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Sanz-Villafruela J, Bermejo-Casadesús C, Martínez-Alonso M, Moro A, Lima JC, Massaguer A, Espino G. Towards efficient Ir(III) anticancer photodynamic therapy agents by extending π-conjugation on N^N ligands. Dalton Trans 2024; 53:11393-11409. [PMID: 38899369 DOI: 10.1039/d4dt00390j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
In this work we disclose a new family of biscyclometallated Ir(III) complexes of the general formula [Ir(C^N)2(N^N)]Cl (IrL1-IrL5), where HC^N is 1-phenyl-β-carboline and N^N ligands (L1-L5) are different diimine ligands that differ from each other in the number of aromatic rings fused to the bipyridine scaffold. The photophysical properties of IrL1-IrL5 were thoroughly studied, and theoretical calculations were performed for a deeper comprehension of the respective variations along the series. All complexes exhibited high photostability under blue light irradiation. An increase in the number of aromatic rings led to a reduction in the HOMO-LUMO band gap causing a red-shift in the absorbance bands. Although all the complexes generated singlet oxygen (1O2) in aerated aqueous solutions through a photocatalytic process, IrL5 was by far the most efficient photosensitizer. Consequently, IrL5 was highly active in the photocatalytic oxidation of NADH. The formation of aggregates in DMSO at a high concentration (25 mM) was confirmed using different techniques, but was proved to be negligible in the concentration range of biological experiments. Moreover, ICP-MS studies proved that the cellular uptake of IrL2 and IrL3 is much better relative to that of IrL1, IrL4 and IrL5. The antiproliferative activity of IrL1-IrL5 was investigated in the dark and under blue light irradiation against different cancer cell lines. Complexes IrL1-IrL4 were found to be cytotoxic under dark conditions, while IrL5 turned out to be weakly cytotoxic. Despite the low cellular uptake of IrL5, this derivative exhibited a high increase of cytotoxicity upon blue light irradiation resulting in photocytotoxicity indexes (PI) up to 38. IrL1-IrL4 showed lower photocytotoxicity indexes ranging from 1.3 to 17.0. Haemolytic experiments corroborated the compatibility of our complexes with red blood cells. Confocal microscopy studies proved their accumulation in mitochondria, leading to mitochondrial membrane depolarization, and ruled out their localization in lysosomes. Overall, the mitochondria-targeted activity of IrL5, which inhibits considerably the viability of cancer cells upon blue light irradiation, allows us to outline this PS as a new alternative to traditional chemotherapeutic agents.
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Affiliation(s)
- Juan Sanz-Villafruela
- Universidad de Burgos, Departamento de Química, Facultad de Ciencias, Plaza Misael Bañuelos s/n, 09001, Burgos, Spain.
| | - Cristina Bermejo-Casadesús
- Universitat de Girona, Departament de Biologia, Facultat de Ciències, Maria Aurelia Capmany 40, 17003 Girona, Spain.
| | - Marta Martínez-Alonso
- Universidad de Burgos, Departamento de Química, Facultad de Ciencias, Plaza Misael Bañuelos s/n, 09001, Burgos, Spain.
| | - Artur Moro
- Universidade NOVA de Lisboa, LAQV-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, 2829-516 Caparica, Portugal
| | - João C Lima
- Universidade NOVA de Lisboa, LAQV-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, 2829-516 Caparica, Portugal
| | - Anna Massaguer
- Universitat de Girona, Departament de Biologia, Facultat de Ciències, Maria Aurelia Capmany 40, 17003 Girona, Spain.
| | - Gustavo Espino
- Universidad de Burgos, Departamento de Química, Facultad de Ciencias, Plaza Misael Bañuelos s/n, 09001, Burgos, Spain.
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Olumba ME, O'Donnell RM, Rohrabaugh TN, Teets TS. Triplet-Triplet Energy Transfer in Bis-Cyclometalated Iridium Complexes with Pyrene-Substituted Isocyanides. Inorg Chem 2023; 62:13702-13711. [PMID: 37579498 DOI: 10.1021/acs.inorgchem.3c00457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
Nonlinear optical (NLO) materials are able to modulate responses of electromagnetic radiation, leading to phenomena critical to modern telecommunications technologies. The last two decades have seen significant advances in the area of molecular nonlinear chromophores, particularly with respect to reverse-saturable absorption (RSA). Here, we introduce a strategy for intense excited-state absorption (ESA) that involves bis-cyclometalated iridium complexes with isocyanide ancillary ligands decorated with pyrene triplet acceptors. Upon excitation, the complexes undergo rapid triplet-triplet energy transfer (TTET) to the acceptor excited states. This report describes five bis-cyclometalated iridium complexes using two different pyrene-substituted isocyanides with the general formula [Ir(C^N)2(CNAr)2]PF6 (C^N = cyclometalating ligand, CNAr = isocyanide ancillary ligand: CNArpyr = 2,6-dimethyl-4-(1-pyrenyl)phenyl isocyanide, CNpyr = 1-pyrenyl isocyanide). The synthesized complexes were thoroughly characterized via 1H and 13C{1H} NMR spectroscopy, Fourier-transform Infrared spectroscopy, and electrospray ionization mass spectrometry. The excited states were evaluated with UV-vis absorption, steady-state and time-resolved photoluminescence, and transient absorption spectroscopy. Phosphorescence is completely quenched at room temperature, but in the solvent glass matrix at 77 K, there is luminescence originating from a π → π* triplet state on the pyrene moiety, abbreviated herein as 3pyrene. All five complexes display intense and long-lived ESA originating from the 3pyrene state. The localization of the ground-state absorption on the cyclometalating ligands and the excited-state absorption on the pyrene moiety allows for independent tuning of ground-state absorption (GSA) and ESA to optimize RSA and other NLO attributes.
