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Li TY, Zheng SJ, Djurovich PI, Thompson ME. Two-Coordinate Thermally Activated Delayed Fluorescence Coinage Metal Complexes: Molecular Design, Photophysical Characters, and Device Application. Chem Rev 2024; 124:4332-4392. [PMID: 38546341 DOI: 10.1021/acs.chemrev.3c00761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Since the emergence of the first green light emission from a fluorescent thin-film organic light emitting diode (OLED) in the mid-1980s, a global consumer market for OLED displays has flourished over the past few decades. This growth can primarily be attributed to the development of noble metal phosphorescent emitters that facilitated remarkable gains in electrical conversion efficiency, a broadened color gamut, and vibrant image quality for OLED displays. Despite these achievements, the limited abundance of noble metals in the Earth's crust has spurred ongoing efforts to discover cost-effective electroluminescent materials. One particularly promising avenue is the exploration of thermally activated delayed fluorescence (TADF), a mechanism with the potential to fully harness excitons in OLEDs. Recently, investigations have unveiled TADF in a series of two-coordinate coinage metal (Cu, Ag, and Au) complexes. These organometallic TADF materials exhibit distinctive behavior in comparison to their organic counterparts. They offer benefits such as tunable emissive colors, short TADF emission lifetimes, high luminescent quantum yields, and reasonable stability. Impressively, both vacuum-deposited and solution-processed OLEDs incorporating these materials have achieved outstanding performance. This review encompasses various facets on two-coordinate TADF coinage metal complexes, including molecular design, photophysical characterizations, elucidation of structure-property relationships, and OLED applications.
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Affiliation(s)
- Tian-Yi Li
- Department of Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Shu-Jia Zheng
- Department of Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Peter I Djurovich
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Mark E Thompson
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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2
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Meyer M, Prescimone A, Constable EC, Housecroft CE. Introducing sterically demanding substituents and π-π-interactions into [Cu(P^P)(N^N)] + complexes. Dalton Trans 2024; 53:5453-5465. [PMID: 38414289 DOI: 10.1039/d4dt00276h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
A series of ten N^N chelating ligands based on a 2,2'-bipyridine (bpy) metal-binding domain and featuring sterically hindering substituents in the 6- and 6,6'-positions has been synthesized and characterized. The ligands have been incorporated into a family of 15 heteroleptic complexes of type [Cu(P^P)(N^N)][PF6] where P^P is the wide bite-angle bisphosphane ligand bis(2(diphenylphosphanyl)phenyl)ether (POP) or (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane) (xantphos). Substituents in several of the N^N ligands ligands possess phenyl rings remotely tethered to enable intra- and intermolecular π-π-interactions in the [Cu(P^P)(N^N)]+ cations. Single crystal X-ray structures of 12 complexes are reported. The effects of the functional groups in the bpy ligand on the photophysical properties of the complexes have been studied; solid-state emission maxima range from 518 to 567 nm. Values of the solid-state photoluminescence quantum yields (PLQYs) of the [Cu(P^P)(N^N)][PF6] compounds respond to the nature of the N^N ligand. In general, we observed that the [Cu(P^P)(N^N)]+ complexes containing 6,6'-disubstituted complexes with phenyl moieties connected via a CH2CH2 or CH2CH2CH2 spacer to the bpy domain have the highest values of PLQY. The most significant compounds are [Cu(POP)((2-PhEt)2bpy)][PF6] (PLQY = 67%) and [Cu(POP)((3-PhPr)2bpy)][PF6] (PLQY = 72%) where (2-PhEt)2bpy = 6,6'-bis(2-phenylethyl)-2,2'-bipyridine and (3-PhPr)2bpy = 6,6'-bis(3-phenylpropyl)-2,2'-bipyridine. These PLQY values are among the best performing previously reported families of [Cu(P^P)(N^N)][PF6] compounds.
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Affiliation(s)
- Marco Meyer
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4058 Basel, Switzerland.
| | - Alessandro Prescimone
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4058 Basel, Switzerland.
| | - Edwin C Constable
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4058 Basel, Switzerland.
| | - Catherine E Housecroft
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, 4058 Basel, Switzerland.
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3
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Wang R, Liu S, Chen H, Wu X, Ding H, Xu S, Wu Y, Wang Y, Zhao F. Synthesis and luminescence properties of the four-coordinate N-heterocyclic carbene (NHC) copper(I) complexes with different bisphosphine ligands. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2023.135504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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4
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Beaudelot J, Oger S, Peruško S, Phan TA, Teunens T, Moucheron C, Evano G. Photoactive Copper Complexes: Properties and Applications. Chem Rev 2022; 122:16365-16609. [PMID: 36350324 DOI: 10.1021/acs.chemrev.2c00033] [Citation(s) in RCA: 64] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Photocatalyzed and photosensitized chemical processes have seen growing interest recently and have become among the most active areas of chemical research, notably due to their applications in fields such as medicine, chemical synthesis, material science or environmental chemistry. Among all homogeneous catalytic systems reported to date, photoactive copper(I) complexes have been shown to be especially attractive, not only as alternative to noble metal complexes, and have been extensively studied and utilized recently. They are at the core of this review article which is divided into two main sections. The first one focuses on an exhaustive and comprehensive overview of the structural, photophysical and electrochemical properties of mononuclear copper(I) complexes, typical examples highlighting the most critical structural parameters and their impact on the properties being presented to enlighten future design of photoactive copper(I) complexes. The second section is devoted to their main areas of application (photoredox catalysis of organic reactions and polymerization, hydrogen production, photoreduction of carbon dioxide and dye-sensitized solar cells), illustrating their progression from early systems to the current state-of-the-art and showcasing how some limitations of photoactive copper(I) complexes can be overcome with their high versatility.
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Affiliation(s)
- Jérôme Beaudelot
- Laboratoire de Chimie Organique, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/06, 1050Brussels, Belgium.,Laboratoire de Chimie Organique et Photochimie, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/08, 1050Brussels, Belgium
| | - Samuel Oger
- Laboratoire de Chimie Organique, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/06, 1050Brussels, Belgium
| | - Stefano Peruško
- Laboratoire de Chimie Organique, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/06, 1050Brussels, Belgium.,Organic Synthesis Division, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, 2020Antwerp, Belgium
| | - Tuan-Anh Phan
- Laboratoire de Chimie Organique et Photochimie, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/08, 1050Brussels, Belgium
| | - Titouan Teunens
- Laboratoire de Chimie Organique et Photochimie, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/08, 1050Brussels, Belgium.,Laboratoire de Chimie des Matériaux Nouveaux, Université de Mons, Place du Parc 20, 7000Mons, Belgium
| | - Cécile Moucheron
- Laboratoire de Chimie Organique et Photochimie, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/08, 1050Brussels, Belgium
| | - Gwilherm Evano
- Laboratoire de Chimie Organique, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/06, 1050Brussels, Belgium
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5
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Hu FZ, Zhang L, Jin GY, Sun ZZ, Wang G, Han HL, Li ZF, Yang YP, Jin QH, Zhang F. Synthesis, spectral properties and terahertz time domain spectroscopy of two copper(I) complexes based on bisphosphine and bisazo ligands. J COORD CHEM 2022. [DOI: 10.1080/00958972.2022.2070486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Fu-Zhen Hu
- Department of Chemistry, Capital Normal University, Beijing, China
| | - Lan Zhang
- Department of Chemistry, Capital Normal University, Beijing, China
| | - Guan-Yu Jin
- Department of Chemistry, Capital Normal University, Beijing, China
| | - Zhen-Zhou Sun
- Department of Chemistry, Capital Normal University, Beijing, China
| | - Guo Wang
- Department of Chemistry, Capital Normal University, Beijing, China
| | - Hong-Liang Han
- Department of Chemistry, Capital Normal University, Beijing, China
| | - Zhong-Feng Li
- Department of Chemistry, Capital Normal University, Beijing, China
| | - Yu-Ping Yang
- School of Science, Minzu University of China, Beijing, China
| | - Qiong-Hua Jin
- Department of Chemistry, Capital Normal University, Beijing, China
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, China
| | - Fan Zhang
- Department of Chemistry, Capital Normal University, Beijing, China
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Paderina A, Melnikov A, Slavova S, Sizov V, Gurzhiy V, Petrovskii S, Luginin M, Levin O, Koshevoy I, Grachova E. The Tail Wags the Dog: The Far Periphery of the Coordination Environment Manipulates the Photophysical Properties of Heteroleptic Cu(I) Complexes. Molecules 2022; 27:2250. [PMID: 35408648 PMCID: PMC9000333 DOI: 10.3390/molecules27072250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/26/2022] [Accepted: 03/28/2022] [Indexed: 11/16/2022] Open
Abstract
In this work we show, using the example of a series of [Cu(Xantphos)(N^N)]+ complexes (N^N being substituted 5-phenyl-bipyridine) with different peripheral N^N ligands, that substituents distant from the main action zone can have a significant effect on the physicochemical properties of the system. By using the C≡C bond on the periphery of the coordination environment, three hybrid molecular systems with -Si(CH3)3, -Au(PR3), and -C2HN3(CH2)C10H7 fragments were produced. The Cu(I) complexes thus obtained demonstrate complicated emission behaviour, which was investigated by spectroscopic, electrochemical, and computational methods in order to understand the mechanism of energy transfer. It was found that the -Si(CH3)3 fragment connected to the peripheral C≡C bond changes luminescence to long-lived intra-ligand phosphorescence, in contrast to MLCT phosphorescence or TADF. The obtained results can be used for the design of new materials based on Cu(I) complexes with controlled optoelectronic properties on the molecular level, as well as for the production of hybrid systems.
