1
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Dunbar MN, Steinke SJ, Piechota EJ, Turro C. Differences in Photophysical Properties and Photochemistry of Ru(II)-Terpyridine Complexes of CH 3CN and Pyridine. J Phys Chem A 2024; 128:599-610. [PMID: 38227956 DOI: 10.1021/acs.jpca.3c07432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
A series of 22 Ru(II) complexes of the type [Ru(tpy)(L)(L')]n+, where tpy is the tridentate ligand 2,2';6,2″-terpyridine, L represents bidentate ligands with varying electron-donating ability, and L' is acetonitrile (1a-11a) or pyridine (1b-11b), were investigated. The dissociation of acetonitrile occurs from the 3MLCT state in 1a-11a, such that it does not require the population of a 3LF state. Electrochemistry and spectroscopic data demonstrate that the ground states of these series do not differ significantly. Franck-Condon line-shape analysis of the 77 K emission data shows no significant differences between the emitting 3MLCT states in both series. Arrhenius analysis of the temperature dependence of 3MLCT lifetimes shows that the energy barrier (Ea) to thermally populating a 3LF state from a lower energy 3MLCT state is significantly higher in the pyridine than in the CH3CN series, consistent with the photostability of complexes 1b-11b, which do not undergo pyridine photodissociation under our experimental conditions. Importantly, these results demonstrate that ligand photodissociation of pyridine in 1b-11b does not take place directly from the 3MLCT state, as is the case for 1a-11a. These findings have potential impact on the rational design of complexes for a number of applications, including photochemotherapy, dye-sensitized solar cells, and photocatalysis.
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Affiliation(s)
- Marilyn N Dunbar
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Sean J Steinke
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Eric J Piechota
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Claudia Turro
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
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2
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Hernández‐Castillo D, Nau REP, Schmid M, Tschierlei S, Rau S, González L. Mehrere Triplett-Metall-zentrierte Jahn-Teller-Isomere bestimmen die temperaturabhängigen Lumineszenzlebensdauern in [Ru(bpy) 3] 2. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 135:e202308803. [PMID: 38529088 PMCID: PMC10962581 DOI: 10.1002/ange.202308803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Indexed: 03/27/2024]
Abstract
AbstractEin genaues Verständnis der Faktoren, welche die Lumineszenzlebensdauer von Übergangsmetallverbindungen bestimmen, ist für Anwendungen in der Photokatalyse und der photodynamischen Therapie von entscheidender Bedeutung. Die im Falle von [Ru(bpy)3]2+ (bpy=2,2’‐Bipyridin) allgemein akzeptierte Theorie besagt, dass die Emissionslebensdauer durch Optimierung der Energiebarriere zwischen dem emittierenden Triplett‐Zustand des Metall‐Liganden‐Ladungstransfers (3MLCT) und dem thermisch aktivierten Triplett‐Zustand des Metall‐Zentrums (3MC), oder der Energielücke zwischen beiden Zuständen gesteuert werden kann. Hier zeigen wir, dass dies nicht allgemeingültig ist. Darüber hinaus demonstrieren wir, dass die Betrachtung eines einzelnen Relaxationspfades, der vom energetisch niedrigsten Minimum aus bestimmt wird, zu falschen Vorhersagen der temperaturabhängigen Emissionslebensdauer führt. Stattdessen erhalten wir eine ausgezeichnete Übereinstimmung mit den experimentellen temperaturabhängigen Lebensdauern, wenn ein erweitertes kinetisches Modell herangezogen wird, welches alle Pfade im Zusammenhang mit mehreren Jahn–Teller‐Isomeren und ihren effektiven Reaktionsbarrieren beinhaltet. Diese Konzepte sind für das Design weiterer lumineszierender Übergangsmetallkomplexe mit individuell angepassten Emissionslebensdauern auf der Grundlage theoretischer Vorhersagen unerlässlich.
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Affiliation(s)
- David Hernández‐Castillo
- Institute of Theoretical ChemistryFaculty of ChemistryUniversity of ViennaWähringer Str. 171090ViennaAustria
- Doctoral School in Chemistry (DoSChem)University of ViennaWähringer Straße 421090ViennaAustria
| | - Roland E. P. Nau
- Institute of Inorganic Chemistry IUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | - Marie‐Ann Schmid
- Technische Universität BraunschweigDepartment of Energy Conversion, Institute of Physical and Theoretical ChemistryRebenring 3138106BraunschweigGermany
| | - Stefanie Tschierlei
- Technische Universität BraunschweigDepartment of Energy Conversion, Institute of Physical and Theoretical ChemistryRebenring 3138106BraunschweigGermany
| | - Sven Rau
- Institute of Inorganic Chemistry IUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | - Leticia González
- Institute of Theoretical ChemistryFaculty of ChemistryUniversity of ViennaWähringer Str. 171090ViennaAustria
- Vienna Research Platform Accelerating Photoreaction DiscoveryUniversity of ViennaWähringer Straße 171090ViennaAustria
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3
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Hernández‐Castillo D, Nau REP, Schmid M, Tschierlei S, Rau S, González L. Multiple Triplet Metal-Centered Jahn-Teller Isomers Determine Temperature-Dependent Luminescence Lifetimes in [Ru(bpy) 3 ] 2. Angew Chem Int Ed Engl 2023; 62:e202308803. [PMID: 37433755 PMCID: PMC10962642 DOI: 10.1002/anie.202308803] [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: 06/22/2023] [Revised: 07/11/2023] [Accepted: 07/11/2023] [Indexed: 07/13/2023]
Abstract
Understanding the factors that determine the luminescence lifetime of transition metal compounds is key for applications in photocatalysis and photodynamic therapy. Here we show that for[ Ru ( bpy ) 3 ] 2 + ${[{\rm{Ru}}({\rm{bpy}})_{\rm{3}} ]^{{\rm{2 + }}} }$ (bpy = 2,2'-bipyridine), the generally accepted idea that emission lifetimes can be controlled optimizing the energy barrier from the emissive triplet metal-to-ligand charge-transfer (3 MLCT) state to the thermally-activated triplet metal-centered (3 MC) state or the energy gap between both states is a misconception. Further, we demonstrate that considering a single relaxation pathway determined from the minimum that is lowest in energy leads to wrong temperature-dependent emission lifetimes predictions. Instead, we obtain excellent agreement with experimental temperature-dependent lifetimes when an extended kinetic model that includes all the pathways related to multiple Jahn-Teller isomers and their effective reaction barriers is employed. These concepts are essential to correctly design other luminescent transition metal complexes with tailored emission lifetimes based on theoretical predictions.
