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Gómez de Segura D, Giménez N, Rincón-Montón D, Moreno MT, Pichel JG, López IP, Lalinde E. A new family of luminescent [Pt(pbt) 2(C 6F 5)L] n+ ( n = 1, 0) complexes: synthesis, optical and cytotoxic studies. Dalton Trans 2023; 52:12390-12403. [PMID: 37594064 DOI: 10.1039/d3dt01759a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
Given the widely recognized bioactivity of 2-arylbenzothiazoles against tumor cells, we have designed a new family of luminescent heteroleptic pentafluorophenyl-bis(2-phenylbenzothiazolyl) PtIV derivatives, fac-[Pt(pbt)2(C6F5)L]n+ (n = 1, 0) [L = 4-Mepy 1, 4-pyridylbenzothiazole (pybt) 2, 4,4'-bipyridine (4,4'-bpy) 3, 1,2-bis-(4-pyridyl)ethylene (bpe) 4 (E/Z ratio: 90/10), 1,4-bis-(pyridyl)butadiyne (bpyb) 5, trifluoroacetate (-OCOCF3) 6] and a dinuclear complex [{Pt(pbt)2(C6F5)}2(μ-bpyb)](PF6)27, in which the trans ligand to the metalated C-(pbt) was varied to modify the optical properties and lipophilicity. Their photophysical properties were systematically studied through experimental and theoretical investigations, which were strongly dependent on the identity of the N-bonded ligand. Thus, complexes 1, 3 and 6 display, in different media, emission from the triplet excited states of primarily intraligand 3ILCT nature localized on the pbt ligand, while the emissions of 2, 5 and 7 were ascribed to a mixture of close 3IL'(N donor)/3ILCT(pbt) excited states, as supported by lifetime measurements and theoretical calculations. Irradiation of the initial E/Z mixture of 4 (15 min) led to a steady state composed of roughly 1 : 1.15 (E : Z) and this complex was not emissive at room temperature due to an enhanced intramolecular E to Z isomerization process of the 1,2-bis-(4-pyridyl)ethylene ligand. Complexes 1-3 and 6 showed excellent quantum yields for the generation of singlet oxygen in aerated MeCN solution with the values of ϕ(1O2) ranging from 0.66 to 0.86 using phenalenone as a reference. Cationic complexes 1-3 exhibited remarkable efficacy in the nanomolar range against A549 (lung carcinoma) and HeLa (cervix carcinoma) cell lines with notable selectivity relative to the non-tumorigenic BEAS-2B (bronchial epithelium) cells. In the A549 cell line, the neutral complex 6 showed low cytotoxicity (IC50: 29.40 μM) and high photocytotoxicity (IC50: 5.75) when cells were irradiated with blue light for 15 min. These complexes do not show evidence of DNA interaction.
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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.
| | - Nora Giménez
- Departamento de Química-Centro de Síntesis Química de La Rioja (CISQ), Universidad de La Rioja, 26006, Logroño, Spain.
| | - David Rincón-Montón
- 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.
| | - José G Pichel
- Lung Cancer and Respiratory Diseases Unit (CIBIR), Fundación Rioja Salud, 26006, Logroño, Spain.
- Spanish Biomedical Research Networking Centre in Respiratory Diseases (CIBERES), ISCIII, E-28029, Madrid, Spain
| | - Icíar P López
- Lung Cancer and Respiratory Diseases Unit (CIBIR), Fundación Rioja Salud, 26006, Logroño, Spain.
| | - Elena Lalinde
- Departamento de Química-Centro de Síntesis Química de La Rioja (CISQ), Universidad de La Rioja, 26006, Logroño, Spain.
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Poveda D, Vivancos Á, Bautista D, González-Herrero P. Photochemically Induced Cyclometalations at Simple Platinum(II) Precursors. Inorg Chem 2023; 62:6207-6213. [PMID: 37043617 PMCID: PMC10131227 DOI: 10.1021/acs.inorgchem.3c00688] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Photochemical cycloplatinations of 2-arylpyridines and related C∧N ligands, as well as terdentate heteroaromatic N∧N∧C, N∧C∧N, and N∧C∧C compounds, are demonstrated using (Bu4N)2[Pt2Cl6] or [PtCl2(NCPh)2] as precursors at room temperature. Mono- or bis-cyclometalated Pt(II) complexes with C∧N ligands are obtained depending on excitation wavelength and precursor. Monitoring experiments show that photoexcitation enables both the N-coordination and the subsequent C-H metalation. Photochemical synthetic protocols have been developed, which are advantageous with respect to the established thermal procedures and have allowed the synthesis of the first Pt(II) complexes with N∧C∧C ligands.