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Affiliation(s)
- Aleksandra Paderina
- Institute of Chemistry, St. Petersburg University, Universitetskii pr. 26, 198504 St. Petersburg, Russia; (A.P.); (V.S.); (S.P.); (M.L.); (O.L.)
| | - Alexey Melnikov
- Centre for Nano- and Biotechnologies, Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia;
| | - Sofia Slavova
- Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria;
| | - Vladimir Sizov
- Institute of Chemistry, St. Petersburg University, Universitetskii pr. 26, 198504 St. Petersburg, Russia; (A.P.); (V.S.); (S.P.); (M.L.); (O.L.)
| | - Vladislav Gurzhiy
- Institute of Earth Sciences, St. Petersburg University, 199034 St. Petersburg, Russia;
| | - Stanislav Petrovskii
- Institute of Chemistry, St. Petersburg University, Universitetskii pr. 26, 198504 St. Petersburg, Russia; (A.P.); (V.S.); (S.P.); (M.L.); (O.L.)
| | - Maksim Luginin
- Institute of Chemistry, St. Petersburg University, Universitetskii pr. 26, 198504 St. Petersburg, Russia; (A.P.); (V.S.); (S.P.); (M.L.); (O.L.)
| | - Oleg Levin
- Institute of Chemistry, St. Petersburg University, Universitetskii pr. 26, 198504 St. Petersburg, Russia; (A.P.); (V.S.); (S.P.); (M.L.); (O.L.)
| | - Igor Koshevoy
- Department of Chemistry, University of Eastern Finland, 80101 Joensuu, Finland;
| | - Elena Grachova
- Institute of Chemistry, St. Petersburg University, Universitetskii pr. 26, 198504 St. Petersburg, Russia; (A.P.); (V.S.); (S.P.); (M.L.); (O.L.)
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7
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Housecroft CE, Constable EC. TADF: Enabling luminescent copper(i) coordination compounds for light-emitting electrochemical cells. JOURNAL OF MATERIALS CHEMISTRY. C 2022; 10:4456-4482. [PMID: 35433007 PMCID: PMC8944257 DOI: 10.1039/d1tc04028f] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/11/2021] [Indexed: 05/07/2023]
Abstract
The last decade has seen a surge of interest in the emissive behaviour of copper(i) coordination compounds, both neutral compounds that may have applications in organic light-emitting doides (OLEDs) and copper-based ionic transition metal complexes (Cu-iTMCs) with potential use in light-emitting electrochemical cells (LECs). One of the most exciting features of copper(i) coordination compounds is their possibility to exhibit thermally activated delayed fluorescence (TADF) in which the energy separation of the excited singlet (S1) and excited triplet (T1) states is very small, permitting intersystem crossing (ISC) and reverse intersystem crossing (RISC) to occur at room temperature without the requirement for the large spin-orbit coupling inferred by the presence of a heavy metal such as iridium. In this review, we focus mainly in Cu-iTMCs, and illustrate how the field of luminescent compounds and those exhibiting TADF has developed. Copper(i) coordination compounds that class as Cu-iTMCs include those containing four-coordinate [Cu(P^P)(N^N)]+ (P^P = large-bite angle bisphosphane, and N^N is typically a diimine), [Cu(P)2(N^N)]+ (P = monodentate phosphane ligand), [Cu(P)(tripodal-N3)]+, [Cu(P)(N^N)(N)]+ (N = monodentate N-donor ligand), [Cu(P^P)(N^S)]+ (N^S = chelating N,S-donor ligand), [Cu(P^P)(P^S)]+ (P^S = chelating P,S-donor ligand), [Cu(P^P)(NHC)]+ (NHC = N-heterocyclic carbene) coordination domains, dinuclear complexes with P^P and N^N ligands, three-coordinate [Cu(N^N)(NHC)]+ and two-coordinate [Cu(N)(NHC)]+ complexes. We pay particular attention to solid-state structural features, e.g. π-stacking interactions and other inter-ligand interactions, which may impact on photoluminescence quantum yields. Where emissive Cu-iTMCs have been tested in LECs, we detail the device architectures, and this emphasizes differences which make it difficult to compare LEC performances from different investigations.
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Affiliation(s)
- Catherine E Housecroft
- Department of Chemistry, University of Basel Mattenstrasse 24a, BPR 1096 4058-Basel Switzerland
| | - Edwin C Constable
- Department of Chemistry, University of Basel Mattenstrasse 24a, BPR 1096 4058-Basel Switzerland
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8
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Nohara I, Wegeberg C, Devereux M, Prescimone A, Housecroft CE, Constable EC. The surprising effects of sulfur: achieving long excited-state lifetimes in heteroleptic copper(i) emitters. JOURNAL OF MATERIALS CHEMISTRY. C 2022; 10:3089-3102. [PMID: 35340713 PMCID: PMC8870442 DOI: 10.1039/d1tc05591g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
A series of heteroleptic [Cu(N^N)(P^P)][PF6] complexes is reported in which N^N is a di(methylsulfanyl)-1,10-phenanthroline (2,9-, 3,8- or 4,7-(MeS)2phen) or di(methoxy)-1,10-phenanthroline (2,9-, 3,8- or 4,7-(MeO)2phen) and P^P is bis(2-(diphenylphosphano)phenyl)ether (POP) or 4,5-bis(diphenylphosphano)-9,9-dimethylxanthene (xantphos). The effects of the different substituents are investigated through structural, electrochemical and photophysical studies and by using DFT and TD-DFT calculations. Introducing methylsulfanyl groups in the 2,9-, 3,8- or 4,7-positions of the phen domain alters the composition of the frontier molecular orbitals of the [Cu(N^N)(P^P)]+ complexes significantly, so that ligand-centred (LC) transitions become photophysically relevant with respect to metal-to-ligand charge transfer (MLCT). Within this series, [Cu(2,9-(MeS)2phen)(POP)][PF6] exhibits the highest photoluminescence quantum yield of 15% and the longest excited-state lifetime of 8.3 μs in solution. In the solid state and in frozen matrices at 77 K, the electronic effects of the methylsulfanyl or methoxy substituents are highlighted, thus resulting in luminescence lifetimes of 2 to 4.2 ms at 77 K with predominantly LC character for both the 3,8- and 4,7-(MeS)2phen containing complexes. The results of the investigation give new guidelines on how to influence the luminescence properties in [Cu(N^N)(P^P)]+ complexes which will aid in the development of new sustainable and efficient copper(i) emitters.
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Affiliation(s)
- Isaak Nohara
- Department of Chemistry, University of Basel, BPR 1096 Mattenstrasse 24a CH-4058 Basel Switzerland
| | - Christina Wegeberg
- Department of Chemistry, University of Basel, BPR 1096 Mattenstrasse 24a CH-4058 Basel Switzerland
- Department of Chemistry, University of Basel St Johanns-Ring 19 CH-4056 Basel Switzerland
| | - Mike Devereux
- Department of Chemistry, University of Basel Klingelbergstrasse 80 CH-4056 Basel Switzerland
| | - Alessandro Prescimone
- Department of Chemistry, University of Basel, BPR 1096 Mattenstrasse 24a CH-4058 Basel Switzerland
| | - Catherine E Housecroft
- Department of Chemistry, University of Basel, BPR 1096 Mattenstrasse 24a CH-4058 Basel Switzerland
| | - Edwin C Constable
- Department of Chemistry, University of Basel, BPR 1096 Mattenstrasse 24a CH-4058 Basel Switzerland
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9
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Schiff base-type copper(I) complexes exhibiting high molar extinction coefficients: Synthesis, characterization and DFT studies. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.131638] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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10
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Zheng D, Huang TH, Luo C, Tang J. Structural characterization, DFT studies and luminescent properties of dinuclear copper(I)-diimine complexes with the S-shape configurations. Inorganica Chim Acta 2022. [DOI: 10.1016/j.ica.2021.120639] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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11
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Argüello Cordero MA, Boden PJ, Rentschler M, Di Martino-Fumo P, Frey W, Yang Y, Gerhards M, Karnahl M, Lochbrunner S, Tschierlei S. Comprehensive Picture of the Excited State Dynamics of Cu(I)- and Ru(II)-Based Photosensitizers with Long-Lived Triplet States. Inorg Chem 2021; 61:214-226. [PMID: 34908410 DOI: 10.1021/acs.inorgchem.1c02771] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ru(II)- and Cu(I)-based photosensitizers featuring the recently developed biipo ligand (16H-benzo-[4',5']-isoquinolino-[2',1',:1,2]-imidazo-[4,5-f]-[1,10]-phenanthrolin-16-one) were comprehensively investigated by X-ray crystallography, electrochemistry, and especially several time-resolved spectroscopic methods covering all time scales from femto- to milliseconds. The analysis of the experimental results is supported by density functional theory (DFT) calculations. The biipo ligand consists of a coordinating 1,10-phenanthroline moiety fused with a 1,8-naphthalimide unit, which results in an extended π-system with an incorporated electron acceptor moiety. In a previous study, it was shown that this ligand enabled a Ru(II) complex that is an efficient singlet oxygen producer and of potential use for other light-driven applications due to its long emission lifetime. The goal of our here presented research is to provide a full spectroscopic picture of the processes that follow optical excitation. Interestingly, the Ru(II) and Cu(I) complexes differ in their characteristics even though the lowest electronically excited states involve in both cases the biipo ligand. The combined spectroscopic results indicate that an emissive 3MLCT state and a rather dark 3LC state are populated, each to some extent. For the Cu(I) complex, most of the excited population ends up in the 3LC state with an extraordinary lifetime of 439 μs in the solid state at 20 K, while a significant population of the 3MLCT state causes luminescence for the Ru(II) complex. Hence, there is a balance between these two states, which can be tuned by altering the metal center or even by thermal energy, as suggested by the temperature-dependent experiments.