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Affiliation(s)
- David Hernández‐Castillo
- Institute of Theoretical ChemistryFaculty of ChemistryUniversity of ViennaWähringer Str. 171090ViennaAustria
- Doctoral School in Chemistry (DoSChem)University of ViennaWähringer Straße 421090ViennaAustria
| | - Roland E. P. Nau
- Institute of Inorganic Chemistry IUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | - Marie‐Ann Schmid
- Technische Universität BraunschweigDepartment of Energy Conversion, Institute of Physical and Theoretical ChemistryRebenring 3138106BraunschweigGermany
| | - Stefanie Tschierlei
- Technische Universität BraunschweigDepartment of Energy Conversion, Institute of Physical and Theoretical ChemistryRebenring 3138106BraunschweigGermany
| | - Sven Rau
- Institute of Inorganic Chemistry IUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | - Leticia González
- Institute of Theoretical ChemistryFaculty of ChemistryUniversity of ViennaWähringer Str. 171090ViennaAustria
- Vienna Research Platform Accelerating Photoreaction DiscoveryUniversity of ViennaWähringer Straße 171090ViennaAustria
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4
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Yin CW, Tsai MK, Chen YJ. Low-Temperature Observation of the Excited-State Decay of Ruthenium-(Mono-2,2':6',2″-Terpyridine) Ions with Innocent Ligands: DFT Modeling of an 3MLCT- 3MC Intersystem Crossing Pathway. ACS OMEGA 2023; 8:11623-11633. [PMID: 37008138 PMCID: PMC10061511 DOI: 10.1021/acsomega.3c01006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 02/28/2023] [Indexed: 06/19/2023]
Abstract
The synthesis, electrochemistry, and photophysical characterization of five 2,2':6',2″-terpyridine ruthenium complexes (Ru-tpy complexes) is reported. The electrochemical and photophysical behavior varied depending on the ligands, i.e., amine (NH3), acetonitrile (AN), and bis(pyrazolyl)methane (bpm), for this series of Ru-tpy complexes. The target [Ru(tpy)(AN)3]2+ and [Ru(tpy)(bpm)(AN)]2+ complexes were found to have low-emission quantum yields in low-temperature observations. To better understand this phenomenon, density functional theory (DFT) calculations were performed to simulate the singlet ground state (S0), Te, and metal-centered excited states (3MC) of these complexes. The calculated energy barriers between Te and the low-lying 3MC state for [Ru(tpy)(AN)3]2+ and [Ru(tpy)(bpm)(AN)]2+ provided clear evidence in support of their emitting state decay behavior. Developing a knowledge of the underlying photophysics of these Ru-tpy complexes will allow new complexes to be designed for use in photophysical and photochemical applications in the future.
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Affiliation(s)
- Chi-Wei Yin
- Department
of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| | - Ming-Kang Tsai
- Department
of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
- Department
of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan, ROC
| | - Yuan Jang Chen
- Department
of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
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5
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Chih YR, Lin YT, Yin CW, Chen YJ. High Intrinsic Phosphorescence Efficiency and Density Functional Theory Modeling of Ru(II)-Bipyridine Complexes with π-Aromatic-Rich Cyclometalated Ligands: Attributions of Spin-Orbit Coupling Perturbation and Efficient Configurational Mixing of Singlet Excited States. ACS OMEGA 2022; 7:48583-48599. [PMID: 36591186 PMCID: PMC9798779 DOI: 10.1021/acsomega.2c07276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 11/23/2022] [Indexed: 06/17/2023]
Abstract
A series of π-aromatic-rich cyclometalated ruthenium(II)-(2,2'-bipyridine) complexes ([Ru(bpy)2(πAr-CM)]+) in which πAr-CM is diphenylpyrazine or 1-phenylisoquinoline were prepared. The [Ru(bpy)2(πAr-CM)]+ complexes had remarkably high phosphorescence rate constants, k RAD(p), and the intrinsic phosphorescence efficiencies (ιem(p) = k RAD(p)/(νem(p))3) of these complexes were found to be twice the magnitudes of simply constructed cyclometalated ruthenium(II) complexes ([Ru(bpy)2(sc-CM)]+), where νem(p) is the phosphorescence frequency and sc-CM is 2-phenylpyridine, benzo[h]quinoline, or 2-phenylpyrimidine. Density functional theory (DFT) modeling of the [Ru(bpy)2(CM)]+ complexes indicated numerous singlet metal-to-ligand charge transfers for 1MLCT-(Ru-bpy) and 1MLCT-(Ru-CM), excited states in the low-energy absorption band and 1ππ*-(aromatic ligand) (1ππ*-LAr) excited states in the high-energy band. DFT modeling of these complexes also indicated phosphorescence-emitting state (Te) configurations with primary MLCT-(Ru-bpy) characteristics. The variation in ιem(p) for the spin-forbidden Te (3MLCT-(Ru-bpy)) excited state of the complex system that was examined in this study can be understood through the spin-orbit coupling (SOC)-mediated sum of intensity stealing (∑SOCM-IS) contribution from the primary intensity of the low-energy 1MLCT states and second-order intensity perturbation from the significant configuration between the low-energy 1MLCT and high-energy intense 1ππ*-LAr states. In addition, the observation of unusually high ιem(p) magnitudes for these [Ru(bpy)2(πAr-CM)]+ complexes can be attributed to the values for both intensity factors in the ∑SOCM-IS formalism being individually greater than those for [Ru(bpy)2(sc-CM)]+ ions.
