1
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Karuth A, Casanola-Martin GM, Lystrom L, Sun W, Kilin D, Kilina S, Rasulev B. Combined Machine Learning, Computational, and Experimental Analysis of the Iridium(III) Complexes with Red to Near-Infrared Emission. J Phys Chem Lett 2024; 15:471-480. [PMID: 38190332 DOI: 10.1021/acs.jpclett.3c02533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
Various coordination complexes have been the subject of experimental and theoretical studies in recent decades because of their fascinating photophysical properties. In this work, a combined experimental and computational approach was applied to investigate the optical properties of monocationic Ir(III) complexes. An interpretative machine learning-based quantitative structure-property relationship (ML/QSPR) model was successfully developed that could reliably predict the emission wavelength of the Ir(III) complexes and provide a foundation for the theoretical evaluation of the optical properties of Ir(III) complexes. A hypothesis was proposed to explain the differences in the emission wavelengths between structurally different individual Ir(III) complexes. The efficacy of the developed model was demonstrated by high R2 values of 0.84 and 0.87 for the training and test sets, respectively. It is worth noting that a relationship between the N-N distance in the diimine ligands of the Ir(III) complexes and emission wavelengths is detected. This effect is most probably associated with a degree of distortion in the octahedral geometry of the complexes, resulting in a perturbed ligand field. This combined experimental and computational approach shows great potential for the rational design of new Ir(III) complexes with the desired optical properties. Moreover, the developed methodology could be extended to other transition-metal complexes.
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Affiliation(s)
- Anas Karuth
- Coatings and Polymeric Materials, North Dakota State University, Fargo, North Dakota 58108, United States
| | - Gerardo M Casanola-Martin
- Coatings and Polymeric Materials, North Dakota State University, Fargo, North Dakota 58108, United States
| | - Levi Lystrom
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108, United States
| | - Wenfang Sun
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108, United States
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Dmitri Kilin
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108, United States
| | - Svetlana Kilina
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108, United States
| | - Bakhtiyor Rasulev
- Coatings and Polymeric Materials, North Dakota State University, Fargo, North Dakota 58108, United States
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2
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Li G, Jiang Z, Tang M, Jiang X, Tu H, Zhu S, Liu R, Zhu H. Synthesis, Photophysics and Tunable Reverse Saturable Absorption of Bis-Tridentate Iridium(III) Complexes via Modification on Diimine Ligand. Molecules 2023; 28:molecules28020566. [PMID: 36677626 PMCID: PMC9864372 DOI: 10.3390/molecules28020566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 12/25/2022] [Accepted: 01/02/2023] [Indexed: 01/09/2023] Open
Abstract
Five novel bis-tridentate Ir(III) complexes (Ir-1−Ir-5) incorporating versatile N^N^C ligands and a N^C^N ligand (1,3-di(2-pyridyl)-4,6-dimethylbenzene) were synthesized. With the combination of experimental and theoretical methods, their steady and transient state characteristics were researched scientifically. The UV-visible absorption spectra show that the broadband charge transfer absorbance of those bis-tridentate Ir(III) complexes can reach 550 nm, all of these complexes reveal the long-lasting phosphorescent emission. Because the excited-state absorption is more powerful than the ground-state absorption, a sturdy reverse saturable absorption (RSA) process can ensue in the visible and near-infrared regions when the complexes are exposed to a 532 nm laser. Therefore, the optical power limiting (OPL) effect follows the trend: Ir-5 > Ir-4 ≈ Ir-3 > Ir-2 > Ir-1. Generally speaking, the expansion of π-conjugation and the introduction of electron donating/withdrawing groups on the N^N^C ligand could effectively elevate the OPL effect. Therefore, these octahedral bis-tridentate Ir(III) complexes might be exploited as potential OPL materials.
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Affiliation(s)
| | | | | | | | | | | | - Rui Liu
- Correspondence: (S.Z.); (R.L.)
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3
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Zhu S, Pan Q, Li Y, Liu W, Liu R, Zhu H. Fluorene-decorated Ir(III) complexes: synthesis, photophysics and tunable triplet excited state properties in aggregation. Dalton Trans 2022; 51:13322-13330. [PMID: 35983911 DOI: 10.1039/d2dt01592g] [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
Two new heteroleptic cationic Ir(III) complexes bearing benzothiazole and pyridine motifs on fluorene groups were synthesized and characterized. Complexes Ir1 and Ir2 exhibit 1π,π* transitions below 430 nm, with broad but weak metal-to-ligand and ligand-to-ligand charge transfer absorption bands above 430 nm. Both complexes possess long-lived emissions (τem = 0.37 μs for Ir1, τem = 5.41 μs for Ir2) and triplet excited states (τTA = 0.14 μs for Ir1, τTA = 6.06 μs for Ir2). Their optical properties in solution and aggregated states were also investigated. Both Ir(III) complexes exhibit aggregation-induced phosphorescence emission behavior in an acetonitrile-water mixture. As the water content increased to 90%, the emission intensities of complexes Ir1 and Ir2 increased nearly 3 times and 2.8 times, respectively. Moreover, nonlinear transmittance experiments were performed in CH3CN and a CH3CN-H2O mixture (fw = 90%), and the strength of the reverse saturable absorption (RSA) at 532 nm followed the trend: Ir2 (CH3CN) ≥ Ir1 (CH3CN) > Ir2 (CH3CN-H2O) > Ir1 (CH3CN-H2O). Abundant triplet state excitons participated in the radiative transition progress, which inhibited the RSA process. These results indicate that the fluorene-decorated Ir(III) complexes are suitable for aggregation emission and optical power limiting applications.
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Affiliation(s)
- Senqiang Zhu
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China.
| | - Qianqian Pan
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China.
| | - Yuhao Li
- Institute of Bismuth and Rhenium, School of Materials and Chemistry, University of Shanghai for Science and Technology, Shanghai 200093, China.
| | - Wenqing Liu
- Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China
| | - Rui Liu
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China.
| | - Hongjun Zhu
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China.
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4
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Wang X, Song K, Deng Y, Liu J, Peng Q, Lao X, Xu J, Wang D, Shi T, Li Y, Deng D, Miao Y. Benzothiazole-decorated iridium-based nanophotosensitizers for photodynamic therapy of cancer cells. Dalton Trans 2022; 51:3666-3675. [PMID: 35165680 DOI: 10.1039/d1dt04315c] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Photodynamic therapy (PDT) is an effective non-invasive treatment for tumors. The structure of a photosensitizer has an important influence on light utilization and efficiency of singlet-oxygen generation. In this study, we synthesized three π-type iridium(III) complexes and modified the C^N and N^N ligands with benzothiazole (BTZ) to regulate their light-absorption capacity and efficiency of singlet-oxygen generation. We assembled the nano-photosensitizers by wrapping them with an amphiphilic polyethylene glycol polymer with folic acid-targeting function to improve their targeting ability and biocompatibility. Modification of the BTZ group on the C^N ligand enhanced the ability of the photosensitizer to generate singlet oxygen and improved the cell uptake and PDT efficacy of the corresponding nanophotosensitizer. We believe that this type of photosensitizer provides the basis for the design of new photosensitizers based on the structure of iridium(III) complexes.
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Affiliation(s)
- Xiang Wang
- School of Materials and Chemistry & Institute of Bismuth and Rhenium Science, University of Shanghai for Science and Technology, Shanghai 200093, China.
| | - Kang Song
- School of Materials and Chemistry & Institute of Bismuth and Rhenium Science, University of Shanghai for Science and Technology, Shanghai 200093, China.
| | - Yong Deng
- School of Materials and Chemistry & Institute of Bismuth and Rhenium Science, University of Shanghai for Science and Technology, Shanghai 200093, China.
| | - Jie Liu
- School of Materials and Chemistry & Institute of Bismuth and Rhenium Science, University of Shanghai for Science and Technology, Shanghai 200093, China.
| | - Qin Peng
- School of Materials and Chemistry & Institute of Bismuth and Rhenium Science, University of Shanghai for Science and Technology, Shanghai 200093, China.
| | - Xiao Lao
- School of Materials and Chemistry & Institute of Bismuth and Rhenium Science, University of Shanghai for Science and Technology, Shanghai 200093, China.
| | - Jiayu Xu
- School of Materials and Chemistry & Institute of Bismuth and Rhenium Science, University of Shanghai for Science and Technology, Shanghai 200093, China.
| | - Dong Wang
- School of Materials and Chemistry & Institute of Bismuth and Rhenium Science, University of Shanghai for Science and Technology, Shanghai 200093, China.
| | - Turong Shi
- School of Materials and Chemistry & Institute of Bismuth and Rhenium Science, University of Shanghai for Science and Technology, Shanghai 200093, China.
| | - Yuhao Li
- School of Materials and Chemistry & Institute of Bismuth and Rhenium Science, University of Shanghai for Science and Technology, Shanghai 200093, China. .,Shanghai Collaborative Innovation Center of Energy Therapy for Tumors, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Dan Deng
- Dermatology Department, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, 200092, China.