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Affiliation(s)
- Miguel A Argüello Cordero
- Institute for Physics and Department of Life, Light and Matter, University of Rostock, 18051 Rostock, Germany
| | - Pit Jean Boden
- Chemistry Department and Research Center Optimas, TU Kaiserslautern, Erwin-Schrödinger-Straße 52, 67663 Kaiserslautern, Germany
| | - Martin Rentschler
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany.,Department of Energy Conversion, Institute of Physical and Theoretical Chemistry, Technische Universität Braunschweig, Gaußstraße 17, 38106 Braunschweig, Germany
| | - Patrick Di Martino-Fumo
- Chemistry Department and Research Center Optimas, TU Kaiserslautern, Erwin-Schrödinger-Straße 52, 67663 Kaiserslautern, Germany
| | - Wolfgang Frey
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Yingya Yang
- Department of Energy Conversion, Institute of Physical and Theoretical Chemistry, Technische Universität Braunschweig, Gaußstraße 17, 38106 Braunschweig, Germany
| | - Markus Gerhards
- Chemistry Department and Research Center Optimas, TU Kaiserslautern, Erwin-Schrödinger-Straße 52, 67663 Kaiserslautern, Germany
| | - Michael Karnahl
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany.,Department of Energy Conversion, Institute of Physical and Theoretical Chemistry, Technische Universität Braunschweig, Gaußstraße 17, 38106 Braunschweig, Germany
| | - Stefan Lochbrunner
- Institute for Physics and Department of Life, Light and Matter, University of Rostock, 18051 Rostock, Germany
| | - Stefanie Tschierlei
- Department of Energy Conversion, Institute of Physical and Theoretical Chemistry, Technische Universität Braunschweig, Gaußstraße 17, 38106 Braunschweig, Germany
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12
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Li C, Mackenzie CFR, Said SA, Pal AK, Haghighatbin MA, Babaei A, Sessolo M, Cordes DB, Slawin AMZ, Kamer PCJ, Bolink HJ, Hogan CF, Zysman-Colman E. Wide-Bite-Angle Diphosphine Ligands in Thermally Activated Delayed Fluorescent Copper(I) Complexes: Impact on the Performance of Electroluminescence Applications. Inorg Chem 2021; 60:10323-10339. [PMID: 34197094 DOI: 10.1021/acs.inorgchem.1c00804] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report a series of seven cationic heteroleptic copper(I) complexes of the form [Cu(P^P)(dmphen)]BF4, where dmphen is 2,9-dimethyl-1,10-phenanthroline and P^P is a diphosphine chelate, in which the effect of the bite angle of the diphosphine ligand on the photophysical properties of the complexes was studied. Several of the complexes exhibit moderately high photoluminescence quantum yields in the solid state, with ΦPL of up to 35%, and in solution, with ΦPL of up to 98%. We were able to correlate the powder photoluminescence quantum yields with the % Vbur of the P^P ligand. The most emissive complexes were used to fabricate both organic light-emitting diodes and light-emitting electrochemical cells (LECs), both of which showed moderate performance. Compared to the benchmark copper(I)-based LECs, [Cu(dnbp)(DPEPhos)]+ (maximum external quantum efficiency, EQEmax = 16%), complex 3 (EQEmax = 1.85%) showed a much longer device lifetime (t1/2 = 1.25 h and >16.5 h for [Cu(dnbp)(DPEPhos)]+ and complex 3, respectively). The electrochemiluminescence (ECL) properties of several complexes were also studied, which, to the best of our knowledge, constitutes the first ECL study for heteroleptic copper(I) complexes. Notably, complexes exhibiting more reversible electrochemistry were associated with higher annihilation ECL as well as better performance in a LEC.
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Affiliation(s)
- Chenfei Li
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, U.K
| | - Campbell F R Mackenzie
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, U.K
| | - Said A Said
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, U.K
| | - Amlan K Pal
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, U.K.,Department of Chemistry, Indian Institute of Technology Jammu, Jagti Campus, Nagrota Bypass Road, Jammu, Jammu and Kashmir 181221, India
| | - Mohammad A Haghighatbin
- Department of Chemistry & Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Azin Babaei
- Instituto de Ciencia Molecular, Universidad de Valencia, Paterna 46980, Spain
| | - Michele Sessolo
- Instituto de Ciencia Molecular, Universidad de Valencia, Paterna 46980, Spain
| | - David B Cordes
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, U.K
| | - Alexandra M Z Slawin
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, U.K
| | - Paul C J Kamer
- Leibniz Institute for Catalysis, Albert-Einstein-Strasse 29a, Rostock 18059, Germany
| | - Henk J Bolink
- Instituto de Ciencia Molecular, Universidad de Valencia, Paterna 46980, Spain
| | - Conor F Hogan
- Department of Chemistry & Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Eli Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, U.K
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13
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Savchuk MI, Kopchuk DS, Taniya OS, Nikonov IL, Egorov IN, Santra S, Zyryanov GV, Chupakhin ON, Charushin VN. 5-Aryl-6-arylthio-2,2'-bipyridine and 6-Arylthio-2,5-diarylpyridine Fluorophores: Pot, Atom, Step Economic (PASE) Synthesis and Photophysical Studies. J Fluoresc 2021; 31:1099-1111. [PMID: 33966136 DOI: 10.1007/s10895-021-02714-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 03/03/2021] [Indexed: 11/29/2022]
Abstract
A PASE (pot, step, atom, economic) synthetic approach to 5-aryl-6-arylthio-2,2'-bipyridine and 6-arylthio-2,5-diarylpyridine ligands/fluorophores has been reported via SNH in 6-aryl-5H-1,2,4-triazines/aza-Diels-Alder reaction sequence. In this article, the "1,2,4-triazine" methodology was successfully used for the synthesis of C6-thiophenol-substituted (2,2'-bi)pyridines as it is well known that thio-substituted (bi)pyridines and their aza-analogs are of wide practical interest. The photophysical properties of the obtained compounds are studied and compared with those reported earlier for 6-substituted 2,2'-bipyridines. The influence of the nature of substituents in the 6-arylthio(bi)pyridine core on the photophysical properties is discussed. It was observed that the new compounds exhibited promising photophysical properties and could be considered as potential push-pull fluorophores. In addition, they demonstrated greater Stokes shift values compared to the previously described 6-H, 6-arylamino and 6-pentafluoro-2,2'-bipyridines and higher fluorescence quantum yields values compare to pentafluorophenyl-substituted 2,2'-bipyridines. Depending on a nature of (bi)pyridine fluorophore LE (locally excited) and/or ICT (intramolecular charge transfer) state were prevailing in emission spectra.
