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Ogawa T, Wenger OS. Nickel(II) Analogues of Phosphorescent Platinum(II) Complexes with Picosecond Excited-State Decay. Angew Chem Int Ed Engl 2023; 62:e202312851. [PMID: 37732725 DOI: 10.1002/anie.202312851] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/22/2023]
Abstract
Square-planar NiII complexes are interesting as cheaper and more sustainable alternatives to PtII luminophores widely used in lighting and photocatalysis. We investigated the excited-state behavior of two NiII complexes, which are isostructural with two luminescent PtII complexes. The initially excited singlet metal-to-ligand charge transfer (1 MLCT) excited states in the NiII complexes decay to metal-centered (3 MC) excited states within less than 1 picosecond, followed by non-radiative relaxation of the 3 MC states to the electronic ground state within 9-21 ps. This contrasts with the population of an emissive triplet ligand-centered (3 LC) excited state upon excitation of the PtII analogues. Structural distortions of the NiII complexes are responsible for this discrepant behavior and lead to dark 3 MC states far lower in energy than the luminescent 3 LC states of PtII compounds. Our findings suggest that if these structural distortions could be restricted by more rigid coordination environments and stronger ligand fields, the excited-state relaxation in four-coordinate NiII complexes could be decelerated such that luminescent 3 LC or 3 MLCT excited states become accessible. These insights are relevant to make NiII fit for photophysical and photochemical applications that relied on PtII until now.
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Affiliation(s)
- Tomohiro Ogawa
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
- Graduate School of Science and Engineering, University of Toyama, Toyama, 930-8555, Japan
| | - Oliver S Wenger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
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2
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Johnson CE, Schwarz J, Deegbey M, Prakash O, Sharma K, Huang P, Ericsson T, Häggström L, Bendix J, Gupta AK, Jakubikova E, Wärnmark K, Lomoth R. Ferrous and ferric complexes with cyclometalating N-heterocyclic carbene ligands: a case of dual emission revisited. Chem Sci 2023; 14:10129-10139. [PMID: 37772113 PMCID: PMC10530338 DOI: 10.1039/d3sc02806b] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 08/27/2023] [Indexed: 09/30/2023] Open
Abstract
Iron N-heterocyclic carbene (FeNHC) complexes with long-lived charge transfer states are emerging as a promising class of photoactive materials. We have synthesized [FeII(ImP)2] (ImP = bis(2,6-bis(3-methylimidazol-2-ylidene-1-yl)phenylene)) that combines carbene ligands with cyclometalation for additionally improved ligand field strength. The 9 ps lifetime of its 3MLCT (metal-to-ligand charge transfer) state however reveals no benefit from cyclometalation compared to Fe(ii) complexes with NHC/pyridine or pure NHC ligand sets. In acetonitrile solution, the Fe(ii) complex forms a photoproduct that features emission characteristics (450 nm, 5.1 ns) that were previously attributed to a higher (2MLCT) state of its Fe(iii) analogue [FeIII(ImP)2]+, which led to a claim of dual (MLCT and LMCT) emission. Revisiting the photophysics of [FeIII(ImP)2]+, we confirmed however that higher (2MLCT) states of [FeIII(ImP)2]+ are short-lived (<10 ps) and therefore, in contrast to the previous interpretation, cannot give rise to emission on the nanosecond timescale. Accordingly, pristine [FeIII(ImP)2]+ prepared by us only shows red emission from its lower 2LMCT state (740 nm, 240 ps). The long-lived, higher energy emission previously reported for [FeIII(ImP)2]+ is instead attributed to an impurity, most probably a photoproduct of the Fe(ii) precursor. The previously reported emission quenching on the nanosecond time scale hence does not support any excited state reactivity of [FeIII(ImP)2]+ itself.