| | - Yuqing Miao
- School of Materials and Chemistry & Institute of Bismuth and Rhenium Science, University of Shanghai for Science and Technology, Shanghai 200093, China. .,Shanghai Collaborative Innovation Center of Energy Therapy for Tumors, University of Shanghai for Science and Technology, Shanghai 200093, China
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5
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Lu J, Pan Q, Zhu S, Liu R, Zhu H. Ligand-Mediated Photophysics Adjustability in Bis-tridentate Ir(III) Complexes and Their Application in Efficient Optical Limiting Materials. Inorg Chem 2021; 60:12835-12846. [PMID: 34428896 DOI: 10.1021/acs.inorgchem.1c01142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A family of novel bis-tridentate Ir(III) complexes (Ir1-Ir5) incorporating both functional N∧C∧N-type ligands (L1-L5) and N∧N∧C-type ligand (L0) were synthesized attentively and characterized scientifically. The crystalline structures of Ir1, Ir3 and Ir4 were resoundingly confirmed by XRD. With the aid of experimental and theoretical methods, their photophysical properties at transient and steady states were scientifically investigated. The broadband charge-transfer absorption for these aforementioned Ir(III) complexes is up to 600 nm as shown in the UV-visible absorption spectrum. The emission lifetimes of their excited states are good. Between the visible and near-infrared regions, Ir1-Ir5 possessed powerful excited-state absorption. Hence, a remarkably robust reverse saturable absorption (RSA) process can occur once the complexes are irradiated by a 532 nm laser. The RSA effect follows the descending order: Ir3 > Ir5 > Ir4 ≈ Ir1 > Ir2. To sum up, modifying electron-donating units (-OCH3) and large π-conjugated units to the pyridyl N∧C∧N-type ligands is a systematic way to markedly raise the RSA effect. Therefore, these octahedral bis-tridentate Ir(III) complexes are potentially state-of-the-art optical limiting (OPL) materials.
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Affiliation(s)
- Jiapeng Lu
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Qianqian Pan
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Senqiang Zhu
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Rui Liu
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
| | - Hongjun Zhu
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, China
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6
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Ensley TR, O'Donnell RM, Mihaly JJ, Haley JE, Grusenmeyer TA, Gray TG. Two-photon absorption characterization and comparison of Au(I) fluorenyl benzothiazole complexes in the visible wavelength regime. APPLIED OPTICS 2021; 60:G199-G206. [PMID: 34613208 DOI: 10.1364/ao.427968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
We use the two-photon excited fluorescence method to determine the two-photon absorption (2PA) cross sections of three series of (fluorenyl benzothiazole) gold(I) complexes in the visible wavelength range from 570 to 700 nm. We compare the effect of ancillary ligand substitutions on the 2PA magnitudes and find that the ancillary ligand does not drastically affect either the magnitude or the shape of 2PA. Even so, moderate 2PA cross sections were measured that ranged from 10 to 1000 s of GM (Göppert-Mayer, =10-50cm4s/photon), making these types of complexes nonlinear optical materials for two-photon absorbing applications.
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7
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Yang X, Dou S, Zhang Q, Yang R, Liu Z, Li G, Niu Z. N,
N
‐heterocyclic Ancillary Ligands for Enhanced Photoluminescence Quantum Yields of Orange/Red‐Emitting 1‐(4‐(Trifluoromethyl)phenyl)isoquinoline‐Based Iridium (III) Complexes. Z Anorg Allg Chem 2021. [DOI: 10.1002/zaac.202000298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Xiao‐Han Yang
- Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province College of Chemistry and Chemical Engineering Hainan Normal University Haikou 571158 China
| | - Shao‐Bin Dou
- Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province College of Chemistry and Chemical Engineering Hainan Normal University Haikou 571158 China
| | - Qian Zhang
- Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province College of Chemistry and Chemical Engineering Hainan Normal University Haikou 571158 China
| | - Rui‐Lian Yang
- Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province College of Chemistry and Chemical Engineering Hainan Normal University Haikou 571158 China
| | - Zhuo Liu
- Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province College of Chemistry and Chemical Engineering Hainan Normal University Haikou 571158 China
| | - Gao‐Nan Li
- Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province College of Chemistry and Chemical Engineering Hainan Normal University Haikou 571158 China
| | - Zhi‐Gang Niu
- Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province College of Chemistry and Chemical Engineering Hainan Normal University Haikou 571158 China
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8
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Xu Y, Wang X, Song K, Du J, Liu J, Miao Y, Li Y. BSA-encapsulated cyclometalated iridium complexes as nano-photosensitizers for photodynamic therapy of tumor cells. RSC Adv 2021; 11:15323-15331. [PMID: 35424038 PMCID: PMC8698255 DOI: 10.1039/d1ra01740c] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 04/16/2021] [Indexed: 01/10/2023] Open
Abstract
Photodynamic therapy is a promising treatment method. The development of suitable photosensitizers can improve therapeutic efficacy. Herein, we report three iridium complexes (Ir1, Ir2, and Ir3), and encapsulate them within bovine serum albumin (BSA) to form nano-photosensitizers (Ir1@BSA, Ir2@BSA, and Ir3@BSA) for photodynamic therapy (PDT) of tumor cells. In the structures of Ir(iii) complexes, we use the pyrazine heterocycle as part of the C^N ligands and explore the effect of different ligands on the ability to generate singlet oxygen (1O2) by changing the conjugation length of the ligand and increasing the coplanarity of the ligand. Besides, the fabricated nano-photosensitizers are beneficial to improve water dispersibility and increase cellular uptake ability. Through studying photophysical properties, 1O2 generation capacity, and cellular uptake performance, the results show that Ir1@BSA has the best photodynamic therapeutic effect on 4T1 tumor cells. This study provides an effective research basis for the further design of new nano-photosensitizers. Three new iridium complexes were synthesized and fabricated with BSA to form nano-photosensitizers, which can catalyze oxygen to produce singlet oxygen to achieve photodynamic therapy of tumor cells.![]()
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Affiliation(s)
- Yao Xu
- Institute of Bismuth Science, College of Science, University of Shanghai for Science and Technology Shanghai 200093 China
| | - Xiang Wang
- Institute of Bismuth Science, College of Science, University of Shanghai for Science and Technology Shanghai 200093 China
| | - Kang Song
- Institute of Bismuth Science, College of Science, University of Shanghai for Science and Technology Shanghai 200093 China
| | - Jun Du
- Institute of Bismuth Science, College of Science, University of Shanghai for Science and Technology Shanghai 200093 China
| | - Jinliang Liu
- Institute of Bismuth Science, College of Science, University of Shanghai for Science and Technology Shanghai 200093 China
| | - Yuqing Miao
- Institute of Bismuth Science, College of Science, University of Shanghai for Science and Technology Shanghai 200093 China
| | - Yuhao Li
- Institute of Bismuth Science, College of Science, University of Shanghai for Science and Technology Shanghai 200093 China
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9
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Elgar CE, Otaif HY, Zhang X, Zhao J, Horton PN, Coles SJ, Beames JM, Pope SJA. Iridium(III) Sensitisers and Energy Upconversion: The Influence of Ligand Structure upon TTA-UC Performance. Chemistry 2021; 27:3427-3439. [PMID: 33242225 DOI: 10.1002/chem.202004146] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/20/2020] [Indexed: 12/21/2022]
Abstract
Six substituted ligands based upon 2-(naphthalen-1-yl)quinoline-4-carboxylate and 2-(naphthalen-2-yl)quinoline-4-carboxylate have been synthesised in two steps from a range of commercially available isatin derivatives. These species are shown to be effective cyclometallating ligands for IrIII , yielding complexes of the form [Ir(C^N)2 (bipy)]PF6 (where C^N=cyclometallating ligand; bipy=2,2'-bipyridine). X-ray crystallographic studies on three examples demonstrate that the complexes adopt a distorted octahedral geometry wherein a cis-C,C and trans-N,N coordination mode is observed. Intraligand torsional distortions are evident in all cases. The IrIII complexes display photoluminescence in the red part of the visible region (668-693 nm), which is modestly tuneable through the ligand structure. The triplet lifetimes of the complexes are clearly influenced by the precise structure of the ligand in each case. Supporting computational (DFT) studies suggest that the differences in observed triplet lifetime are likely due to differing admixtures of ligand-centred versus MLCT character instilled by the facets of the ligand structure. Triplet-triplet annihilation upconversion (TTA-UC) measurements demonstrate that the complexes based upon the 1-naphthyl derived ligands are viable photosensitisers with upconversion quantum efficiencies of 1.6-6.7 %.