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Affiliation(s)
- Maria I Savchuk
- Ural Federal University, 19, Mira St, Yekaterinburg, Russian Federation, 620002.,Postovsky Institute of Organic Synthesis of RAS (Ural Division), 22/20, S. Kovalevskoy/Akademicheskaya St, Yekaterinburg, Russian Federation, 620990
| | - Dmitry S Kopchuk
- Ural Federal University, 19, Mira St, Yekaterinburg, Russian Federation, 620002.,Postovsky Institute of Organic Synthesis of RAS (Ural Division), 22/20, S. Kovalevskoy/Akademicheskaya St, Yekaterinburg, Russian Federation, 620990
| | - Olga S Taniya
- Ural Federal University, 19, Mira St, Yekaterinburg, Russian Federation, 620002.,Postovsky Institute of Organic Synthesis of RAS (Ural Division), 22/20, S. Kovalevskoy/Akademicheskaya St, Yekaterinburg, Russian Federation, 620990
| | - Igor L Nikonov
- Ural Federal University, 19, Mira St, Yekaterinburg, Russian Federation, 620002.,Postovsky Institute of Organic Synthesis of RAS (Ural Division), 22/20, S. Kovalevskoy/Akademicheskaya St, Yekaterinburg, Russian Federation, 620990
| | - Ilya N Egorov
- Ural Federal University, 19, Mira St, Yekaterinburg, Russian Federation, 620002
| | - Sougata Santra
- Ural Federal University, 19, Mira St, Yekaterinburg, Russian Federation, 620002.
| | - Grigory V Zyryanov
- Ural Federal University, 19, Mira St, Yekaterinburg, Russian Federation, 620002.,Postovsky Institute of Organic Synthesis of RAS (Ural Division), 22/20, S. Kovalevskoy/Akademicheskaya St, Yekaterinburg, Russian Federation, 620990
| | - Oleg N Chupakhin
- Ural Federal University, 19, Mira St, Yekaterinburg, Russian Federation, 620002.,Postovsky Institute of Organic Synthesis of RAS (Ural Division), 22/20, S. Kovalevskoy/Akademicheskaya St, Yekaterinburg, Russian Federation, 620990
| | - Valery N Charushin
- Ural Federal University, 19, Mira St, Yekaterinburg, Russian Federation, 620002.,Postovsky Institute of Organic Synthesis of RAS (Ural Division), 22/20, S. Kovalevskoy/Akademicheskaya St, Yekaterinburg, Russian Federation, 620990
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14
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Heteroleptic [Cu(P^P)(N^N)][PF6] Complexes: Effects of Isomer Switching from 2,2′-biquinoline to 1,1′-biisoquinoline. CRYSTALS 2021. [DOI: 10.3390/cryst11020185] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The preparation and characterization of [Cu(POP)(biq)][PF6] and [Cu(xantphos)(biq)][PF6] are reported (biq = 1,1′-biisoquinoline, POP = bis(2-(diphenylphosphanyl)phenyl)ether, and xantphos = (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane). The single crystal structure of [Cu(POP)(biq)][PF6] 0.5Et2O was determined and compared to that in three salts of [Cu(POP)(bq)]+ in which bq = 2,2′-biquinoline. The P–C–P angle is 114.456(19)o in [Cu(POP)(biq)]+ compared to a range of 118.29(3)–119.60(3)o [Cu(POP)(bq)]+. There is a change from an intra-POP PPh2-phenyl/(C6H4)2O-arene π-stacking in [Cu(POP)(biq)]+ to a π-stacking contact between the POP and bq ligands in [Cu(POP)(bq)]+. In solution and at ambient temperatures, the [Cu(POP)(biq)][PF6]+ and [Cu(xantphos)(biq)]+ cations undergo several concurrent dynamic processes, as evidenced in their multinuclear NMR spectra. The photophysical and electrochemical behaviors of the heteroleptic copper (I) complexes were investigated, and the effects of changing from bq to biq are described. Short Cu···O distances within the [Cu(POP)(biq)]+ and [Cu(xantphos)(biq)]+ cations may contribute to their very low photoluminescent quantum yields.
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15
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Velasco L, Llanos L, Levín P, Vega A, Yu J, Zhang X, Lemus L, Aravena D, Moonshiram D. Structure and excited-state dynamics of dimeric copper(i) photosensitizers investigated by time-resolved X-ray and optical transient absorption spectroscopy. Phys Chem Chem Phys 2021; 23:3656-3667. [PMID: 33527942 DOI: 10.1039/d0cp06080a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Time-resolved X-ray (tr-XAS) and optical transient absorption (OTA) spectroscopy in the picosecond time scale coupled with Density Functional theory (DFT) and X-ray absorption near-edge structure (XANES) calculations are applied to study three homoleptic Cu(i) dimeric chromophores with ethyl and longer propyl spacers, denoted as [Cu2(mphenet)2]Cl2 (C1), [Cu2(mphenet)2](ClO4)2 (C2) and [Cu2(mphenpr)2](ClO4)2 (C3) (where mphenet = 1,2-bis(9-methyl-1,10-phenanthrolin-2-yl)ethane and mphenpr = 1,3-bis(9-methyl-1,10-phenanthrolin-2-yl)propane). Tr-XAS analysis after light illumination at ∼ 100 ps illustrate the formation of a flattened triplet excited state in all 3 complexes. Optical transient absorption (OTA) analysis for C1 monitored in water and C2 and C3 measured in acetonitrile reveals distinct excited-state lifetimes of 169 ps, 670 ps and 1600 ps respectively. These differences are associated to changes in the solvent (comparing C1 and C2) and the flexibility of the ligand to adapt after Cu flattening upon excitation (C2 and C3). Our results are important for the improved structural dynamics of these types of Cu-based dimeric compounds, and can guide the integration of these chromophores into more complex solar energy conversion schemes.
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Affiliation(s)
- Lucía Velasco
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia), Calle Faraday, 9, 28049 Madrid, Spain.
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Huang TH, Wu TC, Zhao FZ, Zheng D, Luo C, Liang GM, Zhao B. Structures, electronic and luminescent properties of Cu(I)-quinoline complex at different temperatures and its application to red light-emitting diode. Inorganica Chim Acta 2021. [DOI: 10.1016/j.ica.2020.120008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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17
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Meyer M, Brunner F, Prescimone A, Constable EC, Housecroft CE. Desymmetrizing Heteroleptic [Cu(P^P)(N^N)][PF 6] Compounds: Effects on Structural and Photophysical Properties, and Solution Dynamic Behavior. Molecules 2020; 26:molecules26010125. [PMID: 33383919 PMCID: PMC7796056 DOI: 10.3390/molecules26010125] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 12/24/2020] [Accepted: 12/24/2020] [Indexed: 12/17/2022] Open
Abstract
The preparation, characterization and electrochemical and photophysical properties of a series of desymmetrized heteroleptic [Cu(P^P)(N^N)][PF6] compounds are reported. The complexes incorporate the chelating P^P ligands bis(2-(diphenylphosphanyl)phenyl)ether (POP) and (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane) (xantphos), and 6-substituted 2,2′-bipyridine (bpy) derivatives with functional groups attached by –(CH2)n– spacers: 6-(2,2′-bipyridin-6-yl)hexanoic acid (1), 6-(5-phenylpentyl)-2,2′-bipyridine (2) and 6-[2-(4-phenyl-1H-1,2,3,triazol-1-yl)ethyl]-2,2′-bipyridine (3). [Cu(POP)(1)][PF6], [Cu(xantphos)(1)][PF6], [Cu(POP)(2)][PF6], [Cu(xantphos)(2)][PF6], and [Cu(xantphos)(3)][PF6] have been characterized in solution using multinuclear NMR spectroscopy, and the single crystal structure of [Cu(xantphos)(3)][PF6].0.5Et2O was determined. The conformation of the 6-[2-(4-phenyl-1H-1,2,3,triazol-1-yl)ethyl]-substituent in the [Cu(xantphos)(3)]+ cation is such that the α- and β-CH2 units reside in the xanthene ‘bowl’ of the xantphos ligand. The 6-substituent desymmetrizes the structure of the [Cu(P^P)(N^N)]+ cation and this has consequences for the interpretation of the solution NMR spectra of the five complexes. The NOESY spectra and EXSY cross-peaks provide insight into the dynamic processes operating in the different compounds. For powdered samples, emission maxima are in the range 542–555 nm and photoluminescence quantum yields (PLQYs) lie in the range 13–28%, and a comparison of PLQYs and decay lifetimes with those of [Cu(xantphos)(6-Mebpy)][PF6] indicate that the introduction of the 6-substituent is not detrimental in terms of the photophysical properties.
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Rentschler M, Schmid MA, Frey W, Tschierlei S, Karnahl M. Multidentate Phenanthroline Ligands Containing Additional Donor Moieties and Their Resulting Cu(I) and Ru(II) Photosensitizers: A Comparative Study. Inorg Chem 2020; 59:14762-14771. [PMID: 32212646 DOI: 10.1021/acs.inorgchem.9b03687] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
To bind or not to bind: Driven by the motivation to increase the (photo)stability of traditional Cu(I) photosensitizers, multidentate diimine ligands, which contain two additional donor sites, were designed. To this end, a systematic series of four 1,10-phenanthroline ligands with either OR or SR (R = iPr or Ph) donor groups at the 2 and 9 positions and their resulting hetero- and homoleptic Cu(I) complexes were prepared. In addition, the related Ru(II) complexes were also synthesized to study the effect of another metal center. In the following, a combination of NMR spectroscopy and X-ray analysis was used to evaluate the impact of the additional donor moieties on the coordination behavior. Most remarkably, for the homoleptic bis(diimine)copper(I) complexes, a pentacoordinated copper center, corresponding to a (4 + 1)-fold coordination mode, was found in the solid state. This additional binding is the first indication that the extra donor might also occupy a free coordination site in the excited-state complex, modifying the nature of the excited states and their respective deactivation processes. Therefore, the electrochemical and photophysical properties of all novel complexes (in total 13) were studied in detail to assess the potential of these photosensitizers for future applications within solar energy conversion schemes. Finally, the photostabilities and a potential degradation mechanism were analyzed for representative samples.