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6
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Steinke SJ, Piechota EJ, Loftus LM, Turro C. Acetonitrile Ligand Photosubstitution in Ru(II) Complexes Directly from the 3MLCT State. J Am Chem Soc 2022; 144:20177-20182. [DOI: 10.1021/jacs.2c07209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sean J. Steinke
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio43210, United States
| | - Eric J. Piechota
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio43210, United States
| | - Lauren M. Loftus
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio43210, United States
| | - Claudia Turro
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio43210, United States
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7
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Synthesis, characterization, structural and photophysical properties of heteroleptic ruthenium complexes containing 2-(1H-benzo[d]imidazol-2-yl)quinoline ligand towards electrocatalytic CO2 reduction. J CHEM SCI 2022. [DOI: 10.1007/s12039-022-02063-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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8
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Rational design of mitochondria targeted thiabendazole-based Ir(III) biscyclometalated complexes for a multimodal photodynamic therapy of cancer. J Inorg Biochem 2022; 231:111790. [DOI: 10.1016/j.jinorgbio.2022.111790] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 02/25/2022] [Accepted: 03/07/2022] [Indexed: 12/13/2022]
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9
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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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10
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Motimani NM, Ngubane S, Smith GS. Polynuclear heteroleptic ruthenium(II) photoredox catalysts: Evaluation in blue-light-mediated, regioselective thiol-ene reactions. Polyhedron 2022. [DOI: 10.1016/j.poly.2021.115616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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11
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Qu F, Lamb RW, Cameron CG, Park S, Oladipupo O, Gray JL, Xu Y, Cole HD, Bonizzoni M, Kim Y, McFarland SA, Webster CE, Papish ET. Singlet Oxygen Formation vs Photodissociation for Light-Responsive Protic Ruthenium Anticancer Compounds: The Oxygenated Substituent Determines Which Pathway Dominates. Inorg Chem 2021; 60:2138-2148. [PMID: 33534562 DOI: 10.1021/acs.inorgchem.0c02027] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Ruthenium complexes bearing protic diimine ligands are cytotoxic to certain cancer cells upon irradiation with blue light. Previously reported complexes of the type [(N,N)2Ru(6,6'-dhbp)]Cl2 with 6,6'-dhbp = 6,6'-dihydroxybipyridine and N,N = 2,2'-bipyridine (bipy) (1A), 1,10-phenanthroline (phen) (2A), and 2,3-dihydro-[1,4]dioxino[2,3-f][1,10]phenanthroline (dop) (3A) show EC50 values as low as 4 μM (for 3A) vs breast cancer cells upon blue light irradiation ( Inorg. Chem. 2017, 56, 7519). Herein, subscript A denotes the acidic form of the complex bearing OH groups, and B denotes the basic form bearing O- groups. This photocytotoxicity was originally attributed to photodissociation, but recent results suggest that singlet oxygen formation is a more plausible cause of photocytotoxicity. In particular, bulky methoxy substituents enhance photodissociation but these complexes are nontoxic ( Dalton Trans 2018, 47, 15685). Cellular studies are presented herein that show the formation of reactive oxygen species (ROS) and apoptosis indicators upon treatment of cells with complex 3A and blue light. Singlet oxygen sensor green (SOSG) shows the formation of 1O2 in cell culture for cells treated with 3A and blue light. At physiological pH, complexes 1A-3A are deprotonated to form 1B-3B in situ. Quantum yields for 1O2 (ϕΔ) are 0.87 and 0.48 for 2B and 3B, respectively, and these are an order of magnitude higher than the quantum yields for 2A and 3A. The values for ϕΔ show an increase with 6,6'-dhbp derived substituents as follows: OMe < OH < O-. TD-DFT studies show that the presence of a low lying triplet metal-centered (3MC) state favors photodissociation and disfavors 1O2 formation for 2A and 3A (OH groups). However, upon deprotonation (O- groups), the 3MLCT state is accessible and can readily lead to 1O2 formation, but the dissociative 3MC state is energetically inaccessible. The changes to the energy of the 3MLCT state upon deprotonation have been confirmed by steady state luminescence experiments on 1A-3A and their basic analogs, 1B-3B. This energy landscape favors 1O2 formation for 2B and 3B and leads to enhanced toxicity for these complexes under physiological conditions. The ability to convert readily from OH to O- groups allowed us to investigate an electronic change that is not accompanied by steric changes in this fundamental study.
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Affiliation(s)
- Fengrui Qu
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Robert W Lamb
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Colin G Cameron
- Department of Chemistry and Biochemistry, University of Texas Arlington, Arlington, Texas 76019, United States
| | - Seungjo Park
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Olaitan Oladipupo
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Jessica L Gray
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Yifei Xu
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Houston D Cole
- Department of Chemistry and Biochemistry, University of Texas Arlington, Arlington, Texas 76019, United States
| | - Marco Bonizzoni
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Yonghyun Kim
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Sherri A McFarland
- Department of Chemistry and Biochemistry, University of Texas Arlington, Arlington, Texas 76019, United States
| | - Charles Edwin Webster
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Elizabeth T Papish
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
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12
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Bevernaegie R, Wehlin SAM, Elias B, Troian‐Gautier L. A Roadmap Towards Visible Light Mediated Electron Transfer Chemistry with Iridium(III) Complexes. CHEMPHOTOCHEM 2021. [DOI: 10.1002/cptc.202000255] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Robin Bevernaegie
- Laboratoire de Chimie Organique CP160/06 Université libre de Bruxelles 50 avenue F. R. Roosevelt 1050 Brussels Belgium
- Institut de la Matière Condensée et des Nanosciences (IMCN) Molecular Chemistry, Materials and Catalysis (MOST) Université catholique de Louvain (UCLouvain) Place Louis Pasteur 1 box L4.01.02 1348 Louvain-la-Neuve Belgium
| | - Sara A. M. Wehlin
- Laboratoire de Chimie Organique CP160/06 Université libre de Bruxelles 50 avenue F. R. Roosevelt 1050 Brussels Belgium
| | - Benjamin Elias
- Institut de la Matière Condensée et des Nanosciences (IMCN) Molecular Chemistry, Materials and Catalysis (MOST) Université catholique de Louvain (UCLouvain) Place Louis Pasteur 1 box L4.01.02 1348 Louvain-la-Neuve Belgium
| | - Ludovic Troian‐Gautier
- Laboratoire de Chimie Organique CP160/06 Université libre de Bruxelles 50 avenue F. R. Roosevelt 1050 Brussels Belgium
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13
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Cerfontaine S, Troian-Gautier L, Duez Q, Cornil J, Gerbaux P, Elias B. MLCT Excited-State Behavior of Trinuclear Ruthenium(II) 2,2'-Bipyridine Complexes. Inorg Chem 2021; 60:366-379. [PMID: 33351615 DOI: 10.1021/acs.inorgchem.0c03004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Four trinuclear ruthenium(II) polypyridyl complexes were synthesized, and a detailed investigation of their excited-state properties was performed. The tritopic sexi-pyridine bridging ligands were obtained via para or meta substitution of a central 2,2'-bipyridine fragment. A para connection between the 2,2'-bipyridine chelating moieties of the bridging ligand led to a red-shifted MLCT absorption band in the visible part of the spectra, whereas the meta connection induced a broadening of the LC transitions in the UV region. A convergent energy transfer from the two peripheral metal centers to the central Ru(II) moiety was observed for all trinuclear complexes. These complexes were in thermal equilibrium with an upper-lying 3MLCT excited state over the investigated range of temperatures. For all complexes, deactivation via the 3MC excited state was absent at room temperature. Importantly, the connection in the para position for both central and peripheral 2,2'-bipyridines of the bridging ligand resulted in a trinuclear complex (Tpp) that absorbed more visible light, had a longer-lived excited state, and had a higher photoluminescence quantum yield than the parent [Ru(bpy)3]2+, despite its red-shifted photoluminescence. This behavior was attributed to the presence of a highly delocalized excited state for Tpp.