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Affiliation(s)
- Christopher E Elgar
- School of Chemistry, Cardiff University, Main Building, Cardiff, CF10 3AT, Cymru/Wales, UK
| | - Haleema Y Otaif
- School of Chemistry, Cardiff University, Main Building, Cardiff, CF10 3AT, Cymru/Wales, UK
| | - Xue Zhang
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, 116024, P. R. China
| | - Jianzhang Zhao
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, 116024, P. R. China
| | - Peter N Horton
- UK National Crystallographic Service, Chemistry, Faculty of Natural and Environmental Sciences, University of Southampton, Highfield, Southampton, SO17 1BJ, UK
| | - Simon J Coles
- UK National Crystallographic Service, Chemistry, Faculty of Natural and Environmental Sciences, University of Southampton, Highfield, Southampton, SO17 1BJ, UK
| | - Joseph M Beames
- School of Chemistry, Cardiff University, Main Building, Cardiff, CF10 3AT, Cymru/Wales, UK
| | - Simon J A Pope
- School of Chemistry, Cardiff University, Main Building, Cardiff, CF10 3AT, Cymru/Wales, UK
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10
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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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11
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Deng Y, Wang X, Liu Y, Xu Y, Zhang J, Huang F, Li B, Miao Y, Sun Y, Li Y. Dual-light triggered metabolizable nano-micelles for selective tumor-targeted photodynamic/hyperthermia therapy. Acta Biomater 2021; 119:323-336. [PMID: 33122146 DOI: 10.1016/j.actbio.2020.10.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 10/05/2020] [Accepted: 10/22/2020] [Indexed: 01/25/2023]
Abstract
Phototherapy, including photodynamic and photothermal therapies, is a non-invasive photo-triggered tumor treatment. Combination therapy and new synergistic therapeutic reagents may hold promise for improving these treatments. Herein, we report an amphiphilic iridium-based photosensitizer (C14-IP2000) loaded with a hydrophobic photo-thermal drug (ZnPc) to form nano-micelles (ZNPs) for dual-light triggered tumor phototherapy. The C14-IP2000 was contained within ZNPs consisting of an iridium complex core decorated with hydrophilic polyethylene glycol chains to extend the time in blood circulation, and two hydrophobic carbon chains to enhance the loading capacity and the hydrophobic interaction with the loaded reagent. The designed ZNPs showed effective blood circulation, passive tumor targeting ability, remarkable photodynamic conversion ability, and good photothermal conversion capability, and therefore may be used for combined tumor ablation. Our results demonstrated that the amphipathic bionic structure of ZNPs not only enables self-assembled reagent fabrication with prolonged circulation time and favorable metabolic characteristics for tumor combination therapy, but also provides a nanostructure strategy for the modification of functionalized reagents.
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Affiliation(s)
- Yong Deng
- Institute of Bismuth Science, College of Science, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Xiang Wang
- Institute of Bismuth Science, College of Science, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Yongtian Liu
- Institute of Bismuth Science, College of Science, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Yao Xu
- Institute of Bismuth Science, College of Science, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Jing Zhang
- Institute of Bismuth Science, College of Science, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Fei Huang
- Institute of Bismuth Science, College of Science, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Bing Li
- Department of Research and Development & Department of Nuclear Medicine, Shanghai Proton and Heavy Ion Center, Fudan University Shanghai Cancer Center, Shanghai 201321, China; Shanghai Engineering Research Center of Proton and Heavy Ion Radiation Therapy, Shanghai 201321, China
| | - Yuqing Miao
- Institute of Bismuth Science, College of Science, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Yun Sun
- Department of Research and Development & Department of Nuclear Medicine, Shanghai Proton and Heavy Ion Center, Fudan University Shanghai Cancer Center, Shanghai 201321, China; Shanghai Engineering Research Center of Proton and Heavy Ion Radiation Therapy, Shanghai 201321, China.
| | - Yuhao Li
- Institute of Bismuth Science, College of Science, University of Shanghai for Science and Technology, Shanghai 200093, China.
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12
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Zhu X, Liu B, Cui P, Kilina S, Sun W. Multinuclear 2-(Quinolin-2-yl)quinoxaline-Coordinated Iridium(III) Complexes Tethered by Carbazole Derivatives: Synthesis and Photophysics. Inorg Chem 2020; 59:17096-17108. [PMID: 33170657 DOI: 10.1021/acs.inorgchem.0c02366] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Five mono/di/trinuclear iridium(III) complexes (1-5) bearing the carbazole-derivative-tethered 2-(quinolin-2-yl)quinoxaline (quqo) diimine (N^N) ligand were synthesized and characterized. The photophysical properties of these complexes and their corresponding diimine ligands were systematically studied via UV-vis absorption, emission, and transient absorption (TA) spectroscopy and simulated by time-dependent density functional theory. All complexes possessed strong well-resolved absorption bands at <400 nm that have predominant ligand-based 1π,π* transitions and broad structureless charge-transfer (1CT) absorption bands at 400-700 nm. The energies or intensities of these 1CT bands varied pronouncedly when the number of tethered Ir(quqo)(piq)2+ (piq refers to 1-phenylisoquinoline) units, π conjugation of the carbazole derivative linker, or attachment positions on the carbazole linker were altered. All complexes were emissive at room temperature, with 1-3 showing near-IR (NIR) 3MLCT (metal-to-ligand charge-transfer)/3LLCT (ligand-to-ligand charge-transfer) emission at ∼710 nm and 4 and 5 exhibiting red or NIR 3ILCT (intraligand charge-transfer)/3LMCT (ligand-to-metal charge-transfer) emission in CH2Cl2. In CH3CN, 1-3 displayed an additional emission band at ca. 590 nm (3ILCT/3LMCT/3MLCT/3π,π* in nature) in addition to the 710 nm band. The different natures of the emitting states of 1-3 versus those of 4 and 5 also gave rise to different spectral features in their triplet TA spectra. It appears that the parentage and characteristics of the lowest triplet excited states in these complexes are mainly impacted by the π systems of the bridging carbazole derivatives and essentially no interactions among the Ir(quqo)(piq)2+ units. In addition, all of the diimine ligands tethered by the carbazole derivatives displayed a dramatic solvatochromic effect in their emission due to the predominant intramolecular charge-transfer nature of their emitting states. Aggregation-enhanced emission was also observed from the mixed CH2Cl2/ethyl acetate or CH2Cl2/hexane solutions of these ligands.
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Affiliation(s)
- Xiaolin Zhu
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
| | - Bingqing Liu
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
| | - Peng Cui
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States.,Materials and Nanotechnology Program, North Dakota State University, Fargo, North Dakota 58108-6050, United States.,Key Laboratory of Eco-textiles, Ministry of Education, Jiangnan University, Wuxi, Jiangsu Province 214122, P. R. China
| | - Svetlana Kilina
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
| | - Wenfang Sun
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
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13
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Li H, Liu S, Lystrom L, Kilina S, Sun W. Improving triplet excited-state absorption and lifetime of cationic iridium(III) complexes by extending π-conjugation of the 2-(2-quinolinyl)quinoxaline ligand. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112609] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Zhu S, Hu L, Gu L, Liu R, Zhu H. Heteroleptic Ir(iii) complexes with varied π-conjugated diimine ligands: synthesis, tunable triplet states and nonlinear absorption properties. Dalton Trans 2020; 49:7945-7951. [PMID: 32495779 DOI: 10.1039/d0dt01207f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Four heteroleptic Ir(iii) complexes (Ir-1-Ir-4) with varied π-conjugated diimine ligands were synthesized. Their optical properties were investigated systematically via spectroscopic methods, in order to elucidate the influence of the extended π-conjugation on the singlet and triplet states of the molecules. All these Ir(iii) complexes exhibit ligand localized 1π,π* transitions below 370 nm, and broad metal-to-ligand and ligand-to-ligand charge transfer (MLCT/LLCT) absorption bands in the visible region. Extending the π-conjugation in diimine ligands influences the electron distribution of the triplet state. The 3π,π* dominated Ir(iii) complexes (Ir-3 and Ir-4) exhibit long-lived triplet states and low phosphorescence quantum yields, compared with the charge transfer dominated Ir(iii) complexes (Ir-1 and Ir-2). Complexes Ir-3 and Ir-4 exhibit broadband transient absorption spectra from 420 to 750 nm, between which the nonlinear absorption could be observed by virtue of reverse saturable absorption. The results of nonlinear transmission measurements using 532 nm laser pulses further elucidate that selected complexes Ir-3 and Ir-4 are promising candidates for optical limiting applications.
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Affiliation(s)
- Senqiang Zhu
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China.