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Affiliation(s)
- Martin Rentschler
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Marie-Ann Schmid
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Wolfgang Frey
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Stefanie Tschierlei
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Michael Karnahl
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
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19
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Rentschler M, Iglesias S, Schmid MA, Liu C, Tschierlei S, Frey W, Zhang X, Karnahl M, Moonshiram D. The Coordination Behaviour of Cu I Photosensitizers Bearing Multidentate Ligands Investigated by X-ray Absorption Spectroscopy. Chemistry 2020; 26:9527-9536. [PMID: 32162730 PMCID: PMC7496955 DOI: 10.1002/chem.201905601] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/20/2020] [Indexed: 12/05/2022]
Abstract
A systematic series of four novel homo‐ and heteroleptic CuI photosensitizers based on tetradentate 1,10‐phenanthroline ligands of the type X^N^N^X containing two additional donor moieties in the 2,9‐position (X=SMe or OMe) were designed. Their solid‐state structures were assessed by X‐ray diffraction. Cyclic voltammetry, UV‐vis absorption, emission and X‐ray absorption spectroscopy were then used to determine their electrochemical, photophysical and structural features in solution. Following, time‐resolved X‐ray absorption spectroscopy in the picosecond time scale, coupled with time‐dependent density functional theory calculations, provided in‐depth information on the excited state electron configurations. For the first time, a significant shortening of the Cu−X distance and a change in the coordination mode to a pentacoordinated geometry is shown in the excited states of the two homoleptic complexes. These findings are important with respect to a precise understanding of the excited state structures and a further stabilization of this type of photosensitizers.
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Affiliation(s)
- Martin Rentschler
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Sirma Iglesias
- Instituto Madrileño de Estudios Avanzados en, Nanociencia (IMDEA Nanociencia), Calle Faraday, 9, 28049, Madrid, Spain
| | - Marie-Ann Schmid
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Cunming Liu
- X-ray Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, IL, 60439, USA
| | - Stefanie Tschierlei
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Wolfgang Frey
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Xiaoyi Zhang
- X-ray Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, IL, 60439, USA
| | - Michael Karnahl
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Dooshaye Moonshiram
- Instituto Madrileño de Estudios Avanzados en, Nanociencia (IMDEA Nanociencia), Calle Faraday, 9, 28049, Madrid, Spain
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20
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Positional Isomerism in the N^N Ligand: How Much Difference Does a Methyl Group Make in [Cu(P^P)(N^N)] + Complexes? Molecules 2020; 25:molecules25122760. [PMID: 32549279 PMCID: PMC7356218 DOI: 10.3390/molecules25122760] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/11/2020] [Accepted: 06/12/2020] [Indexed: 12/16/2022] Open
Abstract
The synthesis and structural characterization of 5,6′-dimethyl-2,2′-bipyridine (5,6′-Me2bpy) are reported, along with the preparations and characterizations of [Cu(POP)(5,6′-Me2bpy)][PF6] and [Cu(xantphos)(5,6′-Me2bpy)][PF6] (POP = bis(2-(diphenylphosphanyl)phenyl)ether, xantphos = 4,5-bis(diphenylphosphanyl)-9,9-dimethyl-9H-xanthene). Single-crystal X-ray structure determinations of [Cu(POP)(5,6′-Me2bpy)][PF6] and [Cu(xantphos)(5,6′-Me2bpy)][PF6] confirmed distorted tetrahedral copper(I) coordination environments with the 5-methylpyridine ring of 5,6′-Me2bpy directed towards the (C6H4)2O unit of POP or the xanthene unit of xantphos. In the xantphos case, this preference may be attributed to C–H…π interactions involving both the 6-CH unit and the 5-methyl substituent in the 5-methylpyridine ring and the arene rings of the xanthene unit. 1H NMR spectroscopic data indicate that this ligand orientation is also preferred in solution. In solution and the solid state, [Cu(POP)(5,6′-Me2bpy)][PF6] and [Cu(xantphos)(5,6′-Me2bpy)][PF6] are yellow emitters, and, for powdered samples, photoluminescence quantum yields (PLQYs) are 12 and 11%, respectively, and excited-state lifetimes are 5 and 6 μs, respectively. These values are lower than PLQY and τ values for [Cu(POP)(6,6′-Me2bpy)][PF6] and [Cu(xantphos)(6,6′-Me2bpy)][PF6], and the investigation points to the 6,6′-dimethyl substitution pattern in the bpy ligand being critical for enhancement of the PLQY.
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21
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Alkan-Zambada M, Constable EC, Housecroft CE. The Role of Percent Volume Buried in the Characterization of Copper(I) Complexes for Lighting Purposes. Molecules 2020; 25:molecules25112647. [PMID: 32517264 PMCID: PMC7321245 DOI: 10.3390/molecules25112647] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/02/2020] [Accepted: 06/03/2020] [Indexed: 12/19/2022] Open
Abstract
The usefulness of percent volume buried (%Vbur) as a readily quantifiable property is investigated with regard to [Cu(NN)(PP)]+ complexes of interest for lighting purposes. Photoluminescence quantum yields (PLQYs) and single crystal X-ray structures of 100 reported compounds were assembled, %Vbur of the ligand systems were calculated and analyzed for correlations. We found that increased shielding of the central Cu(I) cation relying on shared contributions of both (NN) and (PP) ligand systems led to increased PLQYs. These findings are of relevance for future characterizations of Cu(I)-based complexes and their photophysical behavior in the solid-state.
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Affiliation(s)
- Murat Alkan-Zambada
- Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), ISIC-LSCI, BCH 3305, 1015 Lausanne, Switzerland
- Correspondence:
| | - Edwin C. Constable
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058 Basel, Switzerland; (E.C.C.); (C.E.H.)
| | - Catherine E. Housecroft
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058 Basel, Switzerland; (E.C.C.); (C.E.H.)
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Abstract
The syntheses and characterizations of the chelating ligand 6-chloro-6′-methyl-2,2′-bipyridine (6-Cl-6′-Mebpy) and of the copper(I) compounds [Cu(POP)(6-Cl-6′-Mebpy)][PF6] and [Cu(xantphos)(6-Cl-6′-Mebpy)][PF6] (POP = bis(2-(diphenylphosphanyl)phenyl)ether and xantphos = 4,5-bis(diphenylphosphanyl)-9,9-dimethyl-9H-xanthene) are described. The single crystal structures of both complexes were determined; the copper(I) ion is in a distorted tetrahedral environment and in [Cu(xantphos)(6-Cl-6′-Mebpy)][PF6], the disorder of the 6-Cl-6′-Mebpy ligand indicates there is no preference of the ‘bowl’-like cavity of the xanthene unit to host either the methyl or chloro-substituent, consistent with comparable steric effects of the two groups. The electrochemical and photophysical properties of [Cu(POP)(6-Cl-6′-Mebpy)][PF6] and [Cu(xantphos)(6-Cl-6′-Mebpy)][PF6] were investigated and are compared with those of the related compounds containing 6,6′-dichloro-2,2′-bipyridine or 6,6′-dimethyl-2,2′-bipyridine ligands. Trends in properties of the [Cu(P^P)(N^N)]+ complexes were consistent with 6-Cl-6′-Mebpy behaving as a combination of the two parent ligands.
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Extended π-Systems in Diimine Ligands in [Cu(P^P)(N^N)][PF6] Complexes: From 2,2′-Bipyridine to 2-(Pyridin-2-yl)Quinoline. CRYSTALS 2020. [DOI: 10.3390/cryst10040255] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We describe the synthesis and characterization of [Cu(POP)(1)][PF6], [Cu(POP)(2)][PF6], [Cu(xantphos)(1)][PF6], and [Cu(xantphos)(2)][PF6] in which ligands 1 and 2 are 2-(pyridin-2-yl)quinoline and 2-(6-methylpyridin-2-yl)quinoline, respectively. With 2,2'-bipyridine (bpy) as a benchmark, we assess the impact of the extended π-system on structural and solid-state photophysical properties. The single crystal structures of [Cu(POP)(2)][PF6], [Cu(xantphos)(1)][PF6], and [Cu(xantphos)(2)][PF6] were determined and confirmed a distorted tetrahedral copper(I) coordination environment in each [Cu(P^P)(N^N)]+ cation. The xanthene unit in [Cu(xantphos)(1)][PF6] and [Cu(xantphos)(2)][PF6] hosts the quinoline unit of 1, and the 6-methylpyridine group of 2. 1H NMR spectroscopic data indicate that these different ligand orientations are also observed in acetone solution. In their crystal structures, the [Cu(POP)(2)]+, [Cu(xantphos)(1)]+, and [Cu(xantphos)(2)]+ cations exhibit different edge-to-face and face-to-face π-interactions, but in all cases, the copper(I) centre is effectively protected by a ligand sheath. In [Cu(POP)(2)][PF6], pairs of cations engage in an efficient face-to-face π-stacking embrace, and we suggest that this may contribute to this compound having the highest photoluminescence quantum yield (PLQY = 21%) of the series. With reference to data from the Cambridge Structural Database, we compare packing effects and PLQY data for the complexes incorporating 2-(pyridin-2-yl)quinoline and 2-(6-methylpyridin-2-yl)quinoline, with those of the benchmark bpy-containing compounds. We also assess the effect that Cu⋯O distances in the {Cu(POP)} and {Cu(xantphos)} domains of [Cu(P^P)(N^N)][X] compounds have on solid-state PLQY values.
