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Liu S, Wang M, Hou T, Shen X. Unprecedented hetero-coordinated Ir(C^N) 2tmd complexes containing both five- and six-membered Ir-(C^N) rings based on phenanthrylpyridine ligands: syntheses, crystal structures and photophysical properties. Dalton Trans 2023; 52:11120-11129. [PMID: 37494113 DOI: 10.1039/d3dt01809a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
By using 2-(9-phenanthryl)pyridine (phpyr) and its derivatives as cyclometalated ligands, we synthesized a set of isomeric red-emitting complexes Ir(phpyr-R)2tmd (R = -H, -CF3, -F and -CH3, tmd = 2,2,6,6-tetramethylheptane-3,5-dione) with different coordinated modes, including bis-five-membered and five- + six-membered Ir-(C^N) ring chelating modes. The latter are the first examples of hetero-coordinated Ir(C^N)2(L^X)-type complexes containing both five- and six-membered Ir-(C^N) metallocycles. Their coordination geometries were distinctly determined using X-ray crystallographic analysis. Compared to typical bis-five-membered ring-chelated complexes, these novel hetero-coordinated isomers show bathochromic emission and lower quantum yields. On careful analysis of their electrochemical behavior and DFT calculations, it has been found that the regulatory effects of the solitary six-membered metallocycles in Ir(phpyr-R)2tmd could not only stabilize the LUMO but also destabilize the HOMO, leading to a narrower energy gap. More importantly, DFT calculations of the relative energies of these isomeric complexes demonstrated that bis-five-membered and five- + six-membered chelating modes are more stable compared to bis-six-membered rings, consistent with experiments. This work provides guidance for the structural design of Ir(C^N)2(L^X)-type complexes.
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Affiliation(s)
- Sen Liu
- State Key Laboratory of Materials-oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
- Zhangjiagang Institute of Nanjing Tech University, Suzhou 215600, P. R. China
| | - Mengyun Wang
- State Key Laboratory of Materials-oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
| | - Tianjiao Hou
- State Key Laboratory of Materials-oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
- Jiangsu Academy of Chemical Inherent Safety, Nanjing210009, P. R. China
| | - Xuan Shen
- State Key Laboratory of Materials-oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
- Zhangjiagang Institute of Nanjing Tech University, Suzhou 215600, P. R. China
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Tatarin SV, Smirnov DE, Taydakov IV, Metlin MT, Emets VV, Bezzubov SI. Tailoring the π-system of benzimidazole ligands towards stable light-harvesting cyclometalated iridium(III) complexes. Dalton Trans 2023; 52:6435-6450. [PMID: 37092600 DOI: 10.1039/d3dt00200d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
The synthesis, structure, optical and redox properties as well as photovoltaic studies of iridium(III) complexes with cyclometalated 2-arylbenzimidazoles decorated with various polyaromatic fragments and an ancillary aromatic β-diketone are reported. Despite the strong preference of the iridium(III) ion to form bis- or tris-cyclometalated complexes in which the metal participates in five-membered metallacycles, the cyclometalation of the benzimidazole ligands containing rigid π-extended systems yields dimeric complexes containing strained five- or six-membered metallacycles and allows for generating an extremely rare monocyclometalated complex. X-ray crystallography shows that the steric strain observed in the dimers is retained in heteroleptic diketonate complexes which is also corroborated by gas-phase DFT calculations. While emission maxima and redox potentials of the heteroleptic complexes exhibit just a moderate variation upon the change of the cyclometalated ligands, the extension of the π-system of the benzimidazole ligands give the complexes remarkable light absorption in the visible spectral range, which meets the requirements for application in dye-sensitized solar cells. At the titania photoanodes, these iridium dyes retain their optical properties and exhibit power conversion efficiencies under standard AM 1.5 G conditions comparable to those of other iridium-based sensitizers. These results demonstrate that the size and position of the π-extended fragment in cyclometalated ligands can modulate not only the electronic structure of the corresponding iridium(III) complexes, but also affect their composition, structure and reactivity that may find implications in future design of emerging iridium dyes, emitters and catalysts.
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Affiliation(s)
- Sergei V Tatarin
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow 119991, Russia.
| | - Daniil E Smirnov
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow 119991, Russia.
| | - Ilya V Taydakov
- P.N. Lebedev Physical Institute, Russian Academy of Sciences, 53 Leninsky Prospect, Moscow 119991, Russia
| | - Mikhail T Metlin
- P.N. Lebedev Physical Institute, Russian Academy of Sciences, 53 Leninsky Prospect, Moscow 119991, Russia
- Bauman Moscow State Technical University, 2-ya Baumanskaya Str. 5/1, 105005, Moscow, Russia
| | - Victor V Emets
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow 119071, Russia
| | - Stanislav I Bezzubov
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow 119991, Russia.