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Affiliation(s)
- Catherine Ellen Johnson
- Department of Chemistry -Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Jesper Schwarz
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University Box 124 SE-22100 Lund Sweden
| | - Mawuli Deegbey
- Department of Chemistry, North Carolina State University Raleigh North Carolina 27695 USA
| | - Om Prakash
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University Box 124 SE-22100 Lund Sweden
| | - Kumkum Sharma
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University Box 124 SE-22100 Lund Sweden
| | - Ping Huang
- Department of Chemistry -Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
| | - Tore Ericsson
- Department of Physics - Ångström Laboratory, Uppsala University Box 523 SE-751 20 Uppsala Sweden
| | - Lennart Häggström
- Department of Physics - Ångström Laboratory, Uppsala University Box 523 SE-751 20 Uppsala Sweden
| | - Jesper Bendix
- Department of Chemistry, University of Copenhagen Universitetsparken 5 DK-2100 Copenhagen Denmark
| | - Arvind Kumar Gupta
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University Box 124 SE-22100 Lund Sweden
| | - Elena Jakubikova
- Department of Chemistry, North Carolina State University Raleigh North Carolina 27695 USA
| | - Kenneth Wärnmark
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University Box 124 SE-22100 Lund Sweden
| | - Reiner Lomoth
- Department of Chemistry -Ångström Laboratory, Uppsala University Box 523 SE-75120 Uppsala Sweden
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3
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Amouri H. Luminescent Complexes of Platinum, Iridium, and Coinage Metals Containing N-Heterocyclic Carbene Ligands: Design, Structural Diversity, and Photophysical Properties. Chem Rev 2023; 123:230-270. [PMID: 36315851 DOI: 10.1021/acs.chemrev.2c00206] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The employment of N-heterocyclic carbenes (NHCs) to design luminescent metal compounds has been the focus of recent intense investigations because of the strong σ-donor properties, which bring stability to the whole system and tend to push the d-d dark states so high in energy that they are rendered thermally inaccessible, thereby generating highly emissive complexes for useful applications such as organic light-emitting diodes (OLEDs), or featuring chiroptical properties, a field that is still in its infancy. Among the NHC complexes, those containing organic chromophores such as naphthalimide, pyrene, and carbazole exhibit rich emission behavior and thus have attracted extensive interest in the past five years, especially carbene coinage metal complexes with carbazolate ligands. In this review, the design strategies of NHC-based luminescent platinum and iridium complexes with large spin-orbit-coupling (SOC) are described first. Subsequent paragraphs illustrate the recent advances of luminescent coinage metal complexes with nucleophilic- and electrophilic-based carbenes based on silver, gold, and copper metal complexes that have the ability to display rich excited state emissions in particular via thermally activated delayed fluorescence (TADF). The luminescence mechanism and excited state dynamics are also described. We then summarize the advance of NHC-metal complexes in the aforementioned fields in recent years. Finally, we propose the development trend of this fast-growing field of luminescent NHC-metal complexes.
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Affiliation(s)
- Hani Amouri
- CNRS, IPCM (UMR 8232), Sorbonne Université-Faculté des Sciences et Ingénerie Campus Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris, Cedex 05, France
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Gómez de Segura D, Lalinde E, Moreno MT. Polymorphism and Mechanochromism in 2-Phenylbenzothiazole Cyclometalated Pt II Complexes with Chelating N ∧O Ligands. Inorg Chem 2022; 61:20043-20056. [PMID: 36442499 DOI: 10.1021/acs.inorgchem.2c03423] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
New cyclometalated PtII complexes with 2-phenylbenzothiazole (pbt) and two different picolinate ligands [Pt(pbt)(R-pic-κN,O)] (R = H (1), OH (2)) were prepared. In contrast to 1, the OH substituent group on 2 allows modulation of the packing in the solid state through donor-acceptor H-bonding interactions with the CH2Cl2 solvent. Thus, three pseudopolymorphs of 2 with different aggregation degrees were isolated, including yellow 2-Y, orange-red 2-R (2·0.5CH2Cl2) and black 2-B (2·0.75CH2Cl2) with emissions at 540, 656, and 740 nm, respectively, in the solid state at 298 K. 2-R and 2-B can be transformed to the pristine solid 2. Studies of their crystal structures show that 1 and 2-Y stack in columns with only π···π stacking interactions, whereas 2-R displays strong aggregated 1D infinite chains based on Pt···Pt and π···π stacking interactions, consistent with the colors and the photophysical properties, measured in several media. Interestingly, 1 and 2 exhibit reversible mechanochromic behavior with high contrast in the color and color emission upon mechanical grinding due to a phase transition between a crystalline and an amorphous state, as confirmed by powder X-ray diffraction (PXRD) studies. Theoretical calculations indicate that Pt···Pt contacts are more relevant in the trimers and tetramers than in the dimers, particularly in their T1 states, associated with a change from a 3IL/3MLCT transition in the monomer to 3MM(L+L')CT in the oligomers. Noncovalent interaction (NCI) theoretical studies indicate that the π···π stacking among chelates also exerts a strong influence in the metal-metal-to-ligand charge transfer transition character.