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Affiliation(s)
- Dionisio Poveda
- Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 19, 30100 Murcia, Spain
| | - Ángela Vivancos
- Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 19, 30100 Murcia, Spain
| | - Delia Bautista
- Área Científica y Técnica de Investigación, Universidad de Murcia, Campus de Espinardo, 21, 30100 Murcia, Spain
| | - Pablo González-Herrero
- Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 19, 30100 Murcia, Spain
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Scarpelli F, Ionescu A, Crispini A, Marino N, Di Maio G, La Deda M, Godbert N, Aiello I. Structural investigation of anionic cyclometalated Pt(II)-tetrabromocatecholate complexes: quasi-halogen bonding and elusive polymorphism at play. J COORD CHEM 2022. [DOI: 10.1080/00958972.2022.2132483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Francesca Scarpelli
- MAT-INLAB (Laboratorio di Materiali Molecolari Inorganici), Dipartimento di Chimica e Tecnologie Chimiche, Universitá della Calabria, Arcavacata di Rende, Cosenza, Italy
| | - Andreea Ionescu
- MAT-INLAB (Laboratorio di Materiali Molecolari Inorganici), Dipartimento di Chimica e Tecnologie Chimiche, Universitá della Calabria, Arcavacata di Rende, Cosenza, Italy
| | - Alessandra Crispini
- MAT-INLAB (Laboratorio di Materiali Molecolari Inorganici), Dipartimento di Chimica e Tecnologie Chimiche, Universitá della Calabria, Arcavacata di Rende, Cosenza, Italy
| | - Nadia Marino
- MAT-INLAB (Laboratorio di Materiali Molecolari Inorganici), Dipartimento di Chimica e Tecnologie Chimiche, Universitá della Calabria, Arcavacata di Rende, Cosenza, Italy
| | - Giuseppe Di Maio
- MAT-INLAB (Laboratorio di Materiali Molecolari Inorganici), Dipartimento di Chimica e Tecnologie Chimiche, Universitá della Calabria, Arcavacata di Rende, Cosenza, Italy
| | - Massimo La Deda
- MAT-INLAB (Laboratorio di Materiali Molecolari Inorganici), Dipartimento di Chimica e Tecnologie Chimiche, Universitá della Calabria, Arcavacata di Rende, Cosenza, Italy
- CNR NANOTEC-Istituto di Nanotecnologia U.O.S. Cosenza, Arcavacata di Rende, Cosenza, Italy
| | - Nicolas Godbert
- MAT-INLAB (Laboratorio di Materiali Molecolari Inorganici), Dipartimento di Chimica e Tecnologie Chimiche, Universitá della Calabria, Arcavacata di Rende, Cosenza, Italy
| | - Iolinda Aiello
- MAT-INLAB (Laboratorio di Materiali Molecolari Inorganici), Dipartimento di Chimica e Tecnologie Chimiche, Universitá della Calabria, Arcavacata di Rende, Cosenza, Italy
- CNR NANOTEC-Istituto di Nanotecnologia U.O.S. Cosenza, Arcavacata di Rende, Cosenza, Italy
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López-López JC, Bautista D, González-Herrero P. Luminescent halido(aryl) Pt(IV) complexes obtained via oxidative addition of iodobenzene or diaryliodonium salts to bis-cyclometalated Pt(II) precursors. Dalton Trans 2021; 50:13294-13305. [PMID: 34499066 DOI: 10.1039/d1dt02349g] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of bis-cyclometalated halido(aryl) Pt(IV) complexes [PtX(Ar)(C^N)2], with C^N = cyclometalated 4-(tert-butyl)-2-phenylpyridine (bppy), 2-(p-tolyl)pyridine (tpy), 2-(2-thienyl)pyridine (thpy), or 1-phenylisoquinoline (piq), X = I, Cl, or F, and Ar = Ph (for all C^N ligands) or t-BuPh (for C^N = tpy), and the photophysical properties of the chlorido and fluorido series is reported. The oxidative addition of iodobenzene to cis-[Pt(C^N)2] precursors is demonstrated to occur in MeCN under irradiation with visible light to give complexes [PtI(Ph)(C^N)2], presumably involving radical species that also produce the activation of the solvent to give cyanomethyl complexes [PtI(CH2CN)(C^N)2]. The introduction of an aryl ligand can also be achieved by reacting cis-[Pt(C^N)2] with (Ar2I)PF6 (Ar = Ph, t-BuPh), which affords cationic intermediates of the type [Pt(Ar)(C^N)2(NCMe)]+. The subsequent addition of an iodide or chloride salt gives the corresponding iodido- or chlorido(aryl) complexes. The fluorido(aryl) derivatives can be obtained from the iodido complexes by halide exchange using AgF. The chlorido- and fluorido(aryl) complexes display intense phosphorescence in deaerated CH2Cl2 solution and poly(methyl methacrylate) (PMMA) films at 298 K from triplet excited states primarily localized on the cyclometalated ligands (3LC) with a small MLCT admixture. Compared with the chlorido complexes, the fluorido derivatives consistently present significantly shorter emission lifetimes and higher radiative and nonradiative rate constants due to a greater MLCT contribution to the emissive state. In contrast, the introduction of the t-BuPh group did not induce significant changes in radiative rates with respect to the phenyl complexes.
