized Oxidation of Oligonucleotides. Inorg Chem 2018; 58:663-671. [PMID: 30540448 DOI: 10.1021/acs.inorgchem.8b02859] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[Ru(TAP)2(dppz)]2+ (TAP = 1,4,5,8-tetraazaphenanthrene; dppz = dipyrido[3,2- a:2',3'- c]phenazine) is known to photo-oxidize guanine in DNA. Whether this oxidation proceeds by direct photoelectron transfer or by proton-coupled electron transfer is still unknown. To help distinguish between these mechanisms, spectro-electrochemical experiments have been carried out with [Ru(TAP)2(dppz)]2+ in acetonitrile. The UV-vis and mid-IR spectra obtained for the one-electron reduced product were compared to those obtained by picosecond transient absorption and time-resolved infrared experiments of [Ru(TAP)2(dppz)]2+ bound to guanine-containing DNA. An interesting feature of the singly reduced species is an electronic transition in the near-IR region (with λmax at 1970 and 2820 nm). Density functional and time-dependent density functional theory simulations of the vibrational and electronic spectra of [Ru(TAP)2(dppz)]2+, the reduced complex [Ru(TAP)2(dppz)]+, and four isomers of [Ru(TAP)(TAPH)(dppz)]2+ (a possible product of proton-coupled electron transfer) were performed. Significantly, these predict absorption bands at λ > 1900 nm (attributed to a ligand-to-metal charge-transfer transition) for [Ru(TAP)2(dppz)]+ but not for [Ru(TAP)(TAPH)(dppz)]2+. Both the UV-vis and mid-IR difference absorption spectra of the electrochemically generated singly reduced species [Ru(TAP)2(dppz)]+ agree well with the transient absorption and time-resolved infrared spectra previously determined for the transient species formed by photoexcitation of [Ru(TAP)2(dppz)]2+ intercalated in guanine-containing DNA. This suggests that the photochemical process in DNA proceeds by photoelectron transfer and not by a proton-coupled electron transfer process involving formation of [Ru(TAP)(TAPH)(dppz)]2+, as is proposed for the reaction with 5'-guanosine monophosphate. Additional infrared spectro-electrochemical measurements and density functional calculations have also been carried out on the free TAP ligand. These show that the TAP radical anion in acetonitrile also exhibits strong broad near-IR electronic absorption (λmax at 1750 and 2360 nm).
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Affiliation(s)
- Páraic M Keane
- School of Chemistry , University of Dublin, Trinity College , Dublin 2 , Ireland.,Department of Chemistry , University of Reading , Whiteknights, Reading RG6 6AD , United Kingdom
| | - Joanne Tory
- Department of Chemistry , University of Reading , Whiteknights, Reading RG6 6AD , United Kingdom
| | - Michael Towrie
- Science and Technology Facilities Council , Rutherford Appleton Laboratory, Research Complex at Harwell , Didcot, Oxfordshire OX11 0QX , United Kingdom
| | - Igor V Sazanovich
- Science and Technology Facilities Council , Rutherford Appleton Laboratory, Research Complex at Harwell , Didcot, Oxfordshire OX11 0QX , United Kingdom
| | - Christine J Cardin
- Department of Chemistry , University of Reading , Whiteknights, Reading RG6 6AD , United Kingdom
| | - Susan J Quinn
- School of Chemistry , University College Dublin , Belfield, Dublin 4 , Ireland
| | - František Hartl
- Department of Chemistry , University of Reading , Whiteknights, Reading RG6 6AD , United Kingdom
| | - John M Kelly
- School of Chemistry , University of Dublin, Trinity College , Dublin 2 , Ireland
| | - Conor Long
- School of Chemical Sciences , Dublin City University , Dublin 9 , Ireland
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23
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Findlay JA, Barnsley JE, Gordon KC, Crowley JD. Synthesis and Light-Induced Actuation of Photo-Labile 2-Pyridyl-1,2,3-Triazole Ru(bis-bipyridyl) Appended Ferrocene Rotors. Molecules 2018; 23:E2037. [PMID: 30110981 PMCID: PMC6222349 DOI: 10.3390/molecules23082037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 08/09/2018] [Accepted: 08/09/2018] [Indexed: 11/16/2022] Open
Abstract
To realise useful control over molecular motion in the future an extensive toolbox of both actionable molecules and stimuli-responsive units must be developed. Previously, our laboratory has reported 1,1'-disubstituted ferrocene (Fc) rotor units which assume a contracted/π-stacked conformation until complexation of cationic metal ions causes rotation about the Ferrocene (Fc) molecular 'ball-bearing'. Herein, we explore the potential of using the photochemical ejection of [Ru(2,2'-bipyridyl)₂]2+ units as a stimulus for the rotational contraction of new ferrocene rotor units. Fc rotors with both 'regular' and 'inverse' 2-pyridyl-1,2,3-triazole binding pockets and their corresponding [Ru(2,2'-bipyridyl)₂]2+ complexes were synthesised. The rotors and complexes were characterised using nuclear magnetic resonance (NMR) and ultraviolet (UV)-visible spectroscopies, Electro-Spray Ionisation Mass Spectrometry (ESI⁻MS), and electrochemistry. The 1,1'-disubstituted Fc ligands were shown to π-stack both in solution and solid state. Density Functional Theory (DFT) calculations (CAM-B3LYP/6-31G(d)) support the notion that complexation to [Ru(2,2'-bipyridyl)₂]2+ caused a rotation from the syn- to the anti-conformation. Upon photo-irradiation with UV light (254 nm), photo-ejection of the [Ru(2,2'-bipyridyl)₂(CH₃CN)₂]2+ units in acetonitrile was observed. The re-complexation of the [Ru(2,2'-bipyridyl)₂]2+ units could be achieved using acetone as the reaction solvent. However, the process was exceedingly slowly. Additionally, the Fc ligands slowly decomposed when exposed to UV irradiation meaning that only one extension and contraction cycle could be completed.