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Affiliation(s)
- David Gómez de Segura
- Departamento de Química-Centro de Síntesis Química de La Rioja (CISQ), Universidad de La Rioja, 26006 Logroño, Spain
| | - Elena Lalinde
- Departamento de Química-Centro de Síntesis Química de La Rioja (CISQ), Universidad de La Rioja, 26006 Logroño, Spain
| | - M Teresa Moreno
- Departamento de Química-Centro de Síntesis Química de La Rioja (CISQ), Universidad de La Rioja, 26006 Logroño, Spain
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5
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Ogawa T, Sinha N, Pfund B, Prescimone A, Wenger OS. Molecular Design Principles to Elongate the Metal-to-Ligand Charge Transfer Excited-State Lifetimes of Square-Planar Nickel(II) Complexes. J Am Chem Soc 2022; 144:21948-21960. [DOI: 10.1021/jacs.2c08838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Tomohiro Ogawa
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Narayan Sinha
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Björn Pfund
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Alessandro Prescimone
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Oliver S. Wenger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
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6
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Group 10 metal-cyanide scaffolds in complexes and extended frameworks: Properties and applications. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2021.214310] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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7
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Liska T, Swetz A, Lai PN, Zeller M, Teets TS, Gray TG. Room-Temperature Phosphorescent Platinum(II) Alkynyls with Microsecond Lifetimes Bearing a Strong-Field Pincer Ligand. Chemistry 2020; 26:8417-8425. [PMID: 32150648 DOI: 10.1002/chem.202000500] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Indexed: 01/28/2023]
Abstract
The use of organometallic triplet emitters in organic light emitting diodes (OLEDs) is motivated by the premise of efficient intersystem crossing leading to unit internal quantum efficiencies. However, since most devices are based on solid-state components, an inherent limitation to square-planar platinum(II) phosphors is their tendency toward aggregation-based quenching. Here, a new class of emissive, four-coordinate PtII species based on the bisimidazolyl carbazolide (BIMCA) ligand is introduced, which displays highly efficient, long-lived solid-state phosphorescence at room temperature. A set of four BIMCAPt phenyl acetylides were synthesized that emit in the green (λmax =507-540 nm) with >60 % quantum yield and millisecond lifetimes. The structures of the resulting species reveal a non-planar structure imposed by steric clashes between BIMCA and the iodo or alkynyl co-ligand. Ground-state and photophysical characterization are presented. Density functional theory calculations indicate that the BIMCA ligand dominates the frontier orbitals along with the first Franck-Condon singlet and triplet excited states.