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24
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Giereth R, Mengele AK, Frey W, Kloß M, Steffen A, Karnahl M, Tschierlei S. Copper(I) Phosphinooxazoline Complexes: Impact of the Ligand Substitution and Steric Demand on the Electrochemical and Photophysical Properties. Chemistry 2020; 26:2675-2684. [PMID: 31747089 PMCID: PMC7065177 DOI: 10.1002/chem.201904379] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Indexed: 12/29/2022]
Abstract
A series of seven homoleptic CuI complexes based on hetero-bidentate P^N ligands was synthesized and comprehensively characterized. In order to study structure-property relationships, the type, size, number and configuration of substituents at the phosphinooxazoline (phox) ligands were systematically varied. To this end, a combination of X-ray diffraction, NMR spectroscopy, steady-state absorption and emission spectroscopy, time-resolved emission spectroscopy, quenching experiments and cyclic voltammetry was used to assess the photophysical and electrochemical properties. Furthermore, time-dependent density functional theory calculations were applied to also analyze the excited state structures and characteristics. Surprisingly, a strong dependency on the chirality of the respective P^N ligand was found, whereas the specific kind and size of the different substituents has only a minor impact on the properties in solution. Most importantly, all complexes except C3 are photostable in solution and show fully reversible redox processes. Sacrificial reductants were applied to demonstrate a successful electron transfer upon light irradiation. These properties render this class of photosensitizers as potential candidates for solar energy conversion issues.
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Affiliation(s)
- Robin Giereth
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Alexander K Mengele
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Wolfgang Frey
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Marvin Kloß
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 6, 44227, Dortmund, Germany
| | - Andreas Steffen
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 6, 44227, Dortmund, Germany
| | - Michael Karnahl
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Stefanie Tschierlei
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
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25
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Heteroleptic [Cu(P^P)(N^N)][PF6] Compounds with Isomeric Dibromo-1,10-Phenanthroline Ligands. INORGANICS 2020. [DOI: 10.3390/inorganics8010004] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A series of [Cu(P^P)(N^N)][PF6] compounds are reported in which N^N is 2,9-dibromo-1,10-phenanthroline (2,9-Br2phen), 3,8-dibromo-1,10-phenanthroline (3,8-Br2phen) or 4,7-dibromo-1,10-phenanthroline (4,7-Br2phen) and P^P is bis(2-(diphenylphosphano)phenyl)ether (POP) or 4,5-bis(diphenylphosphano)-9,9-dimethylxanthene (xantphos). The compounds were characterized by solution multinuclear NMR spectroscopy, mass spectrometry and a single-crystal X-ray analysis. Each compound underwent a partially reversible or irreversible copper-centred oxidation, the highest potential being for 2,9-Br2phen-containing compounds. In solution, the compounds are weak yellow or orange emitters, whereas powdered samples exhibit yellow emissions with photoluminescence quantum yields of up to 45% for [Cu(xantphos)(2,9-Br2phen)][PF6] with an excited state lifetime τ1/2 = 9.9 μs. Values of λemmax for [Cu(POP)(2,9-Br2phen)][PF6] and [Cu(xantphos)(2,9-Br2phen)][PF6] are blue-shifted with respect to compounds with the 3,8-and 4,7-isomers, both in solution and in the solid state.
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Pan X, Kuang XN, Zhu N, Wang G, Yang YP, Liu JM, Li ZF, Xin XL, Han HL, Jin QH, Ren ZG, Zhang JW. Terahertz time-domain absorption spectra of Cu(i) complexes bearing tetraphosphine ligands: the bridge between the C–H⋯π and π⋯π interactions and photoluminescence properties. Dalton Trans 2020; 49:14941-14950. [DOI: 10.1039/d0dt02542a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The terahertz spectrum bridges the luminescence and C–H⋯π and π⋯π interactions of Cu(i) complexes.
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Keller S, Prescimone A, La Placa MG, Junquera-Hernández JM, Bolink HJ, Constable EC, Sessolo M, Ortí E, Housecroft CE. The shiny side of copper: bringing copper(i) light-emitting electrochemical cells closer to application. RSC Adv 2020; 10:22631-22644. [PMID: 35514545 PMCID: PMC9054616 DOI: 10.1039/d0ra03824e] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 05/31/2020] [Indexed: 01/06/2023] Open
Abstract
Heteroleptic [Cu(P^P)(N^N)][PF6] complexes, where N^N is 5,5′-dimethyl-2,2′-bipyridine (5,5′-Me2bpy), 4,5,6-trimethyl-2,2′-bipyridine (4,5,6-Me3bpy), 6-(tert-butyl)-2,2′-bipyridine (6-tBubpy) and 2-ethyl-1,10-phenanthroline (2-Etphen) and P^P is either bis(2-(diphenylphosphino)phenyl)ether (POP, PIN [oxydi(2,1-phenylene)]bis(diphenylphosphane)) or 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos, PIN (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane)) have been synthesized and their NMR spectroscopic, mass spectrometric, structural, electrochemical and photophysical properties were investigated. The single-crystal structures of [Cu(POP)(5,5′-Me2bpy)][PF6], [Cu(xantphos)(5,5′-Me2bpy)][PF6], [Cu(POP)(6-tBubpy)][PF6], [Cu(POP)(4,5,6-Me3bpy)][PF6]·1.5Et2O, [Cu(xantphos)(4,5,6-Me3bpy)][PF6]·2.33CH2Cl2, [Cu(POP)(2-Etphen)][PF6] and [Cu(xantphos)(2-Etphen)][PF6] are described. While alkyl substituents in general exhibit electron-donating properties, variation in the nature and substitution-position of the alkyl group in the N^N chelate leads to different effects in the photophysical properties of the [Cu(P^P)(N^N)][PF6] complexes. In the solid state, the complexes are yellow to green emitters with emission maxima between 518 and 602 nm, and photoluminescence quantum yields (PLQYs) ranging from 1.1 to 58.8%. All complexes show thermally activated delayed fluorescence (TADF). The complexes were employed in the active layer of light-emitting electrochemical cells (LECs). The device performance properties are among the best reported for copper-based LECs, with maximum luminance values of up to 462 cd m−2 and device half-lifetimes of up to 98 hours. Heteroleptic copper(i) complexes with bisphosphanes and astutely tuned N^N chelating ligands as emitters give bright LECs with record-breaking stability.![]()
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Affiliation(s)
- Sarah Keller
- Department of Chemistry
- University of Basel
- CH-4058 Basel
- Switzerland
| | | | | | | | - Henk J. Bolink
- Instituto de Ciencia Molecular
- Universidad de Valencia
- 46980 Paterna
- Spain
| | | | - Michele Sessolo
- Instituto de Ciencia Molecular
- Universidad de Valencia
- 46980 Paterna
- Spain
| | - Enrique Ortí
- Instituto de Ciencia Molecular
- Universidad de Valencia
- 46980 Paterna
- Spain
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Omary MA, Determan JJ, Palehepitiya Gamage CS, Sinha P, Li S, Patterson MR, Nestero VN, Wilson AK, Rasika Dias HV. Is a High Photoluminescence Quantum Yield Good Enough for OLEDs? Can Luminescence Rigidochromism Be Manifest in the Solid State? an Optoelectronic Device Screening Case Study for Diphosphine/Pyrazolate Copper(I) Complexes. COMMENT INORG CHEM 2019. [DOI: 10.1080/02603594.2019.1701448] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Mohammad A. Omary
- Department of Chemistry, University of North Texas, Denton, Texas, USA
| | - John J. Determan
- Department of Chemistry, Western Illinois University, Macomb, Illinois, USA
| | | | - Pankaj Sinha
- Department of Chemistry, University of North Texas, Denton, Texas, USA
| | - Shan Li
- Department of Chemistry, University of North Texas, Denton, Texas, USA
| | - Monika R. Patterson
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, USA
| | | | - Angela K. Wilson
- Department of Chemistry, University of North Texas, Denton, Texas, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan, USA
| | - H. V. Rasika Dias
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, USA
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Abstract
A series of [Cu(POP)(N^N][PF6] and [Cu(xantphos)(N^N][PF6] compounds has been prepared and characterized in which POP = bis[2-(diphenylphosphanyl)phenyl]ether (IUPAC PIN oxydi(2,1-phenylene)bis(diphenylphosphane), xantphos = 4,5-bis(diphenylphosphanyl)-9,9-dimethyl-9H-xanthene (IUPAC PIN (9,9-dimethyl-9H-xanthene- 4,5-diyl)bis(diphenylphosphane)) and the N^N ligands are 4-(4-bromophenyl)-6,6′-dimethyl-2,2′- bipyridine (1), 5,5′-bis(3-methoxyphenyl)-6-methyl-2,2′-bipyridine (2), and 6-benzyl-2,2′-bipyridine (3). The single crystal structures of [Cu(xantphos)(1)][PF6]·CH2Cl2, [Cu(xantphos)(2)][PF6]·CH2Cl2 and [Cu(POP)(3)][PF6]·0.5H2O were determined by X-ray diffraction. Each complex contains a copper(I) ion in a distorted tetrahedral environment with chelating N^N and P^P ligands. In the [Cu(xantphos)(1)]+ and [Cu(xantphos)(2)]+ cations, there are face-to-face π-stackings of bpy and PPh2 phenyl rings (i.e., between the ligands); in addition in [Cu(xantphos)(2)][PF6]·CH2Cl2, inter-cation π-embraces lead to the formation of infinite chains as a primary packing motif. In [Cu(POP)(3)][PF6]·0.5H2O, centrosymmetric pairs of [Cu(POP)(3)]+ cations engage in C–H…π (phenyl to bpy) and offset face-to-face (bpy…bpy) contacts. The electrochemical and photophysical properties of the compounds containing ligands 1 and 2 are reported. They are green or yellow emitters in the solid-state (λem in the range 535–577 nm) with values for the photoluminescence quantum yield (PLQY) in the range 19%–41%.