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Affiliation(s)
- Simon Cerfontaine
- 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
- Laboratoire de Chimie Organique, Université libre de Bruxelles (ULB), CP 160/06, 50 avenue F.D. Roosevelt, 1050 Brussels, Belgium.,Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Quentin Duez
- Organic Synthesis and Mass Spectrometry Laboratory, University of Mons - UMONS, 23 Place du Parc, B-7000 Mons, Belgium.,Laboratory for Chemistry of Novel Materials, Center of Innovation and Research in Materials and Polymers (CIRMAP) - University of Mons (UMONS), Place du Parc 23, B-7000 Mons, Belgium
| | - Jérôme Cornil
- Laboratory for Chemistry of Novel Materials, Center of Innovation and Research in Materials and Polymers (CIRMAP) - University of Mons (UMONS), Place du Parc 23, B-7000 Mons, Belgium
| | - Pascal Gerbaux
- Organic Synthesis and Mass Spectrometry Laboratory, University of Mons - UMONS, 23 Place du Parc, B-7000 Mons, Belgium
| | - 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
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14
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Hua W, Xu G, Zhao J, Wang Z, Lu J, Sun W, Gou S. DNA‐Targeting Ru
II
‐Polypyridyl Complex with a Long‐Lived Intraligand Excited State as a Potential Photodynamic Therapy Agent. Chemistry 2020; 26:17495-17503. [DOI: 10.1002/chem.202003031] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/28/2020] [Indexed: 12/18/2022]
Affiliation(s)
- Wuyang Hua
- Jiangsu Province Hi-Tech Key Laboratory for Biomedical Research and Pharmaceutical Research Center School of Chemistry and Chemical, Engineering Southeast University Nanjing 211189 P.R. China
| | - Gang Xu
- Jiangsu Province Hi-Tech Key Laboratory for Biomedical Research and Pharmaceutical Research Center School of Chemistry and Chemical, Engineering Southeast University Nanjing 211189 P.R. China
| | - Jian Zhao
- Jiangsu Province Hi-Tech Key Laboratory for Biomedical Research and Pharmaceutical Research Center School of Chemistry and Chemical, Engineering Southeast University Nanjing 211189 P.R. China
| | - Z. Wang
- Jiangsu Province Hi-Tech Key Laboratory for Biomedical Research and Pharmaceutical Research Center School of Chemistry and Chemical, Engineering Southeast University Nanjing 211189 P.R. China
| | - Jiapeng Lu
- Department of Chemistry and Biochemistry North Dakota State University Fargo North Dakota 58108-6050 USA
| | - Wenfang Sun
- Department of Chemistry and Biochemistry North Dakota State University Fargo North Dakota 58108-6050 USA
| | - Shaohua Gou
- Jiangsu Province Hi-Tech Key Laboratory for Biomedical Research and Pharmaceutical Research Center School of Chemistry and Chemical, Engineering Southeast University Nanjing 211189 P.R. China
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15
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Zhang Y, Leary DC, Belldina AM, Petersen JL, Milsmann C. Effects of Ligand Substitution on the Optical and Electrochemical Properties of (Pyridinedipyrrolide)zirconium Photosensitizers. Inorg Chem 2020; 59:14716-14730. [PMID: 32975946 DOI: 10.1021/acs.inorgchem.0c02343] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of seven bis(pyridinedipyrrolide)zirconium complexes, Zr(R1PDPR2)2, where [R1PDPR2]2- is the doubly deprotonated form of [2,6-bis(5-R1-3-R2-1H-pyrrol-2-yl)pyridine], were prepared and characterized in solution by NMR, UV/vis absorption, and emission spectroscopy and cyclic voltammetry. The molecular structures were determined by single-crystal X-ray crystallography. All complexes exhibit remarkably long emission lifetimes (τ = 190-576 μs) with high quantum efficiencies (ΦPL = 0.10-0.38) upon excitation with visible light in a benzene solution. The substituents on the pyrrolide rings were shown to have significant effects on the photoluminescence and electrochemical properties of these compounds. The R2 substituents (R2 = H, Me, Ph, or C6F5) show only limited effects on the absorption and emission profiles of the complexes but allow systematic tuning of the ground- and excited-state redox potentials over a range of almost 600 mV. The R1 substituents (R1 = H, Me, Ph, or 2,4,6-Me3Ph) influence both the optical and electrochemical properties through electronic effects. Additionally, the R1 substituents have profound consequences for the structural flexibility and overall stability of the compounds. Distortions of the Zr(PDP)2 core from idealized D2d symmetry in the solid state can be traced to the steric profiles of the R1 substituents and correlate with the observed Stokes shifts for each compound. The complex with the smallest ligand system, Zr(HPDPH)2, coordinates two additional solvent molecules in a tetrahydrofuran (THF) solution, which allowed the isolation of photoluminescent, eight-coordinate Zr(HPDPH)2(THF)2. The photoredox catalytic dehalogenation of aryl iodides and aryl chlorides using the most reducing derivative, Zr(MePDPMe)2, highlights the potential of Zr(PDP)2 photosensitizers to promote challenging reductive transformations under mild conditions upon excitation with green light.