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15
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Liu B, Jabed MA, Kilina S, Sun W. Synthesis, Photophysics, and Reverse Saturable Absorption of trans-Bis-cyclometalated Iridium(III) Complexes (C^N^C)Ir(R-tpy) + (tpy = 2,2':6',2″-Terpyridine) with Broadband Excited-State Absorption. Inorg Chem 2020; 59:8532-8542. [PMID: 32497429 DOI: 10.1021/acs.inorgchem.0c00961] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Extending the bandwidth of triplet excited-state absorption in transition-metal complexes is appealing for developing broadband reverse saturable absorbers. Targeting this goal, five bis-terdentate iridium(III) complexes (Ir1-Ir5) bearing trans-bis-cyclometalating (C^N^C) and 4'-R-2,2':6',2″-terpyridine (4'-R-tpy) ligands were synthesized. The effects of the structural variation in cyclometalating ligands and substituents at the tpy ligand on the photophysics of these complexes have been systematically explored using spectroscopic methods (i.e., UV-vis absorption, emission, and transient absorption spectroscopy) and time-dependent density functional theory (TDDFT) calculations. All complexes exhibited intensely structured 1π,π* absorption bands at <400 nm and broad charge transfer (1CT)/1π,π* transitions at 400-600 nm. Ligand structural variations exerted a very small effect on the energies of the 1CT/1π,π* transitions; however, they had a significant effect on the molar extinction coefficients of these absorption bands. All complexes emitted featureless deep red phosphorescence in solutions at room temperature and gave broad-band and strong triplet excited-state absorption ranging from the visible to the near-infrared (NIR) spectral regions, with both originating from the 3π,π*/3CT states. Although alteration of the ligand structures influenced the emission energies slightly, these changes significantly affected the emission lifetimes and quantum yields, transient absorption spectral features, and the triplet excited-state quantum yields of the complexes. Except for Ir3, the other four complexes all manifested reverse saturable absorption (RSA) upon nanosecond laser pulse excitation at 532 nm, with the decreasing trend of RSA following Ir2 ≈ Ir4 > Ir1 > Ir5 > Ir3. The RSA trend corresponded well with the strength of the excited-state and ground-state absorption differences (ΔOD) at 532 nm for these complexes.
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Affiliation(s)
- Bingqing Liu
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota58108-6050, United States
| | - Mohammed A Jabed
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota58108-6050, United States
| | - Svetlana Kilina
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota58108-6050, United States
| | - Wenfang Sun
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota58108-6050, United States
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16
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Mdluli V, Diluzio S, Lewis J, Kowalewski JF, Connell TU, Yaron D, Kowalewski T, Bernhard S. High-throughput Synthesis and Screening of Iridium(III) Photocatalysts for the Fast and Chemoselective Dehalogenation of Aryl Bromides. ACS Catal 2020. [DOI: 10.1021/acscatal.0c02247] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Velabo Mdluli
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Stephen Diluzio
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Jacqueline Lewis
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Jakub F. Kowalewski
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Timothy U. Connell
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - David Yaron
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Tomasz Kowalewski
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Stefan Bernhard
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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17
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Stonelake T, Phillips KA, Otaif HY, Edwardson ZC, Horton PN, Coles SJ, Beames JM, Pope SJA. Spectroscopic and Theoretical Investigation of Color Tuning in Deep-Red Luminescent Iridium(III) Complexes. Inorg Chem 2020; 59:2266-2277. [PMID: 32013422 PMCID: PMC7145353 DOI: 10.1021/acs.inorgchem.9b02991] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Indexed: 12/03/2022]
Abstract
A series of heteroleptic, neutral iridium(III) complexes of the form [Ir(L)2(N^O)] (where L = cyclometalated 2,3-disubstituted quinoxaline and N^O = ancillary picolinate or pyrazinoate) are described in terms of their synthesis and spectroscopic properties, with supporting computational analyses providing additional insight into the electronic properties. The 10 [Ir(L)2(N^O)] complexes were characterized using a range of analytical techniques (including 1H, 13C, and 19F NMR and IR spectroscopies and mass spectrometry). One of the examples was structurally characterized using X-ray diffraction. The redox properties were determined using cyclic voltammetry, and the electronic properties were investigated using UV-vis, time-resolved luminescence, and transient absorption spectroscopies. The complexes are phosphorescent in the red region of the visible spectrum (λem = 633-680 nm), with lifetimes typically of hundreds of nanoseconds and quantum yields ca. 5% in aerated chloroform. A combination of spectroscopic and computational analyses suggests that the long-wavelength absorption and emission properties of these complexes are strongly characterized by a combination of spin-forbidden metal-to-ligand charge-transfer and quinoxaline-centered transitions. The emission wavelength in these complexes can thus be controlled in two ways: first, substitution of the cyclometalating quinoxaline ligand can perturb both the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital levels (LUMO, Cl atoms on the ligand induce the largest bathochromic shift), and second, the choice of the ancillary ligand can influence the HOMO energy (pyrazinoate stabilizes the HOMO, inducing hypsochromic shifts).
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Affiliation(s)
- Thomas
M. Stonelake
- School
of Chemistry, Cardiff University, Main Building, Cardiff CF10 3AT, Wales
| | - Kaitlin A. Phillips
- School
of Chemistry, Cardiff University, Main Building, Cardiff CF10 3AT, Wales
| | - Haleema Y. Otaif
- School
of Chemistry, Cardiff University, Main Building, Cardiff CF10 3AT, Wales
| | | | - Peter N. Horton
- U.K.
National Crystallographic Service, Chemistry, Faculty of Natural and
Environmental Sciences, University of Southampton, Highfield, Southampton SO17 1BJ, U.K.
| | - Simon J. Coles
- U.K.
National Crystallographic Service, Chemistry, Faculty of Natural and
Environmental Sciences, University of Southampton, Highfield, Southampton SO17 1BJ, U.K.
| | - Joseph M. Beames
- School
of Chemistry, Cardiff University, Main Building, Cardiff CF10 3AT, Wales
| | - Simon J. A. Pope
- School
of Chemistry, Cardiff University, Main Building, Cardiff CF10 3AT, Wales
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18
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Wang L, Cui P, Lystrom L, Lu J, Kilina S, Sun W. Heteroleptic cationic iridium( iii) complexes bearing phenanthroline derivatives with extended π-conjugation as potential broadband reverse saturable absorbers. NEW J CHEM 2020. [DOI: 10.1039/c9nj03877a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Fluorenyl substitution at the diimine ligand broadened the excited-state absorption to near-IR, and enhanced reverse saturable absorption at 532 nm for the cationic Ir(iii) complexes.
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Affiliation(s)
- Li Wang
- Department of Chemistry and Biochemistry
- North Dakota State University
- Fargo
- USA
| | - Peng Cui
- Department of Chemistry and Biochemistry
- North Dakota State University
- Fargo
- USA
- Materials and Nanotechnology Program
| | - Levi Lystrom
- Department of Chemistry and Biochemistry
- North Dakota State University
- Fargo
- USA
| | - Jiapeng Lu
- Department of Chemistry and Biochemistry
- North Dakota State University
- Fargo
- USA
| | - Svetlana Kilina
- Department of Chemistry and Biochemistry
- North Dakota State University
- Fargo
- USA
| | - Wenfang Sun
- Department of Chemistry and Biochemistry
- North Dakota State University
- Fargo
- USA
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19
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Liu B, Jabed MA, Guo J, Xu W, Brown SL, Ugrinov A, Hobbie EK, Kilina S, Qin A, Sun W. Neutral Cyclometalated Iridium(III) Complexes Bearing Substituted N-Heterocyclic Carbene (NHC) Ligands for High-Performance Yellow OLED Application. Inorg Chem 2019; 58:14377-14388. [DOI: 10.1021/acs.inorgchem.9b01678] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Bingqing Liu
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
| | - Mohammed A. Jabed
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
| | - Jiali Guo
- School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, People’s Republic of China
| | - Wan Xu
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
- Engineering Research Center for Nanomaterials, Henan University, Kaifeng 475004, People’s Republic of China
| | - Samuel L. Brown
- Materials and Nanotechnology Program, North Dakota State University, Fargo, North Dakota 58108-6050, United States
| | - Angel Ugrinov
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
| | - Erik K. Hobbie
- Materials and Nanotechnology Program, North Dakota State University, Fargo, North Dakota 58108-6050, United States
| | - Svetlana Kilina
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
| | - Anjun Qin
- School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, People’s Republic of China
| | - Wenfang Sun
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
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20
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Wang J, Zhu S, Liu R, Tang M, Su H, Cai X, Zhu H. Cyclometalated iridium(III) complex containing indolinyl-based phenanthroline ligand: Synthesis, structure and photophysical properties. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2019.04.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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21
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Liu B, Lystrom L, Brown SL, Hobbie EK, Kilina S, Sun W. Impact of Benzannulation Site at the Diimine (N^N) Ligand on the Excited-State Properties and Reverse Saturable Absorption of Biscyclometalated Iridium(III) Complexes. Inorg Chem 2019; 58:5483-5493. [PMID: 31060198 DOI: 10.1021/acs.inorgchem.8b03162] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Ten biscyclometalated monocationic Ir(III) complexes were synthesized and studied to elucidate the effects of extending π-conjugation of the diimine ligand (N^N = 2,2'-bipyridine in Ir1, 2-(pyridin-2-yl)quinoline in Ir2, 2-(pyridin-2-yl)[6,7]benzoquinoline in Ir3, 2-(pyridin-2-yl)-[7,8]benzoquinoline in Ir4, phenanthroline in Ir5, benzo[ f][1,10]phenanthroline in Ir6, naphtho[2,3- f][1,10]phenanthroline in Ir7, 2,2'-bisquinoline in Ir8, 3,3'-biisoquinoline in Ir9, and 1,1'-biisoquinoline in Ir10) via benzannulation at 2,2'-bipyridine on the excited-state properties and reverse saturable absorption (RSA) of these complexes. Either a bathochromic or a hypsochromic shift of the charge-transfer absorption band and emission spectrum was observed depending on the benzannulation site at the 2,2'-bipyridine ligand. Benzannulation at the 3,4-/3',4'-position or 5,6-/5',6'-position of 2,2'-bipyridine ligand or at the 6,7-position of the quinoline ring on the N^N ligand caused red-shifted charge-transfer absorption band and emission band for complexes Ir2, Ir8, Ir10 vs Ir1 and Ir3 vs Ir2, while benzannulation at the 4,5-/4',5'-position of 2,2'-bipyridine ligand or at the 7,8-position of the quinoline ring on the N^N ligand induced a blue shift of the charge-transfer absorption and emission bands for complex Ir9 vs Ir1 and Ir4 vs Ir2. However, benzannulation at the 2,2',3,3'-position of 2,2'-bipyridine or 5,6-position of phenanthroline ligand had no impact on the energy of the charge-transfer absorption band and emission band of complexes Ir5-Ir7 compared with those of Ir1. The observed phenomenon was explained by the frontier molecular orbital (FMO) symmetry analysis. Site-dependent benzannulation also impacted the spectral feature and intensity of the triplet transient absorption spectra and lifetimes drastically. Consequently, the RSA strength of these complexes varied with a trend of Ir7 > Ir5 ≈ Ir6 ≈ Ir1 > Ir3 > Ir2 > Ir10 > Ir4 > Ir8 > Ir9 at 532 nm for 4.1 ns laser pulses.