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Zhang L, Zuo Q. A series of blue-green-yellow-red emitting Cu(I) complexes: Molecular structure and photophysical performance. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 223:117280. [PMID: 31234018 DOI: 10.1016/j.saa.2019.117280] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/14/2019] [Accepted: 06/15/2019] [Indexed: 06/09/2023]
Abstract
In this work, we designed a series of [Cu(NN)(PPh3)2]BF4 complexes with different optical edge values and emission colors from blue to red, where NN and PPh3 denoted a diamine ligand and triphenylphosphine, respectively. Six NN ligands with various conjugation chains (short π chain, modest π chain and long π chain) were selected. A systematical comparison between these Cu(I) complexes was performed, so that the correlation between NN structure and [Cu(NN)(PPh3)2] photophysical performance was tentatively discussed. Their single crystal structure was found consistent with literature ones, forming a typical tetrahedral coordination geometry. Density functional theory calculation indicated that their onset electronic transition showed a mixed character of metal-to-ligand-charge-transfer and ligand-to-ligand-charge-transfer. Detailed analysis on photophysical parameters suggested that the absorption edge of [Cu(NN)(PPh3)2]BF4 complex was controlled by conjugation length in diamine ligand. A wide absorption edge needed a short conjugation chain in diamine ligand. Similar tendency was found for their emission spectra. In addition, a long conjugation chain in diamine ligand widened emission spectra obviously. Emission dynamics showed slim correlation with diamine ligand conjugation length since the excited state was controlled mainly by dynamic procedure and steric factor of diamine ligands.
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Affiliation(s)
- Liming Zhang
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, PR China.
| | - Qinghui Zuo
- School of Materials Science and Engineering, Changchun University of Science and Technology, No. 7989, Weixing Road, Changchun 130022, PR China.
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Keller S, Bantle M, Prescimone A, Constable EC, Housecroft CE. Hinged and Wide: A New P^P Ligand for Emissive [Cu(P^P)(N^N)][PF 6] Complexes. Molecules 2019; 24:E3934. [PMID: 31683579 PMCID: PMC6864541 DOI: 10.3390/molecules24213934] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 10/29/2019] [Accepted: 10/29/2019] [Indexed: 12/02/2022] Open
Abstract
Heteroleptic [Cu(BIPHEP)(N^N)][PF6] complexes (BIPHEP = 1,1'-biphenyl-2,2'-diylbis(diphenylphosphane)), in which N^N is 2,2'-bipyridine (bpy), 6-methyl-2,2'-bipyridine (6-Mebpy), 6-ethyl-2,2'-bipyridine (6-Etbpy), or 5,5'-dimethyl-2,2'-bipyridine (5,5'-Me2bpy), have been synthesized and characterized using multinuclear NMR spectroscopies and electrospray ionization mass spectrometry. The single crystal structures of [Cu(BIPHEP)(bpy)][PF6]∙CH2Cl2, [Cu(BIPHEP)(5,5'-Me2bpy)][PF6]∙CH2Cl2, [Cu(BIPHEP)(6-Mebpy)][PF6]∙Et2O∙0.5H2O and [Cu(BIPHEP)(6-Etbpy)][PF6] confirm distorted tetrahedral {Cu(P^P)(N^N)} coordination environments. Each compound shows a quasi-reversible Cu+/Cu2+ process. In deaerated solution, the compounds are weak emitters. Powdered samples are yellow emitters (λemmax in the range 558-583 nm) and [Cu(BIPHEP)(5,5'-Me2bpy)][PF6] exhibits the highest photoluminescence quantum yield (PLQY = 14%). On cooling to 77 K (frozen 2-methyloxolane), the emission maxima are red-shifted and the excited state lifetimes increase from τ1/2 < 8 μs, to τ1/2 values of up to 53 μs, consistent with the compounds with N^N = 6-Mebpy, 6-Etbpy and 5,5'-Me2bpy exhibiting thermally activated delayed fluorescence (TADF).
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Affiliation(s)
- Sarah Keller
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058 Basel, Switzerland.
- Chimie ParisTech, PSL University CNRS, Institute of Chemistry for Life and Health Sciences, Laboratory for Inorganic Chemical Biology, 11 rue Pierre et Marie Curie, F-75005 Paris, France.
| | - Matthias Bantle
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058 Basel, Switzerland.
| | - Alessandro Prescimone
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058 Basel, Switzerland.
| | - Edwin C Constable
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058 Basel, Switzerland.
| | - Catherine E Housecroft
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058 Basel, Switzerland.
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New Push-Pull Fluorophores on the Basis of 6-Alkoxy-2,2'-Bipyridines: Rational Synthetic Approach and Photophysical Properties. Chem Heterocycl Compd (N Y) 2019. [DOI: 10.1007/s10593-019-02495-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Wang Z, Sun X, Xu C, Ji B. Synthesis, Structures, and Photophysical Properties of Novel Four-Coordinate Cu(I) Complexes Supported by Chelating N-Heterocyclic Carbene Ligands. Front Chem 2019; 7:422. [PMID: 31231640 PMCID: PMC6561309 DOI: 10.3389/fchem.2019.00422] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/21/2019] [Indexed: 01/09/2023] Open
Abstract
Luminescent Cu(I) complexes are promising emitting materials for electroluminescent devices due to their low cost and abundant resources, as well as high emission efficiency. It is well-known that N-heterocyclic carbenes (NHCs) are excellent ligands for transition metal complexes. To investigate the photophysical properties of Cu(I)-NHC complexes, a series of new mononuclear four-coordinate Cu(I) complexes supported by the diphosphine ligand bis[2-(diphenylphosphino)phenyl]ether (POP) and the NHC ligands, consisting of imidazolylidene and pyrimidine units, were synthesized and fully characterized. To tune the photophysical properties of these Cu(I)-NHC complexes, the NHC ligands were attached with electron-withdrawing/donating groups (fluorine, chlorine, methyl and methoxyl) at the pyrimidine unit. All of these Cu(I)-NHC complexes adopt the typical distorted tetrahedral configuration. The electron-donating groups can lead to shorter Cu–N bond distances and longer Cu–C bond distances compared to the electron-withdrawing groups. Theoretical calculation results show that the highest occupied molecular orbitals are mainly distributed on the Cu(I) ion, POP, and carbene unit, while the lowest unoccupied molecular orbitals are mostly located on the pyrimidine unit of NHC ligands. The lowest energy electronic transitions of these Cu(I)-NHC complexes are mainly the metal-to-ligand charge transfer transition and ligand-to-ligand charge transfer transition. These Cu(I)-NHC complexes in solid state show tunable emissions from 530 to 618 nm with efficiencies of 0.5–38.1% at room temperature. The photophysical behaviors of these complexes at 298 and 50 K match well with the thermally activated delayed fluorescence (TADF) characteristics.
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Affiliation(s)
- Zhiqiang Wang
- College of Chemistry and Chemical Engineering and Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University, Luoyang, China
| | - Xiaojuan Sun
- College of Chemistry and Chemical Engineering and Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University, Luoyang, China
| | - Chen Xu
- College of Food and Pharmacy, Luoyang Normal University, Luoyang, China
| | - Baoming Ji
- College of Chemistry and Chemical Engineering and Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University, Luoyang, China
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Liu X, Shan Y, Xu J, Zhang X, Shang S, Li XL. Alcohol soluble Cu(I) complexes with aggregation-induced phosphorescent emission in ethanol/water solvents. Polyhedron 2019. [DOI: 10.1016/j.poly.2019.02.054] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Föller J, Ganter C, Steffen A, Marian CM. Computer-Aided Design of Luminescent Linear N-Heterocyclic Carbene Copper(I) Pyridine Complexes. Inorg Chem 2019; 58:5446-5456. [PMID: 30995025 DOI: 10.1021/acs.inorgchem.9b00334] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Multireference configuration interaction methods including spin-orbit interactions have been employed to investigate the photophysical properties of various linear N-heterocyclic carbene (NHC) copper(I) pyridine complexes with the aim of designing performant thermally activated delayed fluorescence (TADF) emitters for use in organic-light-emitting diodes. Our theoretical results indicate that this structural motif is very favorable for generating excited triplet states with high quantum yield. The first excited singlet (SMLCT) and corresponding triplet state (TMLCT) are characterized by dσ → πPy metal-to-ligand charge-transfer (MLCT) excitations. Efficient intersystem crossing (ISC) and reverse ISC (rISC) between these states is mediated by a near-degenerate second triplet state (TMLCT/LC) with large dπ → πPy contributions. Spin-vibronic coupling is strong and is expected to play a major role in the (r)ISC processes. The calculations reveal, however, that the luminescence is effectively quenched by locally excited triplet states if the NHC ligand carries two diisopropylphenyl (DIPP) substituents. When DIPP is replaced with 1-adamantyl residues, this quenching process is suppressed and TADF in the UV spectral regime is predicted to proceed at a rate of about 1/μs. The introduction of +I substituents on the carbene and -M substituents on the pyridine allows tuning of the emission wavelength from the UV to the blue-green or green spectral region.