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Affiliation(s)
- Yu Zhang
- C. Eugene Bennett Department of Chemistry, West Virginia University (WVU), 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Dylan C Leary
- C. Eugene Bennett Department of Chemistry, West Virginia University (WVU), 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Anne M Belldina
- C. Eugene Bennett Department of Chemistry, West Virginia University (WVU), 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Jeffrey L Petersen
- C. Eugene Bennett Department of Chemistry, West Virginia University (WVU), 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Carsten Milsmann
- C. Eugene Bennett Department of Chemistry, West Virginia University (WVU), 100 Prospect Street, Morgantown, West Virginia 26506, United States
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16
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Yagüe C, Echevarría I, Vaquero M, Fidalgo J, Carbayo A, Jalón FA, Lima JC, Moro AJ, Manzano BR, Espino G. Non-emissive Ru II Polypyridyl Complexes as Efficient and Selective Photosensitizers for the Photooxidation of Benzylamines. Chemistry 2020; 26:12219-12232. [PMID: 32301532 DOI: 10.1002/chem.202001460] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/16/2020] [Indexed: 11/07/2022]
Abstract
Five new RuII polypyridyl complexes bearing N-(arylsulfonyl)-8-amidoquinolate ligands and three of their biscyclometalated IrIII congeners have been prepared and employed as photocatalysts (PCs) in the photooxidation of benzylamines with O2 . In particular, the new RuII complexes do not exhibit photoluminescence, rather they harvest visible light efficiently and are very stable in solution under irradiation with blue light. Their non-emissive behavior has been related to the low electrochemical energy gaps and rationalized on the basis of theoretical calculations (DFT analysis) that predict low S0 ←T1 energy values. Moreover, the RuII complexes, despite being non-emissive, display excellent activities in the selective photocatalytic transformation of benzylamines into the corresponding imines. The presence of an electron-withdrawing group (-CF3) on the arene ring of the N-(arylsulfonyl)-8-amidoquinolate ligand improves the photocatalytic activity of the corresponding photocatalyst. Furthermore, all the experimental evidence, including transient absorption spectroscopy measurements suggest that singlet oxygen is the actual oxidant. The IrIII analogues are considerably more photosensitive and consequently less efficient photosensitizers (PSs).
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Affiliation(s)
- Cristina Yagüe
- Universidad de Burgos, Departamento de Química, Facultad de Ciencias, Plaza Misael Bañuelos s/n, 09001, Burgos, Spain
| | - Igor Echevarría
- Universidad de Burgos, Departamento de Química, Facultad de Ciencias, Plaza Misael Bañuelos s/n, 09001, Burgos, Spain
| | - Mónica Vaquero
- Universidad de Burgos, Departamento de Química, Facultad de Ciencias, Plaza Misael Bañuelos s/n, 09001, Burgos, Spain
| | - Jairo Fidalgo
- Universidad de Burgos, Departamento de Química, Facultad de Ciencias, Plaza Misael Bañuelos s/n, 09001, Burgos, Spain
| | - Arancha Carbayo
- Universidad de Burgos, Departamento de Química, Facultad de Ciencias, Plaza Misael Bañuelos s/n, 09001, Burgos, Spain
| | - Félix A Jalón
- Universidad de Castilla-La Mancha, Departamento de Química Inorgánica, Orgánica y Bioquímica, Facultad de Químicas, Avda. Camilo J. Cela 10, 13071, Ciudad Real, Spain
| | - João C Lima
- Universidade NOVA de Lisboa, LAQV-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, 2829-516, Caparica, Portugal
| | - Artur J Moro
- Universidade NOVA de Lisboa, LAQV-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, 2829-516, Caparica, Portugal
| | - Blanca R Manzano
- Universidad de Castilla-La Mancha, Departamento de Química Inorgánica, Orgánica y Bioquímica, Facultad de Químicas, Avda. Camilo J. Cela 10, 13071, Ciudad Real, Spain
| | - Gustavo Espino
- Universidad de Burgos, Departamento de Química, Facultad de Ciencias, Plaza Misael Bañuelos s/n, 09001, Burgos, Spain
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17
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Wehlin SAM, Troian-Gautier L, Maurer AB, Brennaman MK, Meyer GJ. Photophysical characterization of new osmium (II) photocatalysts for hydrohalic acid splitting. J Chem Phys 2020; 153:054307. [DOI: 10.1063/5.0014269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Sara A. M. Wehlin
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA
| | - Ludovic Troian-Gautier
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA
- Laboratoire de Chimie Organique, Université libre de Bruxelles (ULB), CP 160/06, 50 Avenue F.D. Roosevelt, B-1050 Brussels, Belgium
| | - Andrew B. Maurer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA
| | - M. Kyle Brennaman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA
| | - Gerald J. Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA
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18
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Bevernaegie R, Wehlin SAM, Piechota EJ, Abraham M, Philouze C, Meyer GJ, Elias B, Troian-Gautier L. Improved Visible Light Absorption of Potent Iridium(III) Photo-oxidants for Excited-State Electron Transfer Chemistry. J Am Chem Soc 2020; 142:2732-2737. [DOI: 10.1021/jacs.9b12108] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Robin Bevernaegie
- UCLouvain, Institut de la Matière Condensée et des Nanosciences (IMCN), Molecular Chemistry, Materials and Catalysis (MOST), Place Louis Pasteur 1, box L4.01.02, B-1348 Louvain-la-Neuve, Belgium
| | - Sara A. M. Wehlin
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Eric J. Piechota
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Michael Abraham
- UCLouvain, Institut de la Matière Condensée et des Nanosciences (IMCN), Molecular Chemistry, Materials and Catalysis (MOST), Place Louis Pasteur 1, box L4.01.02, B-1348 Louvain-la-Neuve, Belgium
| | - Christian Philouze
- Département de Chimie Moléculaire, Université Grenoble-Alpes (UGA), UMR CNRS 5250, CS 40700, 38058 Grenoble, France
| | - Gerald J. Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Benjamin Elias
- UCLouvain, Institut de la Matière Condensée et des Nanosciences (IMCN), Molecular Chemistry, Materials and Catalysis (MOST), Place Louis Pasteur 1, box L4.01.02, B-1348 Louvain-la-Neuve, Belgium
| | - Ludovic Troian-Gautier
- 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, B-1050 Brussels, Belgium
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19
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Cerfontaine S, Troian-Gautier L, Wehlin SAM, Loiseau F, Cauët E, Elias B. Tuning the excited-state deactivation pathways of dinuclear ruthenium(ii) 2,2′-bipyridine complexes through bridging ligand design. Dalton Trans 2020; 49:8096-8106. [DOI: 10.1039/d0dt01216e] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A detailed photophysical study of binuclear complexes was performed using steady-state and time-resolved photoluminescence measurements at variable temperature. The results were compared with the prototypical [Ru(bpy)3]2+.