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Affiliation(s)
- Bingqing Liu
- Department of Chemistry and Biochemistry , North Dakota State University , Fargo , North Dakota 58108-6050 , United States
| | - Levi Lystrom
- Department of Chemistry and Biochemistry , North Dakota State University , Fargo , North Dakota 58108-6050 , United States
| | - Samuel L Brown
- Materials and Nanotechnology Program , North Dakota State University , Fargo , North Dakota 58108-6050 , United States
| | - Erik K Hobbie
- Materials and Nanotechnology Program , North Dakota State University , Fargo , North Dakota 58108-6050 , United States
| | - Svetlana Kilina
- Department of Chemistry and Biochemistry , North Dakota State University , Fargo , North Dakota 58108-6050 , United States
| | - Wenfang Sun
- Department of Chemistry and Biochemistry , North Dakota State University , Fargo , North Dakota 58108-6050 , United States
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22
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Liu B, Lystrom L, Cameron CG, Kilina S, McFarland SA, Sun W. Monocationic Iridium(III) Complexes with Far‐Red Charge‐Transfer Absorption and Near‐IR Emission: Synthesis, Photophysics, and Reverse Saturable Absorption. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201900156] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Bingqing Liu
- Department of Chemistry and Biochemistry North Dakota State University Fargo North Dakota 58108‐6050 USA
| | - Levi Lystrom
- Department of Chemistry and Biochemistry North Dakota State University Fargo North Dakota 58108‐6050 USA
| | - Colin G. Cameron
- Department of Chemistry and Biochemistry University of North Carolina at Greensboro Greensboro North Carolina 27402‐6170 USA
| | - Svetlana Kilina
- Department of Chemistry and Biochemistry North Dakota State University Fargo North Dakota 58108‐6050 USA
| | - Sherri A. McFarland
- Department of Chemistry and Biochemistry University of North Carolina at Greensboro Greensboro North Carolina 27402‐6170 USA
| | - Wenfang Sun
- Department of Chemistry and Biochemistry North Dakota State University Fargo North Dakota 58108‐6050 USA
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23
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Liu B, Lystrom L, Kilina S, Sun W. Effects of Varying the Benzannulation Site and π Conjugation of the Cyclometalating Ligand on the Photophysics and Reverse Saturable Absorption of Monocationic Iridium(III) Complexes. Inorg Chem 2018; 58:476-488. [PMID: 30525520 DOI: 10.1021/acs.inorgchem.8b02714] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A series of monocationic iridium(III) complexes, [Ir(C^N)2(pqu)]+PF6- [pqu = 2-(pyridin-2-yl)quinoline, C^N = 2-phenylquinoline (1), 3-phenylisoquinoline (2), 1-phenylisoquinoline (3), benzo[ h]quinoline (4), 2-(pyridin-2-yl)naphthalene (5), 1-(pyridin-2-yl)naphthalene (6), 2-(phenanthren-9-yl)pyridine (7), 2-phenylbenzo[ g]quinoline (8), 2-(naphthalen-2-yl)quinoline (9), and 2-(naphthalen-2-yl)benzo[ g]quinoline (10)], were synthesized in this work. These complexes bear C^N ligands with varied degrees of π conjugation and sites of benzannulation, allowing for elucidation of the effects of the benzannulation site at the C^N ligand on the photophysics of the complexes. Ultraviolet-visible (UV-vis) absorption and emission of the complexes were systematically investigated via spectroscopic techniques and time-dependent density functional theory calculations. Their triplet excited-state absorption and reverse saturable absorption (RSA) were studied by nanosecond transient absorption (TA) spectroscopy and nonlinear transmission techniques. The fusion of phenyl ring(s) to the phenyl ring or the 4 and 5 positions of the pyridyl ring of the C^N ligand resulted in red-shifted UV-vis absorption and emission spectra in complexes 2, 5-7, 9, and 10 compared to those of the parent complex 0, while their triplet lifetimes and emission quantum yields were significantly reduced. In contrast, the fusion of one phenyl ring to the other sites of the pyridyl group of the C^N ligand showed an insignificant impact on the energies of the lowest singlet (S1) and triplet (T1) excited states in complexes 1, 3, and 4 but noticeably affected their TA spectral features. The fusion of the naphthyl group to the 5 and 6 and positions at the pyridyl ring did not influence the S1 energy of complex 8 but altered the nature of the T1 states in 8 and 10 by switching them to the benzo[ g]quinoline-localized 3π,π* state, which resulted in completely different emission and TA spectra in these two complexes. The site-dependent variations of the ground- and excited-state absorption induced strong but varied RSA from these complexes for 4.1-ns laser pulses at 532 nm, with the RSA strength decreasing in the trend of 3 > 7 ≈ 4 ≈ 9 ≈ 6 > 8 ≈ 1 ≈ 2 ≈ 5 > 10.
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Affiliation(s)
- Bingqing Liu
- Department of Chemistry and Biochemistry , North Dakota State University , Fargo , North Dakota 58108-6050 , United States
| | - Levi Lystrom
- Department of Chemistry and Biochemistry , North Dakota State University , Fargo , North Dakota 58108-6050 , United States
| | - Svetlana Kilina
- Department of Chemistry and Biochemistry , North Dakota State University , Fargo , North Dakota 58108-6050 , United States
| | - Wenfang Sun
- Department of Chemistry and Biochemistry , North Dakota State University , Fargo , North Dakota 58108-6050 , United States
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24
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Yang LX, Yang WF, Yuan YJ, Su YB, Zhou MM, Liu XL, Chen GH, Chen X, Yu ZT, Zou ZG. Visible-Light-Driven Hydrogen Production and Polymerization using Triarylboron-Functionalized Iridium(III) Complexes. Chem Asian J 2018; 13:1699-1709. [PMID: 29722159 DOI: 10.1002/asia.201800455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 04/24/2018] [Indexed: 11/12/2022]
Abstract
The development of novel iridium(III) complexes has continued as an important area of research owing to their highly tunable photophysical properties and versatile applications. In this report, three heteroleptic dimesitylboron-containing iridium(III) complexes, [Ir(p-B-ppy)2 (N^N)]+ {p-B-ppy=2-(4-dimesitylborylphenyl)pyridine; N^N=dipyrido[3,2-a:2',3'-c]phenazine (dppz) (1), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq) (2), and 1,10-phenanthroline (phen) (3)}, were prepared and fully characterized electrochemically, photophysically, and computationally. Altering the conjugated length of the N^N ligands allowed us to tailor the photophysical properties of these complexes, especially their luminescence wavelength, which could be adjusted from λ=583 to 631 nm in CH2 Cl2 . All three complexes were evaluated as visible-light-absorbing sensitizers for the photogeneration of hydrogen from water and as photocatalysts for the photopolymerization of methyl methacrylate. The results showed that all of them were active in both photochemical reactions. High activity for the photosensitizer (over 1158 turnover numbers with 1) was observed, and the system generated hydrogen even after 20 h. Additionally, poly(methyl methacrylate) with a relatively narrow molecular-weight distribution was obtained if an initiator (i.e., ethyl α-bromophenylacetate) was used. The living character of the photoinduced polymerization was confirmed on the basis of successful chain-extension experiments.