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Phosphorescent Ir(III) Complexes for Biolabeling and Biosensing. Top Curr Chem (Cham) 2022; 380:35. [PMID: 35948820 DOI: 10.1007/s41061-022-00389-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 05/27/2022] [Indexed: 10/15/2022]
Abstract
Cyclometalated Ir(III) complexes exhibit strong phosphorescence emission with lifetime of submicroseconds to several microseconds at room temperature. Their synthetic versatility enables broad control of physical properties, such as charge and lipophilicity, as well as emission colors. These favorable properties have motivated the use of Ir(III) complexes in luminescent bioimaging applications. This review examines the recent progress in the development of phosphorescent biolabels and sensors based on Ir(III) complexes. It begins with a brief introduction about the basic principles of the syntheses and photophysical processes of cyclometalated Ir(III) complexes. Focus is placed on illustrating the broad imaging utility of Ir(III) complexes. Phosphorescent labels illuminating intracellular organelles, including mitochondria, lysosomes, and cell membranes, are summarized. Ir(III) complexes capable of visualization of tumor spheroids and parasites are also introduced. Facile chemical modification of the cyclometalating ligands endows the Ir(III) complexes with strong sensing ability. Sensors of temperature, pH, CO2, metal ions, anions, biosulfur species, reactive oxygen species, peptides, and viscosity have recently been added to the molecular imaging tools. This diverse utility demonstrates the potential of phosphorescent Ir(III) complexes toward bioimaging applications.
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Remarkably flexible 2,2′:6′,2″-terpyridines and their group 8–10 transition metal complexes – Chemistry and applications. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214426] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Maekawa M, Terada K, Oda S, Sugimoto K, Okubo T, Kuroda-Sowa T. Syntheses and structural characterizations of mononuclear Ir(III) hydride complexes with 2,2′:6′,2″-terpyridine in the κ2N,N' and κ3N,N',N″ coordination modes. Inorganica Chim Acta 2021. [DOI: 10.1016/j.ica.2020.119962] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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New yellow-emitting iridium(III) complexes containing 2-phenyl-2H-indazole-based ligands for high efficient OLEDs with EQE over 25%. Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2020.119704] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Liu X, Hao H, Ge X, He X, Liu Y, Wang Y, Wang H, Shao M, Jing Z, Tian L, Liu Z. Triphenylamine-appended cyclometallated iridium(III) complexes: Preparation, photophysical properties and application in biology/luminescence imaging. J Inorg Biochem 2019; 199:110757. [DOI: 10.1016/j.jinorgbio.2019.110757] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 06/18/2019] [Accepted: 06/25/2019] [Indexed: 01/07/2023]
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Qu ZZ, Gao TB, Wen J, Rui K, Ma H, Cao DK. Cyclometalated Ir(iii) complexes [Ir(tpy)(bbibH2)Cl][PF6] and [Ir(tpy)(bmbib)Cl][PF6]: intramolecular π⋯π interactions leading to facile synthesis and enhanced luminescence. Dalton Trans 2018; 47:9779-9786. [DOI: 10.1039/c8dt01922c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Complexes [Ir(tpy)(bbibH2)Cl][PF6] (1·PF6) and [Ir(tpy)(bmbib)Cl][PF6] (2·PF6) show facile synthesis and enhanced luminescence due to intramolecular π⋯π interactions.
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Affiliation(s)
- Zhong-Ze Qu
- State Key Laboratory of Coordination Chemistry
- Coordination Chemistry Institute
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing 210093
| | - Tai-Bao Gao
- State Key Laboratory of Coordination Chemistry
- Coordination Chemistry Institute
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing 210093
| | - Jing Wen
- Key Laboratory of Mesoscopic Chemistry of MOE
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing 210093
- P. R. China
| | - Kai Rui
- State Key Laboratory of Coordination Chemistry
- Coordination Chemistry Institute
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing 210093
| | - Haibo Ma
- Key Laboratory of Mesoscopic Chemistry of MOE
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing 210093
- P. R. China
| | - Deng-Ke Cao
- State Key Laboratory of Coordination Chemistry
- Coordination Chemistry Institute
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing 210093
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Laha P, De U, Chandra F, Dehury N, Khullar S, Kim HS, Patra S. Alkyl chain-modified cyclometalated iridium complexes as tunable anticancer and imaging agents. Dalton Trans 2018; 47:15873-15881. [DOI: 10.1039/c8dt02461h] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Imidazole-based cyclometalated iridium complexes [1]+–[5]+ have been developed displaying alkyl chain length dependent anticancer activity and imaging property.
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Affiliation(s)
- Paltan Laha
- School of Basic Sciences
- Indian Institute of Technology Bhubaneswar
- Jatni-752050
- India
| | - Umasankar De
- Division of Toxicology
- School of Pharmacy
- Sungkyunkwan University
- Republic of Korea
| | - Falguni Chandra
- Department of Chemistry
- Indian Institute of Science Education and Research Bhopal
- Bhopal 462 066
- India
| | - Niranjan Dehury
- School of Basic Sciences
- Indian Institute of Technology Bhubaneswar
- Jatni-752050
- India
| | - Sadhika Khullar
- Department of Chemistry
- Dr. B. R. Ambedkar National Institute of Technology (NIT) Jalandhar
- Jalandhar – 144011
- India
| | - Hyung Sik Kim
- Division of Toxicology
- School of Pharmacy
- Sungkyunkwan University
- Republic of Korea
| | - Srikanta Patra
- School of Basic Sciences
- Indian Institute of Technology Bhubaneswar
- Jatni-752050
- India
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