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Affiliation(s)
| | | | - Andreas Steffen
- Faculty of Chemistry and Chemical Biology , TU Dortmund University , Otto-Hahn-Strasse 6 , D-44227 Dortmund , Germany
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Abstract
We report the synthesis and characterization of [Cu(P^P)(N^S)][PF6] complexes with P^P = bis(2-(diphenylphosphino)phenyl) ether (POP) or 4,5-bis(diphenylphosphino)-9,9- dimethylxanthene (xantphos) and N^S = 2-(iso-propylthio)pyridine (iPrSpy) or 2-(tert-butylthio)pyridine (tBuSpy). The single crystal structures of [Cu(POP)(iPrSPy)][PF6] and [Cu(POP)(tBuSPy)][PF6] have been determined and confirm a distorted tetrahedral copper(I) centre and chelating P^P and N^S ligands in each complex. Variable temperature (VT) 1H and 31P{1H} NMR spectroscopy reveals dynamic behavior with motion of the POP backbone in [Cu(POP)(iPrSPy)][PF6] and [Cu(POP)(tBuSPy)][PF6] frozen out at 238 K. VT NMR spectroscopic data including EXSY peaks in the ROESY spectrum of [Cu(xantphos)(tBuSPy)][PF6] at 198 K reveal that two conformers exist in an approximate ratio of 5:1. Replacing bpy by the N^S ligands shifts the Cu+/Cu2+ oxidation to a higher potential. The copper(I) compounds are weak emitters in the solid state with PLQY values of <2%. These values are similar to those for [Cu(POP)(bpy)][PF6] and [Cu(xantphos)(bpy)][PF6] in the solid state.
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Artem'ev AV, Ryzhikov MR, Berezin AS, Kolesnikov IE, Samsonenko DG, Bagryanskaya IY. Photoluminescence of Ag(i) complexes with a square-planar coordination geometry: the first observation. Inorg Chem Front 2019. [DOI: 10.1039/c9qi00657e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
First examples of square-planar Ag(i) complexes showing MLCT emission are reported. They demonstrate an interesting thermochromic luminescence with the nano- and microsecond lifetime components.
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Affiliation(s)
- Alexander V. Artem'ev
- Nikolaev Institute of Inorganic Chemistry
- Siberian Branch of Russian Academy of Sciences
- Novosibirsk 630090
- Russian Federation
- Novosibirsk State University
| | - Maxim R. Ryzhikov
- Nikolaev Institute of Inorganic Chemistry
- Siberian Branch of Russian Academy of Sciences
- Novosibirsk 630090
- Russian Federation
- Novosibirsk State University
| | - Alexey S. Berezin
- Nikolaev Institute of Inorganic Chemistry
- Siberian Branch of Russian Academy of Sciences
- Novosibirsk 630090
- Russian Federation
| | - Ilya E. Kolesnikov
- Center for Optical and Laser Materials Research
- Saint Petersburg State University
- Saint Petersburg 198504
- Russian Federation
| | - Denis G. Samsonenko
- Nikolaev Institute of Inorganic Chemistry
- Siberian Branch of Russian Academy of Sciences
- Novosibirsk 630090
- Russian Federation
- Novosibirsk State University
| | - Irina Yu. Bagryanskaya
- Novosibirsk State University
- Novosibirsk 630090
- Russian Federation
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry
- Siberian Branch of Russian Academy of Sciences
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Nohara I, Prescimone A, Häussinger D, Housecroft CE, Constable EC. [Cu(POP)(N^S)][PF6] and [Cu(xantphos)(N^S)][PF6] compounds with 2-(thiophen-2-yl)pyridines. RSC Adv 2019; 9:13646-13657. [PMID: 35519553 PMCID: PMC9063866 DOI: 10.1039/c9ra02617g] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 04/24/2019] [Indexed: 11/29/2022] Open
Abstract
A series of [Cu(POP)(N^S)][PF6] and [Cu(xantphos)(N^S)][PF6] compounds (POP = bis(2-(diphenylphosphino)phenyl)ether, xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene) in which the N^S ligand is a 2-(thiophen-2-yl)pyridine (1), 2-(thiophen-2-yl)-6-methylpyridine (2), 2-(5-methylthiophen-2-yl)pyridine (3) or 2-(5-methylthiophen-2-yl)-6-methylpyridine (4) have been prepared and characterized in solution and the solid state. Single crystal structures of [Cu(POP)(1)][PF6], [Cu(xantphos)(1)][PF6], [Cu(xantphos)(2)][PF6], [Cu(POP)(3)][PF6]·CH2Cl2, and [Cu(xantphos)(4)][PF6] confirm chelating N^S and P^P ligands, and distorted tetrahedral copper(i) centres. There is close cation⋯anion association, particularly in [Cu(xantphos)(1)][PF6]. Although the compounds are stable over days in CH2Cl2 solution, they are susceptible to the effects of competing ligands such as chloride ion and MeCN. Analysis of the NMR spectroscopic data of a solution of [Cu(POP)(3)][PF6] with added Cl−, gives a Kd value of 0.14 ± 0.03 mM, indicative of ion-pairing. [Cu(POP)(N^S)][PF6] and [Cu(xantphos)(N^S)][PF6] exhibit quasi-reversible or irreversible Cu+/Cu2+ oxidations. They are blue emitters in solution, and the presence of the 5-methyl group in the thiophene ring in 3 and 4 leads to a red-shift in the emission. The highest photoluminescence quantum yields are for [Cu(POP)(2)][PF6] (30.8%) and [Cu(POP)(4)][PF6] (33.2%), both of which have a 6-methyl-substituted pyridine ring in the N^S ligand. Excited-state lifetimes are <5 ns. On going from solution to powder samples, red-shifts of 133 to 163 nm are observed leading to yellow emitters. The brightest emitter, [Cu(xantphos)(1)][PF6], was tested in a LEC device but showed poor electroluminescence and poor charge transporting characteristics. [Cu(P^P)(N^S)][PF6] with N^S = 2-(thiophen-2-yl)pyridines show close cation⋯anion association in the solid-state; complex cation association with Cl− occurs in solution. The compounds are blue-emitters in solution with a red-shift of the emission on going to the solid.![]()
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Affiliation(s)
- Isaak Nohara
- Department of Chemistry
- University of Basel
- CH4058 Basel
- Switzerland
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Artem'ev AV, Doronina EP, Rakhmanova MI, Tarasova OA, Bagryanskaya IY, Nedolya NA. Chemoselective mechanochemical route toward a bright TADF-emitting CuI-based coordination polymer. Inorg Chem Front 2019. [DOI: 10.1039/c8qi01302k] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a simple and effective mechanochemical synthesis of a strongly-emissive TADF-material based on a CuI-coordination polymer that is unobtainable through traditional wet methods.
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Affiliation(s)
- Alexander V. Artem'ev
- Nikolaev Institute of Inorganic Chemistry
- Siberian Branch of Russian Academy of Sciences
- Novosibirsk 630090
- Russian Federation
- Novosibirsk State University
| | - Evgeniya P. Doronina
- A. E. Favorsky Irkutsk Institute of Chemistry
- Siberian Branch of the Russian Academy of Sciences
- 664033 Irkutsk
- Russian Federation
| | - Mariana I. Rakhmanova
- Nikolaev Institute of Inorganic Chemistry
- Siberian Branch of Russian Academy of Sciences
- Novosibirsk 630090
- Russian Federation
- Novosibirsk State University
| | - Olga A. Tarasova
- A. E. Favorsky Irkutsk Institute of Chemistry
- Siberian Branch of the Russian Academy of Sciences
- 664033 Irkutsk
- Russian Federation
| | - Irina Yu. Bagryanskaya
- Novosibirsk State University
- Novosibirsk 630090
- Russian Federation
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry
- Siberian Branch of Russian Academy of Sciences
| | - Nina A. Nedolya
- A. E. Favorsky Irkutsk Institute of Chemistry
- Siberian Branch of the Russian Academy of Sciences
- 664033 Irkutsk
- Russian Federation
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Alkan-Zambada M, Hu X. Cu Photoredox Catalysts Supported by a 4,6-Disubstituted 2,2′-Bipyridine Ligand: Application in Chlorotrifluoromethylation of Alkenes. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00585] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Murat Alkan-Zambada
- Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), ISIC-LSCI, BCH
3305, Lausanne 1015, Switzerland
| | - Xile Hu
- Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), ISIC-LSCI, BCH
3305, Lausanne 1015, Switzerland
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