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Affiliation(s)
- Ling-Xia Yang
- National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu, 210093, China.,National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China
| | - Wan-Fa Yang
- National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Yong-Jun Yuan
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, Zhejiang, 310018, China
| | - Yi-Bing Su
- National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu, 210093, China.,National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China
| | - Miao-Miao Zhou
- Department of Chemistry, Shantou University, Guangdong, 515063, China
| | - Xiao-Le Liu
- Department of Chemistry, Shantou University, Guangdong, 515063, China
| | - Guang-Hui Chen
- Department of Chemistry, Shantou University, Guangdong, 515063, China
| | - Xin Chen
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China
| | - Zhen-Tao Yu
- National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Zhi-Gang Zou
- National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu, 210093, China
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25
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Wang C, Lystrom L, Yin H, Hetu M, Kilina S, McFarland SA, Sun W. Increasing the triplet lifetime and extending the ground-state absorption of biscyclometalated Ir(iii) complexes for reverse saturable absorption and photodynamic therapy applications. Dalton Trans 2018; 45:16366-16378. [PMID: 27711764 DOI: 10.1039/c6dt02416e] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The synthesis, photophysics, reverse saturable absorption, and photodynamic therapeutic effect of six cationic biscyclometalated Ir(iii) complexes (1-6) with extended π-conjugation on the diimine ligand and/or the cyclometalating ligands are reported in this paper. All complexes possess ligand-localized 1π,π* absorption bands below 400 nm and charge-transfer absorption bands above 400 nm. They are all emissive in the 500-800 nm range in deoxygenated solutions at room temperature. All complexes exhibit strong and broad triplet excited-state absorption at 430-800 nm, and thus strong reverse saturable absorption for ns laser pulses at 532 nm. Complexes 1-4 are strong reverse saturable absorbers at 532 nm, while complex 6 could be a good candidate as a broadband reverse saturable absorber at 500-850 nm. The degree of π-conjugation of the diimine ligand mainly influences the 1π,π* transitions in their UV-vis absorption spectra, while the degree of π-conjugation of the cyclometalating ligand primarily affects the nature and energies of the lowest singlet and emitting triplet excited states. However, the lowest-energy triplet excited states for complexes 3-6 that contain the same benzo[i]dipyrido[3,2-a:2',3'-c]phenazine (dppn) diimine ligand but different cyclometalating ligands remain the same as the dppn ligand-localized 3π,π* state, which gives rise to the long-lived, strong excited-state absorption in the visible to the near-IR region. All of the complexes exhibit a photodynamic therapeutic effect upon visible or red light activation, with complex 6 possessing the largest phototherapeutic index reported to date (>400) for an Ir(iii) complex. Interactions with biological targets such as DNA suggest that a novel mechanism of action may be at play for the photosensitizing effect. These Ir(iii) complexes also produce strong intracellular luminescence that highlights their potential as theranostic agents.
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Affiliation(s)
- Chengzhe Wang
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, USA.
| | - Levi Lystrom
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, USA.
| | - Huimin Yin
- Department of Chemistry, Acadia University, 6 University Avenue, Wolfville, NS B4P 2R6, Canada.
| | - Marc Hetu
- Department of Chemistry, Acadia University, 6 University Avenue, Wolfville, NS B4P 2R6, Canada.
| | - Svetlana Kilina
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, USA.
| | - Sherri A McFarland
- Department of Chemistry, Acadia University, 6 University Avenue, Wolfville, NS B4P 2R6, Canada. and Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402-6170, USA.
| | - Wenfang Sun
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, USA.
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26
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Zhu X, Cui P, Kilina S, Sun W. Multifunctional Cationic Iridium(III) Complexes Bearing 2-Aryloxazolo[4,5-f][1,10]phenanthroline (N^N) Ligand: Synthesis, Crystal Structure, Photophysics, Mechanochromic/Vapochromic Effects, and Reverse Saturable Absorption. Inorg Chem 2017; 56:13715-13731. [PMID: 29083889 DOI: 10.1021/acs.inorgchem.7b01472] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of 2-aryloxazolo[4,5-f][1,10]phenanthroline ligands (N^N ligands) and their cationic iridium(III) complexes (1-11, aryl = 4-NO2-phenyl (1), 4-Br-phenyl (2), Ph (3), 4-NPh2-phenyl (4), 4-NH2-phenyl (5), pyridin-4-yl (6), naphthalen-1-yl (7), naphthalen-2-yl (8), phenanthren-9-yl (9), anthracen-9-yl (10), and pyren-1-yl (11)) were synthesized and characterized. By introducing different electron-donating or electron-withdrawing substituents at the 4-position of the 2-phenyl ring (1-5), or different aromatic substituents with varied degrees of π-conjugation (6-11) on oxazolo[4,5-f][1,10]phenanthroline ligand, we aim to understand the effects of terminal substituents at the N^N ligands on the photophysics of cationic Ir(III) complexes using both spectroscopic methods and quantum chemistry calculations. Complexes with the 4-R-phenyl substituents adopted an almost coplanar structure with the oxazolo[4,5-f][1,10]phenanthroline motif, while the polycyclic aryl substituents (except for naphthalen-2-yl) were twisted away from the oxazolo[4,5-f][1,10]phenanthroline motif. All complexes possessed strong absorption bands below 350 nm that emanated from the ligand-localized 1π,π*/1ILCT (intraligand charge transfer) transitions, mixed with 1LLCT (ligand-to-ligand charge transfer)/1MLCT (metal-to-ligand charge transfer) transitions. At the range of 350-570 nm, all complexes exhibited moderately strong 1ILCT/1LLCT/1MLCT transitions at 350-450 nm, and broad but very weak 3LLCT/3MLCT absorption at 450-570 nm. Most of the complexes demonstrated moderate to strong room temperature phosphorescence both in solution and in the solid state. Among them, complex 7 also manifested a drastic mechanochromic and vapochromic luminescence effect. Except for complexes 1 and 4 that contain NO2 or NPh2 substituent at the phenyl ring, respectively, all other complexes exhibited moderate to strong triplet excited-state absorption in the spectral region of 440-750 nm. Moderate to very strong reverse saturable absorption (RSA) of these complexes appeared at 532 nm for 4.1 ns laser pulses. The RSA strength followed the trend of 7 > 11 > 9 > 3 > 2 ≈ 4 > 5 ≈ 10 ≈ 6 ≈ 8 > 1. The photophysical studies revealed that the different 2-aryl substituents on the oxazole ring impacted the singlet and triplet excited-state characteristics dramatically, which in turn notably influenced the RSA of these complexes.
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Affiliation(s)
- Xiaolin Zhu
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
| | - Peng Cui
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States.,Materials and Nanotechnology Program, North Dakota State University , Fargo, North Dakota 58105, United States
| | - Svetlana Kilina
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
| | - Wenfang Sun
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
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27
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Liu B, Lystrom L, Kilina S, Sun W. Tuning the Ground State and Excited State Properties of Monocationic Iridium(III) Complexes by Varying the Site of Benzannulation on Diimine Ligand. Inorg Chem 2017; 56:5361-5370. [PMID: 28398733 DOI: 10.1021/acs.inorgchem.7b00467] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Extending π-conjugation of the diimine ligand (N^N ligand) via benzannulation is a common way to tune the absorption and emission energies of cationic iridium(III) complexes. However, it can cause either a red- or blue-shift of the absorption and emission bands depending on the site of benzannulation. To understand the mechanism of changes in optical transitions upon benzannulation on the diimine ligand, a series of new cationic iridium(III) complexes [Ir(dppi)2(N^N)]PF6 (1-6) (where dppi =1,2-diphenylpyreno[4,5-d]imidazole; N^N = 2-(pyridin-2-yl)quinoline (1), 2-(pyridin-2-yl)[7,8]benzoquinoline (2), 2,2'-bisquinoline (3), 2-(quinolin-2-yl)[7,8]benzoquinoline (4), 2-(pyridin-2-yl)[6,7]benzoquinoline (5), 2-(quinolin-2-yl)[6,7]benzoquinoline (6)) containing diimine ligand with varied degrees of π-conjugation via benzannulation at different sites of the 2-(pyridin-2-yl)quinoline ligand were synthesized. Experimental results and density functional theory (DFT) calculations revealed that benzannulation at the 6,7-position of quinoline and/or the 5',6'-position of pyridine (3, 5, and 6) induced red-shifts in their absorption and emission bands with respect to the parent complex 1; while benzannulation at the 7,8-position of quinoline resulted in blue-shifts (2 vs 1 and 4 vs 3). This phenomenon was rationalized by the symmetry of the frontier molecular orbitals at the site of benzannulation, which stabilized or destabilized the lowest unoccupied molecular orbital (LUMO) upon interactions with 1,3-butadiene, while the energy of the highest occupied molecular orbital (HOMO) remained nearly the same. This discovery would enable a rational design of organic or organometallic compounds that have predetermined absorption and emission energies.