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Affiliation(s)
- Morris E Olumba
- Department of Chemistry, University of Houston, 3585 Cullen Blvd., Room 112, Houston, Texas 77204-5003, United States
| | - Ryan M O'Donnell
- U.S. Army Combat Capabilities Development Command, Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783, United States
| | - Thomas N Rohrabaugh
- U.S. Army Combat Capabilities Development Command, Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783, United States
| | - Thomas S Teets
- Department of Chemistry, University of Houston, 3585 Cullen Blvd., Room 112, Houston, Texas 77204-5003, United States
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Olumba ME, O’Donnell RM, Rohrabaugh TN, Teets TS. Panchromatic Excited-State Absorption in Bis-Cyclometalated Iridium Isocyanide Complexes. Inorg Chem 2022; 61:19344-19353. [DOI: 10.1021/acs.inorgchem.2c03136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Morris E. Olumba
- Department of Chemistry, University of Houston, 3585 Cullen Blvd., Room 112, Houston, Texas77204-5003, United States
| | - Ryan M. O’Donnell
- U.S. Army Combat Capabilities Development Command, Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland20783, United States
| | - Thomas N. Rohrabaugh
- U.S. Army Combat Capabilities Development Command, Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland20783, United States
| | - Thomas S. Teets
- Department of Chemistry, University of Houston, 3585 Cullen Blvd., Room 112, Houston, Texas77204-5003, United States
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New iridium complexes(III) bearing 2-phenylimidazo[4,5-f][1,10]-phenanthroline ligand: Synthesis, characterization, electrochemical and photoluminescence studies. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2020.129415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Akhtar M, Arif AM, Ullah Khan S, Shan GG, Xu HL, Su ZM. Tuning the NLO response of bis-cyclometalated iridium( iii) complexes by modifying ligands: experimental and structural DFT analysis. NEW J CHEM 2021. [DOI: 10.1039/d1nj00114k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
DFT calculations have been carried out to investigate two synthesized iridium(iii) complexes with substituted Phbd (1-phenyl-2-(pyridin-2-yl)-1H-benzo[d]imidazole) and Crbd (9-(4-(2-(pyridin-2-yl)-1H-benzo[d]imidazol-1-yl)phenyl)-9H-carbazole) as ancillary ligands.
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Affiliation(s)
- Mansoor Akhtar
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun 130024
- People's Republic of China
| | - Ali Muhammad Arif
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun 130024
- People's Republic of China
| | - Shifa Ullah Khan
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun 130024
- People's Republic of China
| | - Guo-Gang Shan
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun 130024
- People's Republic of China
| | - Hong-liang Xu
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun 130024
- People's Republic of China
| | - Zhong-Min Su
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun 130024
- People's Republic of China
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Li H, Liu S, Lystrom L, Kilina S, Sun W. Improving triplet excited-state absorption and lifetime of cationic iridium(III) complexes by extending π-conjugation of the 2-(2-quinolinyl)quinoxaline ligand. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112609] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Synthesis, characterization, photo-and-electrochemical properties of cationic iridium(III) complexes by using 1,3,4-oxadiazole cyclometallating ligand. INORG CHEM COMMUN 2020. [DOI: 10.1016/j.inoche.2020.107980] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Liu B, Jabed MA, Kilina S, Sun W. Synthesis, Photophysics, and Reverse Saturable Absorption of trans-Bis-cyclometalated Iridium(III) Complexes (C^N^C)Ir(R-tpy) + (tpy = 2,2':6',2″-Terpyridine) with Broadband Excited-State Absorption. Inorg Chem 2020; 59:8532-8542. [PMID: 32497429 DOI: 10.1021/acs.inorgchem.0c00961] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Extending the bandwidth of triplet excited-state absorption in transition-metal complexes is appealing for developing broadband reverse saturable absorbers. Targeting this goal, five bis-terdentate iridium(III) complexes (Ir1-Ir5) bearing trans-bis-cyclometalating (C^N^C) and 4'-R-2,2':6',2″-terpyridine (4'-R-tpy) ligands were synthesized. The effects of the structural variation in cyclometalating ligands and substituents at the tpy ligand on the photophysics of these complexes have been systematically explored using spectroscopic methods (i.e., UV-vis absorption, emission, and transient absorption spectroscopy) and time-dependent density functional theory (TDDFT) calculations. All complexes exhibited intensely structured 1π,π* absorption bands at <400 nm and broad charge transfer (1CT)/1π,π* transitions at 400-600 nm. Ligand structural variations exerted a very small effect on the energies of the 1CT/1π,π* transitions; however, they had a significant effect on the molar extinction coefficients of these absorption bands. All complexes emitted featureless deep red phosphorescence in solutions at room temperature and gave broad-band and strong triplet excited-state absorption ranging from the visible to the near-infrared (NIR) spectral regions, with both originating from the 3π,π*/3CT states. Although alteration of the ligand structures influenced the emission energies slightly, these changes significantly affected the emission lifetimes and quantum yields, transient absorption spectral features, and the triplet excited-state quantum yields of the complexes. Except for Ir3, the other four complexes all manifested reverse saturable absorption (RSA) upon nanosecond laser pulse excitation at 532 nm, with the decreasing trend of RSA following Ir2 ≈ Ir4 > Ir1 > Ir5 > Ir3. The RSA trend corresponded well with the strength of the excited-state and ground-state absorption differences (ΔOD) at 532 nm for these complexes.
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Affiliation(s)
- Bingqing Liu
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota58108-6050, United States
| | - Mohammed A Jabed
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota58108-6050, United States
| | - Svetlana Kilina
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota58108-6050, United States
| | - Wenfang Sun
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota58108-6050, United States
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