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Affiliation(s)
- Simon Cerfontaine
- Université catholique de Louvain (UCLouvain)
- Institut de la Matière Condensée et des Nanosciences (IMCN)
- Molecular Chemistry
- Materials and Catalysis (MOST)
- 1348 Louvain-la-Neuve
| | - Ludovic Troian-Gautier
- Laboratoire de Chimie Organique
- Université libre de Bruxelles (ULB)
- 1050 Brussels
- Belgium
- Department of Chemistry
| | - Sara A. M. Wehlin
- Department of Chemistry
- University of North Carolina at Chapel Hill
- Chapel Hill
- USA
| | - Frédérique Loiseau
- Département de Chimie Moléculaire
- Univ. Grenoble-Alpes (UGA)
- 38058 Grenoble
- France
| | - Emilie Cauët
- Spectroscopy
- Quantum Chemistry and Atmospheric Remote Sensing (CP 160/09)
- Université libre de Bruxelles
- B-1050 Brussels
- Belgium
| | - Benjamin Elias
- Université catholique de Louvain (UCLouvain)
- Institut de la Matière Condensée et des Nanosciences (IMCN)
- Molecular Chemistry
- Materials and Catalysis (MOST)
- 1348 Louvain-la-Neuve
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20
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Asahara M, Kurimoto H, Nakamizu M, Hattori S, Shinozaki K. H/D solvent isotope effects on the photoracemization reaction of enantiomeric the tris(2,2′-bipyridine)ruthenium(ii) complex and its analogues. Phys Chem Chem Phys 2020; 22:6361-6369. [DOI: 10.1039/c9cp06758b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This work assessed solvent isotope effects on the photoracemization rate and emission lifetime for [Ru(bpy)3]2+ (bpy = 2,2′-bipyridine) in water.
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Affiliation(s)
- Masahiro Asahara
- Department of Materials Science
- Graduate School of Nanobioscience
- Yokohama City University
- Kanazawa-ku
- Japan
| | - Haruhiko Kurimoto
- Department of Materials Science
- Graduate School of Nanobioscience
- Yokohama City University
- Kanazawa-ku
- Japan
| | - Masato Nakamizu
- Department of Materials Science
- Graduate School of Nanobioscience
- Yokohama City University
- Kanazawa-ku
- Japan
| | - Shingo Hattori
- Department of Materials Science
- Graduate School of Nanobioscience
- Yokohama City University
- Kanazawa-ku
- Japan
| | - Kazuteru Shinozaki
- Department of Materials Science
- Graduate School of Nanobioscience
- Yokohama City University
- Kanazawa-ku
- Japan
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21
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Zhang XZ, Cheng CC, Chih YR, Lin YT, Chen HY, Chen YJ, Endicott JF. Low-Temperature Spectra and Density Functional Theory Modeling of Ru(II)-Bipyridine Complexes with Cyclometalated Ancillary Ligands: The Excited State Spin-Orbit Coupling Origin of Variations in Emission Efficiencies. J Phys Chem A 2019; 123:9431-9449. [PMID: 31557033 DOI: 10.1021/acs.jpca.9b05695] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The 77 K emission spectra of cyclometalated ruthenium(II)-2,2'-bipyridine (CM-Ru-bpy) chromophores are very similar to those of related Ru-bpy complexes with am(m)ine or diimmine ancillary ligands, and density functional theory (DFT) modeling confirms that the lowest energy triplet metal to ligand charge transfer (3MLCT) excited states of CM-Ru-bpy and related Ru-bpy complexes have very similar electronic configurations. However, the phosphorescence decay efficiencies of CM-Ru-bpy excited states are about twice those of the conventional Ru-bpy analogues. In contrast to the similar 3MLCT excited state electronic configurations of the two classes of complexes, the CM-Ru-bpy chromophores have much broader visible region MLCT absorptions resulting from several overlapping transitions, even at 87 K. The emitting excited-state emission efficiencies depend on spin-orbit coupling (SOC) mediated intensity stealing from singlet excited states, and this work explores the relationship between the phosphorescence efficiency and visible region absorption spectra of Ru-bpy 3MLCT excited states in the weak SOC limit. The intrinsic 3MLCT emission efficiency, ιem, depends on mixing with singlet excited states whose RuIII-dπ-orbital angular momenta differ from that of the emitting state. DFT modeling of the 1MLCT excited-state electronic configurations that contribute significantly to the lowest energy absorption bands have RuIII-dπ orbitals that differ from those of their emitting 3MLCT excited states. This leads to a very close relationship between ιem and the lowest energy MLCT band absorptivities in Ru-bpy chromophores. Thus, the larger number of 1MLCT transitions that contribute to the lowest energy absorption bands accounts for the enhanced phosphorescence efficiency of Ru-bpy complexes with cyclometalated ancillary ligands.
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Affiliation(s)
- Xiu Zhu Zhang
- Department of Chemistry , Fu-Jen Catholic University , New Taipei City 24205 , Taiwan , ROC
| | - Ching Chia Cheng
- Department of Chemistry , Fu-Jen Catholic University , New Taipei City 24205 , Taiwan , ROC
| | - Yu Ru Chih
- Department of Chemistry , Fu-Jen Catholic University , New Taipei City 24205 , Taiwan , ROC
| | - Yu-Ting Lin
- Department of Chemistry , Fu-Jen Catholic University , New Taipei City 24205 , Taiwan , ROC
| | - Hsing-Yin Chen
- Department of Medicinal and Applied Chemistry , Kaohsiung Medical University , Kaohsiung 80708 , Taiwan , ROC
| | - Yuan Jang Chen
- Department of Chemistry , Fu-Jen Catholic University , New Taipei City 24205 , Taiwan , ROC
| | - John F Endicott
- Department of Chemistry , Wayne State University , Detroit , Michigan 48202 , United States
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22
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McCain J, Colón KL, Barrett PC, Monro SMA, Sainuddin T, Roque Iii J, Pinto M, Yin H, Cameron CG, McFarland SA. Photophysical Properties and Photobiological Activities of Ruthenium(II) Complexes Bearing π-Expansive Cyclometalating Ligands with Thienyl Groups. Inorg Chem 2019; 58:10778-10790. [PMID: 31386351 DOI: 10.1021/acs.inorgchem.9b01044] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A new family of cyclometalated ruthenium(II) complexes [Ru(N^N)2(C^N)]+ derived from the π-extended benzo[h]imidazo[4,5-f]quinolone ligand appended with thienyl groups (n = 1-4, compounds 1-4) was prepared and its members were characterized for their chemical, photophysical, and photobiological properties. The lipophilicities of 1-4, determined as octanol-water partition coefficients (log Po/w), were positive and increased with the number of thienyl units. The absorption and emission bands of the C^N compounds were red-shifted by up to 200 nm relative to the analogous Ru(II) diimine systems. All of the complexes exhibited dual emission with the intraligand fluorescence (1IL, C^N-based) shifting to lower energies with increasing n and the metal-to-ligand charge transfer phosphorescence (3MLCT, N^N-based) remaining unchanged. Compounds 1-3 exhibited excited state absorption (ESA) profiles consistent with lowest-lying 3MLCT states when probed by nanosecond transient absorption (TA) spectroscopy with 532 nm excitation and had contributions from 1IL(C^N) states with 355 nm excitation. These assignments were supported by the lifetimes observed (<10 ns for the 1IL states and around 20 ns for the 3MLCT states) as well as a noticeable ESA for 3 with 355 nm excitation that did not occur with 532 nm excitation. Compound 4 was the only member of the family with two 3MLCT emissive lifetimes (15, 110 ns), and the TA spectra collected with both 355 and 532 nm excitation was assigned to the 3IL state, which was corroborated by its 4-6 μs lifetime. The ESA for 4 had a rise time of approximately 10 ns and an initial decay of 110 ns, which suggests a possible 3MLCT-3IL excited state equilibrium that results in delayed emission from the 3MLCT state. Compound 4 was nontoxic toward human skin melanoma cells (SKMEL28) in the dark (EC50 = >300 μM); 1-3 were cytotoxic and yielded EC50 values between 1 and 20 μM. The photocytotoxicites with visible light ranged from 87 nM with a phototherapeutic index (PI) of 13 for 1 to approximately 1 μM (PI = >267) for 4. With red light, EC50 values varied from 270 nM (PI = 21) for 3 to 12 μM for 4 (PI = >25). The larger PIs for 4, especially with visible light, were attributed to the much lower dark cytotoxicity for this compound. Because the dark cytotoxicity contributes substantially to the observed photocytotoxicity for 1-3, it was not possible to assess whether the 3IL state of 4 led to a much more potent phototoxic mechanism in the absence of dark toxicity. There was no stark contrast in cellular uptake and accumulation by laser scanning confocal and differential interference contrast microscopy to explain the large differences in dark toxicities between 1-3 and 4. Nevertheless, the study highlights a new family of Ru(II) C^N complexes where π-conjugation beyond a certain point results in low dark cytotoxicity with high photocytotoxicity, opposing the notion that cyclometalated Ru(II) systems are too toxic to be phototherapeutic agents.