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Affiliation(s)
- Bingqing Liu
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
| | - Levi Lystrom
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
| | - Svetlana Kilina
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
| | - Wenfang Sun
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
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28
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Wang L, Yin H, Jabed MA, Hetu M, Wang C, Monro S, Zhu X, Kilina S, McFarland SA, Sun W. π-Expansive Heteroleptic Ruthenium(II) Complexes as Reverse Saturable Absorbers and Photosensitizers for Photodynamic Therapy. Inorg Chem 2017; 56:3245-3259. [PMID: 28263079 DOI: 10.1021/acs.inorgchem.6b02624] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Five heteroleptic tris-diimine ruthenium(II) complexes [RuL(N^N)2](PF6)2 (where L is 3,8-di(benzothiazolylfluorenyl)-1,10-phenanthroline and N^N is 2,2'-bipyridine (bpy) (1), 1,10-phenanthroline (phen) (2), 1,4,8,9-tetraazatriphenylene (tatp) (3), dipyrido[3,2-a:2',3'-c]phenazine (dppz) (4), or benzo[i]dipyrido[3,2-a:2',3'-c]phenazine (dppn) (5), respectively) were synthesized. The influence of π-conjugation of the ancillary ligands (N^N) on the photophysical properties of the complexes was investigated by spectroscopic methods and simulated by density functional theory (DFT) and time-dependent DFT. Their ground-state absorption spectra were characterized by intense absorption bands below 350 nm (ligand L localized 1π,π* transitions) and a featureless band centered at ∼410 nm (intraligand charge transfer (1ILCT)/1π,π* transitions with minor contribution from metal-to-ligand charge transfer (1MLCT) transition). For complexes 4 and 5 with dppz and dppn ligands, respectively, broad but very weak absorption (ε < 800 M-1 cm-1) was present from 600 to 850 nm, likely emanating from the spin-forbidden transitions to the triplet excited states. All five complexes showed red-orange phosphorescence at room temperature in CH2Cl2 solution with decreased lifetimes and emission quantum yields, as the π-conjugation of the ancillary ligands increased. Transient absorption (TA) profiles were probed in acetonitrile solutions at room temperature for all of the complexes. Except for complex 5 (which showed dppn-localized 3π,π* absorption with a long lifetime of 41.2 μs), complexes 1-4 displayed similar TA spectral features but with much shorter triplet lifetimes (1-2 μs). Reverse saturable absorption (RSA) was demonstrated for the complexes at 532 nm using 4.1 ns laser pulses, and the strength of RSA decreased in the order: 2 ≥ 1 ≈ 5 > 3 > 4. Complex 5 is particularly attractive as a broadband reverse saturable absorber due to its wide optical window (430-850 nm) and long-lived triplet lifetime in addition to its strong RSA at 532 nm. Complexes 1-5 were also probed as photosensitizing agents for in vitro photodynamic therapy (PDT). Most of them showed a PDT effect, and 5 emerged as the most potent complex with red light (EC50 = 10 μM) and was highly photoselective for melanoma cells (selectivity factor, SF = 13). Complexes 1-5 were readily taken up by cells and tracked by their intracellular luminescence before and after a light treatment. Diagnostic intracellular luminescence increased with increased π-conjugation of the ancillary N^N ligands despite diminishing cell-free phosphorescence in that order. All of the complexes penetrated the nucleus and caused DNA condensation in cell-free conditions in a concentration-dependent manner, which was not influenced by the identity of N^N ligands. Although the mechanism for photobiological activity was not established, complexes 1-5 were shown to exhibit potential as theranostic agents. Together the RSA and PDT studies indicate that developing new agents with long intrinsic triplet lifetimes, high yields for triplet formation, and broad ground-state absorption to near-infrared (NIR) in tandem is a viable approach to identifying promising agents for these applications.
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Affiliation(s)
- Li Wang
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
| | - Huimin Yin
- Department of Chemistry, Acadia University , 6 University Avenue, Wolfville, NS B4P 2R6, Canada
| | - Mohammed A Jabed
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
| | - Marc Hetu
- Department of Chemistry, Acadia University , 6 University Avenue, Wolfville, NS B4P 2R6, Canada
| | - Chengzhe Wang
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
| | - Susan Monro
- Department of Chemistry, Acadia University , 6 University Avenue, Wolfville, NS B4P 2R6, Canada
| | - Xiaolin Zhu
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
| | - Svetlana Kilina
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
| | - Sherri A McFarland
- Department of Chemistry, Acadia University , 6 University Avenue, Wolfville, NS B4P 2R6, Canada.,Department of Chemistry and Biochemistry, University of North Carolina at Greensboro , Greensboro, North Carolina 27402-6170, United States
| | - Wenfang Sun
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
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29
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Zhu X, Lystrom L, Kilina S, Sun W. Tuning the Photophysics and Reverse Saturable Absorption of Heteroleptic Cationic Iridium(III) Complexes via Substituents on the 6,6′-Bis(fluoren-2-yl)-2,2′-biquinoline Ligand. Inorg Chem 2016; 55:11908-11919. [DOI: 10.1021/acs.inorgchem.6b02028] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xiaolin Zhu
- Department
of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
| | - Levi Lystrom
- Department
of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
| | - Svetlana Kilina
- Department
of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
| | - Wenfang Sun
- Department
of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
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30
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Mukhopadhyay S, Singh RS, Biswas A, Maiti B, Pandey DS. Molecular and Nanoaggregation in Cyclometalated Iridium(III) Complexes through Structural Modification. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201600563] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Sujay Mukhopadhyay
- Department of Chemistry; Institute of Science; Banaras Hindu University; 221005 Varanasi U.P. India
| | - Roop Shikha Singh
- Department of Chemistry; Institute of Science; Banaras Hindu University; 221005 Varanasi U.P. India
| | - Arnab Biswas
- Department of Chemistry; Institute of Science; Banaras Hindu University; 221005 Varanasi U.P. India
| | - Biswajit Maiti
- Department of Chemistry; Institute of Science; Banaras Hindu University; 221005 Varanasi U.P. India
| | - Daya Shankar Pandey
- Department of Chemistry; Institute of Science; Banaras Hindu University; 221005 Varanasi U.P. India
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31
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Li Z, Li H, Gifford BJ, Peiris WDN, Kilina S, Sun W. Synthesis, photophysics, and reverse saturable absorption of 7-(benzothiazol-2-yl)-9,9-di(2-ethylhexyl)-9H-fluoren-2-yl tethered [Ir(bpy)(ppy)2]PF6 and Ir(ppy)3 complexes (bpy = 2,2′-bipyridine, ppy = 2-phenylpyridine). RSC Adv 2016. [DOI: 10.1039/c5ra20084a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Both the charges and benzothiazolylfluorenyl pendant on the 2-phenylpyridine ligand influence the photophysics and reverse saturable absorption of Ir(iii) complexes.
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Affiliation(s)
- Zhongjing Li
- Department of Chemistry and Biochemistry
- North Dakota State University
- Fargo
- USA
| | - Hui Li
- Department of Chemistry and Biochemistry
- North Dakota State University
- Fargo
- USA
| | - Brendan J. Gifford
- Department of Chemistry and Biochemistry
- North Dakota State University
- Fargo
- USA
| | | | - Svetlana Kilina
- Department of Chemistry and Biochemistry
- North Dakota State University
- Fargo
- USA
| | - Wenfang Sun
- Department of Chemistry and Biochemistry
- North Dakota State University
- Fargo
- USA
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32
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Howarth AJ, Majewski MB, Brown CM, Lelj F, Wolf MO, Patrick BO. Emissive Ir(III) complexes bearing thienylamido groups on a 1,10-phenanthroline scaffold. Dalton Trans 2015; 44:16272-9. [PMID: 26278384 DOI: 10.1039/c5dt02691a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis, structures and photophysical properties of a series of bis-cyclometallated Ir(iii) complexes bearing phenylpyrazole (ppz) cyclometallating ligands and phenanthroline-based ancillary ligands containing thienyl- and bithienylamido groups are reported. All complexes are emissive in solution, while in PMMA films strong emission is observed from the thienylamido substituted complex with no emission from the bithienylamido complex. The bithienylamido substituted complex has an excited state lifetime which is significantly longer than the emission lifetime, attributed to the population of non-equilibrated (3)MLCT and (3)LC states in this complex. This represents a rare example of this unusual excited state behaviour. DFT calculations show that the emitting (3)MLCT state and the dark (3)LC state on bithiophene are close in energy and that a large change in the triplet state geometry occurs upon excitation that effectively lowers the energy of the (3)MLCT state below that of the dark (3)LC state. The low quantum yield of the bithienylamido complex is attributed to a structural rearrangement upon relaxation back to the ground state, opening a non-radiative decay pathway.