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Affiliation(s)
- Juan-Carlos López-López
- Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 19, 30100 Murcia, Spain.
| | - Delia Bautista
- Área Científica y Técnica de Investigación, Universidad de Murcia, Campus de Espinardo, 21, 30100 Murcia, Spain
| | - Pablo González-Herrero
- Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 19, 30100 Murcia, Spain.
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Vivancos Á, Jiménez-García A, Bautista D, González-Herrero P. Strongly Luminescent Pt(IV) Complexes with a Mesoionic N-Heterocyclic Carbene Ligand: Tuning Their Photophysical Properties. Inorg Chem 2021; 60:7900-7913. [PMID: 33970000 PMCID: PMC8893362 DOI: 10.1021/acs.inorgchem.1c00410] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The synthesis, electrochemistry, and photophysical properties of a series of bis-cyclometalated Pt(IV) complexes that combine the mesoionic aryl-NHC ligand 4-butyl-3-methyl-1-phenyl-1H-1,2,3-triazol-5-ylidene (trz) with either 1-phenylpyrazole or 2-arylpyridine (C∧N) are reported. The complexes (OC-6-54)-[PtCl2(C∧N)(trz)] bearing cyclometalating 2-arylpyridines present phosphorescent emissions in the blue to yellow color range, which essentially arise from 3LC(C∧N) states, and reach quantum yields of ca. 0.3 in fluid solutions and almost unity in poly(methyl methacrylate) (PMMA) matrices at 298 K, thus representing a class of strong emitters with tunable properties. A systematic comparison with the homologous C2-symmetrical species (OC-6-33)-[PtCl2(C∧N)2], which contains two equal 2-arylpyridine ligands, shows that the introduction of a trz ligand leads to significantly lower nonradiative decay rates and higher quantum efficiencies. Computational calculations substantiate the effect of the carbene ligand, which raises the energy of dσ* orbitals in these derivatives and results in the higher energies of nonemissive deactivating 3LMCT states. In contrast, the isomers (OC-6-42)-[PtCl2(C∧N)(trz)] are not luminescent because they present a 3LMCT state as the lowest triplet.
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Affiliation(s)
- Ángela Vivancos
- Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo 19, 30100 Murcia, Spain
| | - Adrián Jiménez-García
- Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo 19, 30100 Murcia, Spain
| | - Delia Bautista
- Área Científica y Técnica de Investigación, Universidad de Murcia, Campus de Espinardo, 21, 30100 Murcia, Spain
| | - Pablo González-Herrero
- Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo 19, 30100 Murcia, Spain
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Ryabov AD. The Exchange of Cyclometalated Ligands. Molecules 2021; 26:E210. [PMID: 33401624 PMCID: PMC7795987 DOI: 10.3390/molecules26010210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 12/29/2020] [Accepted: 12/29/2020] [Indexed: 11/16/2022] Open
Abstract
Reactions of cyclometalated compounds are numerous. This account is focused on one of such reactions, the exchange of cyclometalated ligands, a reaction between a cyclometalated compound and an incoming ligand that replaces a previously cyclometalated ligand to form a new metalacycle: + H-C*~Z ⇄ + H-C~Y. Originally discovered for PdII complexes with Y/Z = N, P, S, the exchange appeared to be a mechanistically challenging, simple, and convenient routine for the synthesis of cyclopalladated complexes. Over four decades it was expanded to cyclometalated derivatives of platinum, ruthenium, manganese, rhodium, and iridium. The exchange, which is also questionably referred to as transcyclometalation, offers attractive synthetic possibilities and assists in disclosing key mechanistic pathways associated with the C-H bond activation by transition metal complexes and C-M bond cleavage. Both synthetic and mechanistic aspects of the exchange are reviewed and discussed.
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Affiliation(s)
- Alexander D Ryabov
- Institute for Green Science, Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
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