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Affiliation(s)
- Tadeas Liska
- Department of Chemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA
| | - Anna Swetz
- Department of Chemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA
| | - Po-Ni Lai
- Department of Chemistry, University of Houston, 3585 Cullen Boulevard, Room 112, Houston, Texas, 77204, USA
| | - Matthias Zeller
- Department of Chemistry, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Thomas S Teets
- Department of Chemistry, University of Houston, 3585 Cullen Boulevard, Room 112, Houston, Texas, 77204, USA
| | - Thomas G Gray
- Department of Chemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA
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Io K, Ng S, Yeung C, Wong C. Synthesis, Spectroscopic and Computational Studies of Rhodium(III) Complexes Bearing N‐Heterocyclic Carbene‐Based C
^
N
^
C Pincer Ligand and Bipyridine/Terpyridine. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Kai‐Wa Io
- Department of Chemistry City University of Hong Kong Tat Chee Avenue Kowloon Hong Kong SAR
| | - Sze‐Wing Ng
- Department of Chemistry City University of Hong Kong Tat Chee Avenue Kowloon Hong Kong SAR
| | - Chi‐Fung Yeung
- Department of Chemistry City University of Hong Kong Tat Chee Avenue Kowloon Hong Kong SAR
| | - Chun‐Yuen Wong
- Department of Chemistry City University of Hong Kong Tat Chee Avenue Kowloon Hong Kong SAR
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9
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Wang Z, Jiang L, Ng CK, Song X, Hor TSA, Zhao J. Isolation and Crystallographic Identification of Photoactive Pt
II
Tris‐ and Bis(
N
‐methylbenzimidazole‐NHC) Complexes. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201800868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Zhe Wang
- Institute of Materials Research and Engineering Agency for Science Innovis 2 Fusionopolis Way 138634 Singapore Singapore
- Department of Chemistry National University of Singapore 3 Science Drive 3 117543 Singapore Singapore
| | - Lu Jiang
- Institute of Materials Research and Engineering Agency for Science Innovis 2 Fusionopolis Way 138634 Singapore Singapore
| | - Chee Koon Ng
- Institute of Materials Research and Engineering Agency for Science Innovis 2 Fusionopolis Way 138634 Singapore Singapore
| | - Xiaolu Song
- Institute of Materials Research and Engineering Agency for Science Innovis 2 Fusionopolis Way 138634 Singapore Singapore
| | - T. S. Andy Hor
- Department of Chemistry The University of Hong Kong Pokfulam Hong Kong SAR China
| | - Jin Zhao
- Institute of Materials Research and Engineering Agency for Science Innovis 2 Fusionopolis Way 138634 Singapore Singapore
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10
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Cope JD, Denny JA, Lamb RW, McNamara LE, Hammer NI, Webster CE, Hollis TK. Synthesis, characterization, photophysics, and a ligand rearrangement of CCC-NHC pincer nickel complexes: Colors, polymorphs, emission, and Raman spectra. J Organomet Chem 2017. [DOI: 10.1016/j.jorganchem.2017.05.046] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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11
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Takayasu S, Shinozaki K. Hydration of fac-tris(2-phenylpyridinato-C2,N)iridium(III) in dichloromethane solution and in solid state. Polyhedron 2017. [DOI: 10.1016/j.poly.2016.12.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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12
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The influence of ancillary ligands on the antitumoral activity of new cyclometallated Pt(II) complexes derived from an ferrocene-pyrazole hybrid. J Organomet Chem 2017. [DOI: 10.1016/j.jorganchem.2016.11.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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13
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Application of five-membered ring products of cyclometalation reactions as sensing materials in sensing devices. J Organomet Chem 2016. [DOI: 10.1016/j.jorganchem.2016.09.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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14
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Naziruddin AR, Lee CS, Lin WJ, Sun BJ, Chao KH, Chang AHH, Hwang WS. Platinum complexes bearing normal and mesoionic N-heterocyclic carbene based pincer ligands: syntheses, structures, and photo-functional attributes. Dalton Trans 2016; 45:5848-59. [DOI: 10.1039/c5dt04770f] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Platinum complexes featuring pyridine bis-N-heterocyclic imidazol-2-ylidene/triazol-5-ylidene donors are prepared and screened for vapo/mechanochromic attributes.
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Affiliation(s)
| | | | - Wan-Jung Lin
- National Dong Hwa University
- Hualien 97401
- Republic of China
| | - Bing-Jian Sun
- National Dong Hwa University
- Hualien 97401
- Republic of China
| | - Kang-Heng Chao
- National Dong Hwa University
- Hualien 97401
- Republic of China
| | | | - Wen-Shu Hwang
- National Dong Hwa University
- Hualien 97401
- Republic of China
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