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Affiliation(s)
- Ashlee J Howarth
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6 T 1Z1, Canada.
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33
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Liu R, Dandu N, McCleese C, Li Y, Lu T, Li H, Yost D, Wang C, Kilina S, Burda C, Sun W. Influence of a Naphthaldiimide Substituent at the Diimine Ligand on the Photophysics and Reverse Saturable Absorption of Pt
II
Diimine Complexes and Cationic Ir
III
Complexes. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500882] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Rui Liu
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108‐6050, USA, http://https://www.ndsu.edu/chemistry/people/faculty/sun.html
- Department of Applied Chemistry, College of Sciences, Nanjing Tech University, Nanjing 211816, P.R. China
| | - Naveen Dandu
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108‐6050, USA, http://https://www.ndsu.edu/chemistry/people/faculty/sun.html
| | - Christopher McCleese
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - Yuhao Li
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108‐6050, USA, http://https://www.ndsu.edu/chemistry/people/faculty/sun.html
| | - Taotao Lu
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108‐6050, USA, http://https://www.ndsu.edu/chemistry/people/faculty/sun.html
| | - Hui Li
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108‐6050, USA, http://https://www.ndsu.edu/chemistry/people/faculty/sun.html
| | - Dillon Yost
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108‐6050, USA, http://https://www.ndsu.edu/chemistry/people/faculty/sun.html
| | - Chengzhe Wang
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108‐6050, USA, http://https://www.ndsu.edu/chemistry/people/faculty/sun.html
| | - Svetlana Kilina
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108‐6050, USA, http://https://www.ndsu.edu/chemistry/people/faculty/sun.html
| | - Clemens Burda
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - Wenfang Sun
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108‐6050, USA, http://https://www.ndsu.edu/chemistry/people/faculty/sun.html
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34
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Pei C, Cui P, McCleese C, Kilina S, Burda C, Sun W. Heteroleptic cationic iridium(III) complexes bearing naphthalimidyl substituents: synthesis, photophysics and reverse saturable absorption. Dalton Trans 2015; 44:2176-90. [PMID: 25512315 DOI: 10.1039/c4dt02384f] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Three heteroleptic cationic iridium(iii) complexes containing a cyclometalating 2-[3-(7-naphthalimidylfluoren-2'-yl)phenyl]pyridine ligand and different diimine (N^N) ligands (N^N = 2,2'-bipyridine (bpy, ), 1,10-phenanthroline (phen, ), and 5,5'-bis[7-(benzothiazol-2'-yl)fluoren-2'-yl]-2,2'-bipyridine (BTF-bpy, )) were synthesized and characterized. The photophysics of these complexes was systematically investigated via spectroscopic methods and by time-dependent density functional theory (TDDFT). All complexes possess a very weak charge-transfer tail at ca. 450-570 nm; and two intense absorption bands in the region of 290-350 nm and 350-450 nm, respectively. The emission of in CH2Cl2 emanates predominantly from the C^N ligand-localized (3)π,π* state. These emitting excited states also give rise to broadband triplet excited-state absorption in the visible to the near-IR region (i.e. 420-800 nm for and , and 460-800 nm for ). The kinetics of fs transient absorption (TA) reveals that the lowest singlet excited-state lifetimes of these complexes vary from 1.43 ps to 142 ps. The stronger excited-state absorption of compared to their respective ground-state absorption in the visible spectral range leads to strong reverse saturable absorption (RSA) at 532 nm for ns laser pulses. The trend of transmission signal decrease follows > > . Extending the π-conjugation of the N^N ligand increases the strength of RSA. In addition, the naphthalimidyl (NI) substitution at the cyclometalating ligand dramatically increases the triplet excited-state lifetimes and broadens the triplet excited-state absorption to the NIR region compared to the respective Ir(iii) complexes with a benzothiazolyl substituent on the cyclometalating ligand.
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Affiliation(s)
- Chengkui Pei
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, USA.
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35
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Howarth AJ, Davies DL, Lelj F, Wolf MO, Patrick BO. Tuning the emission lifetime in bis-cyclometalated iridium(III) complexes bearing iminopyrene ligands. Inorg Chem 2014; 53:11882-9. [PMID: 25347609 DOI: 10.1021/ic501032t] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Bis-cyclometalated Ir(III) complexes with the general formula Ir(ppz)2(X^NPyrene), where ppz = 1-phenylpyrazole and X^NPyrene is a bidentate chelate with X = N or O, are reported. Modifications on the ancillary ligand containing pyrene drastically affect the emission lifetimes observed (0.329 to 104 μs). Extended emission lifetimes in these complexes compared to model complexes result from reversible electronic energy transfer or the observation of dual emission containing along-lived pyrene ligand-centered triplet ((3)LC) component. A combination of steady-state and time-resolved spectroscopic techniques are used to observe reversible electronic energy transfer in solution between the iridium core and pyrene moiety in the complex [Ir(ppz)2(NMe^NCH2Pyr)][PF6] (2), where NMe^NCH2Pyr = N-(pyren-1-ylmethyl)-1-(pyridin-2-yl)ethaneimine. Studies on [Ir(ppz)2(NMe^NCH2Pyr)][PF6] in a poly(methyl methacrylate) (PMMA) film reveal that reversible energy transfer is no longer effective, and instead, dual emission with a long-lived (3)LC component from pyrene is observed. Dual emission is observed in additional cyclometalated iridium complexes bearing pyrene-containing ancillary ligands N^NPyrene and O^NPyrene when the complexes are dispersed in a PMMA film.
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Affiliation(s)
- Ashlee J Howarth
- Department of Chemistry, University of British Columbia , Vancouver, British Columbia V6T 1Z1, Canada
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36
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Denisov S, Cudré Y, Verwilst P, Jonusauskas G, Marín-Suárez M, Fernández-Sánchez JF, Baranoff E, McClenaghan ND. Direct observation of reversible electronic energy transfer involving an iridium center. Inorg Chem 2014; 53:2677-82. [PMID: 24555716 PMCID: PMC3950932 DOI: 10.1021/ic4030712] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Indexed: 01/06/2023]
Abstract
A cyclometalated iridium complex is reported where the core complex comprises naphthylpyridine as the main ligand and the ancillary 2,2'-bipyridine ligand is attached to a pyrene unit by a short alkyl bridge. To obtain the complex with satisfactory purity, it was necessary to modify the standard synthesis (direct reaction of the ancillary ligand with the chloro-bridged iridium dimer) to a method harnessing an intermediate tetramethylheptanolate-based complex, which was subjected to acid-promoted removal of the ancillary ligand and subsequent complexation. The photophysical behavior of the bichromophoric complex and a model complex without the pendant pyrene were studied using steady-state and time-resolved spectroscopies. Reversible electronic energy transfer (REET) is demonstrated, uniquely with an emissive cyclometalated iridium center and an adjacent organic chromophore. After excited-state equilibration is established (5 ns) as a result of REET, extremely long luminescence lifetimes of up to 225 μs result, compared to 8.3 μs for the model complex, without diminishing the emission quantum yield. As a result, remarkably high oxygen sensitivity is observed in both solution and polymeric matrices.
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Affiliation(s)
- Sergey
A. Denisov
- Université
Bordeaux/CNRS, ISM, 351
cours de la Libération, 33405 Talence Cedex, France
- Université
Bordeaux/CNRS, LOMA, 351 cours de la Libération, 33405 Talence Cedex, France
| | - Yanouk Cudré
- School of Chemistry, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Peter Verwilst
- Université
Bordeaux/CNRS, ISM, 351
cours de la Libération, 33405 Talence Cedex, France
| | - Gediminas Jonusauskas
- Université
Bordeaux/CNRS, LOMA, 351 cours de la Libération, 33405 Talence Cedex, France
| | - Marta Marín-Suárez
- Department of Analytical Chemistry, Faculty
of Sciences, University of Granada, Avenida Fuentenueva s/n, 18071 Granada, Spain
| | | | - Etienne Baranoff
- School of Chemistry, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Nathan D. McClenaghan
- Université
Bordeaux/CNRS, ISM, 351
cours de la Libération, 33405 Talence Cedex, France
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37
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Li Y, Dandu N, Liu R, Kilina S, Sun W. Synthesis and photophysics of reverse saturable absorbing heteroleptic iridium(iii) complexes bearing 2-(7-R-fluoren-2′-yl)pyridine ligands. Dalton Trans 2014; 43:1724-35. [DOI: 10.1039/c3dt52184b] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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