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Affiliation(s)
- Julia McCain
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia B4P 2R6 , Canada
| | - Katsuya L Colón
- Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro , North Carolina 27402 , United States
| | - Patrick C Barrett
- Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro , North Carolina 27402 , United States
| | - Susan M A Monro
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia B4P 2R6 , Canada
| | - Tariq Sainuddin
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia B4P 2R6 , Canada
| | - John Roque Iii
- Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro , North Carolina 27402 , United States
| | - Mitch Pinto
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia B4P 2R6 , Canada
| | - Huimin Yin
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia B4P 2R6 , Canada
| | - Colin G Cameron
- Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro , North Carolina 27402 , United States
| | - Sherri A McFarland
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia B4P 2R6 , Canada.,Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro , North Carolina 27402 , United States
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23
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Steube J, Burkhardt L, Päpcke A, Moll J, Zimmer P, Schoch R, Wölper C, Heinze K, Lochbrunner S, Bauer M. Excited‐State Kinetics of an Air‐Stable Cyclometalated Iron(II) Complex. Chemistry 2019; 25:11826-11830. [DOI: 10.1002/chem.201902488] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Jakob Steube
- Institute of Inorganic Chemistry and Center for Sustainable, Systems Design (CSSD)University of Paderborn Warburger Straße 100 33098 Paderborn Germany
| | - Lukas Burkhardt
- Institute of Inorganic Chemistry and Center for Sustainable, Systems Design (CSSD)University of Paderborn Warburger Straße 100 33098 Paderborn Germany
| | - Ayla Päpcke
- Institute of Physics and Department of Life, Light and MatterUniversity of Rostock 18051 Rostock Germany
| | - Johannes Moll
- Institute of Inorganic Chemistry and Analytical ChemistryJohannes Gutenberg University Duesbergweg 10–14 55128 Mainz Germany
| | - Peter Zimmer
- Institute of Inorganic Chemistry and Center for Sustainable, Systems Design (CSSD)University of Paderborn Warburger Straße 100 33098 Paderborn Germany
| | - Roland Schoch
- Institute of Inorganic Chemistry and Center for Sustainable, Systems Design (CSSD)University of Paderborn Warburger Straße 100 33098 Paderborn Germany
| | - Christoph Wölper
- Institute for Inorganic Chemistry and Center for Nanointegration, Duisburg-Essen (Cenide)University of Duisburg-Essen Universitätsstraße 5-7 45117 Essen Germany
| | - Katja Heinze
- Institute of Inorganic Chemistry and Analytical ChemistryJohannes Gutenberg University Duesbergweg 10–14 55128 Mainz Germany
| | - Stefan Lochbrunner
- Institute of Physics and Department of Life, Light and MatterUniversity of Rostock 18051 Rostock Germany
| | - Matthias Bauer
- Institute of Inorganic Chemistry and Center for Sustainable, Systems Design (CSSD)University of Paderborn Warburger Straße 100 33098 Paderborn Germany
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24
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Troian-Gautier L, Turlington MD, Wehlin SAM, Maurer AB, Brady MD, Swords WB, Meyer GJ. Halide Photoredox Chemistry. Chem Rev 2019; 119:4628-4683. [PMID: 30854847 DOI: 10.1021/acs.chemrev.8b00732] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Halide photoredox chemistry is of both practical and fundamental interest. Practical applications have largely focused on solar energy conversion with hydrogen gas, through HX splitting, and electrical power generation, in regenerative photoelectrochemical and photovoltaic cells. On a more fundamental level, halide photoredox chemistry provides a unique means to generate and characterize one electron transfer chemistry that is intimately coupled with X-X bond-breaking and -forming reactivity. This review aims to deliver a background on the solution chemistry of I, Br, and Cl that enables readers to understand and utilize the most recent advances in halide photoredox chemistry research. These include reactions initiated through outer-sphere, halide-to-metal, and metal-to-ligand charge-transfer excited states. Kosower's salt, 1-methylpyridinium iodide, provides an early outer-sphere charge-transfer excited state that reports on solvent polarity. A plethora of new inner-sphere complexes based on transition and main group metal halide complexes that show promise for HX splitting are described. Long-lived charge-transfer excited states that undergo redox reactions with one or more halogen species are detailed. The review concludes with some key goals for future research that promise to direct the field of halide photoredox chemistry to even greater heights.