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Affiliation(s)
- James A Findlay
- Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, Otago, New Zealand.
| | - Jonathan E Barnsley
- Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, Otago, New Zealand.
| | - Keith C Gordon
- Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, Otago, New Zealand.
| | - James D Crowley
- Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, Otago, New Zealand.
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24
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Hosseinnejad T, Ebrahimpour-Malmir F, Fattahi B. Computational investigations of click-derived 1,2,3-triazoles as keystone ligands for complexation with transition metals: a review. RSC Adv 2018; 8:12232-12259. [PMID: 35539398 PMCID: PMC9079615 DOI: 10.1039/c8ra00283e] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 01/04/2019] [Accepted: 03/02/2018] [Indexed: 01/05/2023] Open
Abstract
In recent years, metal complexes of organo 1,2,3-triazole click-derived ligands have attracted significant attention as catalysts in many chemical transformations and also as biological and pharmaceutical active agents. Regarding the important applications of these metal-organo 1,2,3-triazole-based complexes, in this review, we focused on the recently reported investigations of the structural, electronic, and spectroscopic aspects of the complexation process in transition metal complexes of 1,2,3-triazole-based click ligands. In line with this, the coordination properties of these triazole-based click ligands with transition metals were studied via several quantum chemistry calculations. Moreover, considering the complexation process, we have presented comparative discussions between the computational results and the available experimental data.
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Affiliation(s)
- Tayebeh Hosseinnejad
- Department of Chemistry, Faculty of Physics & Chemistry, Alzahra University Vanak Tehran Iran +98-21-8804-1344 +98-9124775800
| | - Fatemeh Ebrahimpour-Malmir
- Department of Chemistry, Faculty of Physics & Chemistry, Alzahra University Vanak Tehran Iran +98-21-8804-1344 +98-9124775800
| | - Bahareh Fattahi
- Department of Chemistry, Faculty of Physics & Chemistry, Alzahra University Vanak Tehran Iran +98-21-8804-1344 +98-9124775800
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25
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Soupart A, Alary F, Heully JL, Elliott PIP, Dixon IM. Exploration of Uncharted 3PES Territory for [Ru(bpy)3]2+: A New 3MC Minimum Prone to Ligand Loss Photochemistry. Inorg Chem 2018; 57:3192-3196. [DOI: 10.1021/acs.inorgchem.7b03229] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Adrien Soupart
- Laboratoire de Chimie et Physique Quantiques, Université de Toulouse, CNRS, 118 route de Narbonne, 31062 Toulouse, France
| | - Fabienne Alary
- Laboratoire de Chimie et Physique Quantiques, Université de Toulouse, CNRS, 118 route de Narbonne, 31062 Toulouse, France
| | - Jean-Louis Heully
- Laboratoire de Chimie et Physique Quantiques, Université de Toulouse, CNRS, 118 route de Narbonne, 31062 Toulouse, France
| | - Paul I. P. Elliott
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, U.K
- Centre for Functional Materials, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, U.K
| | - Isabelle M. Dixon
- Laboratoire de Chimie et Physique Quantiques, Université de Toulouse, CNRS, 118 route de Narbonne, 31062 Toulouse, France
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26
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Soupart A, Dixon IM, Alary F, Heully JL. DFT rationalization of the room-temperature luminescence properties of Ru(bpy)
3
2+
and Ru(tpy)
2
2+
: 3MLCT–3MC minimum energy path from NEB calculations and emission spectra from VRES calculations. Theor Chem Acc 2018. [DOI: 10.1007/s00214-018-2216-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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27
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Scattergood PA, Elliott PIP. An unexpected journey from highly tunable phosphorescence to novel photochemistry of 1,2,3-triazole-based complexes. Dalton Trans 2017; 46:16343-16356. [DOI: 10.1039/c7dt03836d] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Complexes containing the humble 1,2,3-triazole ring moiety have enabled access to highly tunable with efficient phosphorescence but have also in facilitated access to novel photoreactive excited states yielding highly unusual photochemical reactivity.
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