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Affiliation(s)
- Ludovic Troian-Gautier
- Department of Chemistry , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Michael D Turlington
- Department of Chemistry , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Sara A M Wehlin
- Department of Chemistry , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Andrew B Maurer
- Department of Chemistry , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Matthew D Brady
- Department of Chemistry , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Wesley B Swords
- Department of Chemistry , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Gerald J Meyer
- Department of Chemistry , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
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25
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Abstract
Iodide redox chemistry is intimately coupled with the formation and breaking of chemical bonds that are relevant to emerging solar energy technologies. In this Account, recent advances in dye-sensitized iodide oxidation chemistry in organic solutions are described. Here RuII sensitizers with high cationic charge, tuned reduction potentials, and specific iodide receptor site(s) are shown to self-assemble in organic solvents and yield structures that rapidly oxidize iodide and generate I-I bonds when illuminated with visible light. These studies provided new insights into the fascinating behavior of our most polarizable and easily oxidized monatomic anion. Sensitized iodide photo-oxidation in CH3CN solutions consists of two mechanistic steps. In the first step, an excited-state sensitizer oxidizes iodide (I-) to an iodine atom (I•) through diffusional encounters. The second step involves the reaction of I• with I- to form the I-I bond of diiodide, I2•-. The overall reaction converts a green photon into about 1.64 eV of free energy in the form of I2•- and the reduced sensitizer. The free energy is only transiently available, as back-electron transfer to yield ground-state products is quantitative. Interestingly, when the free energy change is near zero, iodide photo-oxidation occurs rapidly with rate constants near the diffusion limit, i.e., >1010 M-1 s-1. Such rapid reactivity is in line with anecdotal knowledge that iodide is an outstanding electron donor and is indicative of adiabatic electron transfer through an inner-sphere mechanism. In low-dielectric-constant solvents, dicationic RuII sensitizers were found to form tight ion pairs with iodide. Diimine ligands with additional cationic charge, or "binding pockets" that recognize halides, have been utilized to position one or more halides at specific locations about the sensitizer before light absorption. Diverse photochemical reactions observed with these supramolecular assemblies range from the photorelease of halides to the formation of I-I bonds where both iodides present in the ground-state assembly react. Natural population analysis through density functional theory calculations accurately predicts the site(s) of iodide ion-pairing and provides information on the associated free energy change. The ability to direct light-driven bond formation in these ionic assemblies is extended to chloride and bromide ions. The structure-property relationships identified, and those that continue to emerge, may one day allow for the rational design of molecules and materials that drive desired halide transformations when illuminated with light.
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Affiliation(s)
- Ludovic Troian-Gautier
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Wesley B. Swords
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Gerald J. Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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Troian-Gautier L, Wehlin SAM, Meyer GJ. Photophysical Properties of Tetracationic Ruthenium Complexes and Their Ter-Ionic Assemblies with Chloride. Inorg Chem 2018; 57:12232-12244. [DOI: 10.1021/acs.inorgchem.8b01921] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ludovic Troian-Gautier
- Department of Chemistry, University of North Carolina at Chapel Hill, Murray Hall 2202B, Chapel Hill, North Carolina 27599-3290, United States
| | - Sara A. M. Wehlin
- Department of Chemistry, University of North Carolina at Chapel Hill, Murray Hall 2202B, Chapel Hill, North Carolina 27599-3290, United States
| | - Gerald J. Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Murray Hall 2202B, Chapel Hill, North Carolina 27599-3290, United States
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Ghosh G, Colón KL, Fuller A, Sainuddin T, Bradner E, McCain J, Monro SMA, Yin H, Hetu MW, Cameron CG, McFarland SA. Cyclometalated Ruthenium(II) Complexes Derived from α-Oligothiophenes as Highly Selective Cytotoxic or Photocytotoxic Agents. Inorg Chem 2018; 57:7694-7712. [PMID: 29927243 DOI: 10.1021/acs.inorgchem.8b00689] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photophysical and photobiological properties of a new class of cyclometalated ruthenium(II) compounds incorporating π-extended benzo[ h]imidazo[4,5- f]quinoline (IBQ) cyclometalating ligands (C^N) bearing thienyl rings ( n = 1-4, compounds 1-4) were investigated. Their octanol-water partition coefficients (log Po/w) were positive and increased with n. Their absorption and emission energies were red-shifted substantially compared to the analogous Ru(II) diimine (N^N) complexes. They displayed C^N-based intraligand (IL) fluorescence and triplet excited-state absorption that shifted to longer wavelengths with increasing n and N^N-based metal-to-ligand charge transfer (MLCT) phosphorescence that was independent of n. Their photoluminescence lifetimes (τem) ranged from 4-10 ns for 1IL states and 12-18 ns for 3MLCT states. Transient absorption lifetimes (τTA) were 5-8 μs with 355 nm excitation, ascribed to 3IL states that became inaccessible for 1-3 with 532 nm excitation (1-3, τTA = 16-17 ns); the 3IL of 4 only was accessible by lower energy excitation, τTA = 3.8 μs. Complex 4 was nontoxic (EC50 > 300 μM) to SK-MEL-28 melanoma cells and CCD1064-Sk normal skin fibroblasts in the dark, while 3 was selectively cytotoxic to melanoma (EC50= 5.1 μM) only. Compounds 1 and 2 were selective for melanoma cells in the dark, with submicromolar potencies (EC50 = 350-500 nM) and selectivity factors (SFs) around 50. The photocytotoxicities of compounds 1-4 toward melanoma cells were similar, but only compounds 3 and 4 displayed significant phototherapeutic indices (PIs; 3, 43; 4, >1100). The larger cytotoxicities for compounds 1 and 2 were attributed to increased cellular uptake and nuclear accumulation, and possibly related to the DNA-aggregating properties of all four compounds as demonstrated by cell-free gel mobility-shift assays. Together, these results demonstrate a new class of thiophene-containing Ru(II) cyclometalated compounds that contain both highly selective chemotherapeutic agents and extremely potent photocytotoxic agents.
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Affiliation(s)
- Goutam Ghosh
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia B4P 2R6 , Canada
| | - Katsuya L Colón
- Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro , North Carolina 27402 , United States
| | - Anderson Fuller
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia B4P 2R6 , Canada
| | - Tariq Sainuddin
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia B4P 2R6 , Canada
| | - Evan Bradner
- Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro , North Carolina 27402 , United States
| | - Julia McCain
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia B4P 2R6 , Canada
| | - Susan M A Monro
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia B4P 2R6 , Canada
| | - Huimin Yin
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia B4P 2R6 , Canada
| | - Marc W Hetu
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia B4P 2R6 , Canada
| | - Colin G Cameron
- Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro , North Carolina 27402 , United States
| | - Sherri A McFarland
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia B4P 2R6 , Canada.,Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro , North Carolina 27402 , United States
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