1
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Curtis CJ, Habenšus I, Conradie J, Bardin AA, Nannenga BL, Ghosh A, Tomat E. Gold Tripyrrindione: Redox Chemistry and Reactivity with Dichloromethane. Inorg Chem 2024; 63:17188-17197. [PMID: 39215706 DOI: 10.1021/acs.inorgchem.4c02903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
The identification of ligands that stabilize Au(III) centers has led to the isolation of complexes for applications in catalysis, gold-based therapeutics, and functional materials. Herein, we report the coordination of gold by tripyrrin-1,14-dione, a linear tripyrrole with the scaffold of naturally occurring metabolites of porphyrin-based protein cofactors (e.g., heme). Tripyrrindione H3TD2 binds Au(III) as a trianionic tridentate ligand to form square planar complex [Au(TD2)(H2O)], which features an adventitious aqua ligand. Two reversible ligand-based oxidations of this complex allow access to the other known redox states of the tripyrrindione framework. Conversely, (spectro)electrochemical measurements and DFT analysis indicate that the reduction of the complex is likely metal-based. The chemical reduction of [Au(TD2)(H2O)] leads to a reactive species that utilizes dichloromethane in the formation of a cyclometalated organo-Au(III) complex. Both the aqua and the organometallic Au(III) complexes were characterized in the solid state by microcrystal electron diffraction (MicroED) methods, which were critical for the analysis of the microcrystalline sample of the organo-gold species. Overall, this study illustrates the synthesis of Au(III) tripyrrindione as well as its redox profile and reactivity leading to gold alkylation chemistry.
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Affiliation(s)
- Clayton J Curtis
- Department of Chemistry and Biochemistry, The University of Arizona, 1306 E. University Blvd., Tucson, Arizona 85721, United States
| | - Iva Habenšus
- Department of Chemistry and Biochemistry, The University of Arizona, 1306 E. University Blvd., Tucson, Arizona 85721, United States
| | - Jeanet Conradie
- Department of Chemistry, University of the Free State, Bloemfontein 9300, Republic of South Africa
- Department of Chemistry, UiT─The Arctic University of Norway, Tromsø N-9037, Norway
| | - Andrey A Bardin
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, Arizona 85281, United States
- Chemical Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Brent L Nannenga
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, Arizona 85281, United States
- Chemical Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Abhik Ghosh
- Department of Chemistry, UiT─The Arctic University of Norway, Tromsø N-9037, Norway
| | - Elisa Tomat
- Department of Chemistry and Biochemistry, The University of Arizona, 1306 E. University Blvd., Tucson, Arizona 85721, United States
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2
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Kaur S, Das A, Velasco L, Sauvan M, Bera M, Ugale A, Charisiadis A, Moonshiram D, Paria S. Spectroscopic characterization and reactivity studies of a copper(II) iminoxyl radical complex. Chem Commun (Camb) 2024; 60:9934-9937. [PMID: 39072688 DOI: 10.1039/d4cc02922d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
A CuII complex (1) of a bis-pyridine-dioxime ligand and its one-electron oxidized analog (1-ox) were thoroughly characterized by various spectroscopic techniques, including X-ray absorption spectroscopy. 1-ox was found to be a CuII complex of a ligand iminoxyl radical and represents the first example of such a type. Reorganization energy (λ) of 2.12 eV was determined for the 1-ox/1 couple, which is considerably higher than the type 1 protein and synthetic CuIII/II(OH) complexes.
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Affiliation(s)
- Simarjeet Kaur
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
| | - Avijit Das
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
| | - Lucia Velasco
- Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Sor Juana Inés de la Cruz, 3, 28049, Madrid, Spain.
| | - Maxime Sauvan
- Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Sor Juana Inés de la Cruz, 3, 28049, Madrid, Spain.
| | - Moumita Bera
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
| | - Ashok Ugale
- Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Sor Juana Inés de la Cruz, 3, 28049, Madrid, Spain.
| | - Asterios Charisiadis
- Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Sor Juana Inés de la Cruz, 3, 28049, Madrid, Spain.
| | - Dooshaye Moonshiram
- Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Sor Juana Inés de la Cruz, 3, 28049, Madrid, Spain.
| | - Sayantan Paria
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
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3
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Ross DL, Jasniewski AJ, Ziller JW, Bominaar EL, Hendrich MP, Borovik AS. Modulation of the Bonding between Copper and a Redox-Active Ligand by Hydrogen Bonds and Its Effect on Electronic Coupling and Spin States. J Am Chem Soc 2024; 146:500-513. [PMID: 38150413 PMCID: PMC11160172 DOI: 10.1021/jacs.3c09983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
The exchange coupling of electron spins can strongly influence the properties of chemical species. The regulation of this type of electronic coupling has been explored within complexes that have multiple metal ions but to a lesser extent in complexes that pair a redox-active ligand with a single metal ion. To bridge this gap, we investigated the interplay among the structural and magnetic properties of mononuclear Cu complexes and exchange coupling between a Cu center and a redox-active ligand over three oxidation states. The computational analysis of the structural properties established a relationship between the complexes' magnetic properties and a bonding interaction involving a dx2-y2 orbital of the Cu ion and π orbital of the redox-active ligand that are close in energy. The additional bonding interaction affects the geometry around the Cu center and was found to be influenced by intramolecular H-bonds introduced by the external ligands. The ability to synthetically tune the d-π interactions using H-bonds illustrates a new type of control over the structural and magnetic properties of metal complexes.
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Affiliation(s)
- Dolores L Ross
- Department of Chemistry, 1102 Natural Science II, University of California, Irvine, California 92697, United States
| | - Andrew J Jasniewski
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697, United States
| | - Joseph W Ziller
- Department of Chemistry, 1102 Natural Science II, University of California, Irvine, California 92697, United States
| | - Emile L Bominaar
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Michael P Hendrich
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - A S Borovik
- Department of Chemistry, 1102 Natural Science II, University of California, Irvine, California 92697, United States
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4
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Kumar A, Thompson B, Gautam R, Tomat E, Huxter V. Temperature-Dependent Spin-Driven Dimerization Determines the Ultrafast Dynamics of a Copper(II)-Bound Tripyrrindione Radical. J Phys Chem Lett 2023; 14:11268-11273. [PMID: 38060441 DOI: 10.1021/acs.jpclett.3c02726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Radicals and other open-shell molecules play a central role in chemical transformations and redox chemistry. While radicals are often highly reactive, stable radical systems are desirable for a range of potential applications, ranging from materials chemistry and catalysis to spintronics and quantum information. Here we investigate the ultrafast properties of a stable radical system with temperature-dependent spin-tunable properties. This radical complex, Cu(II) hexaethyl tripyrrin-1,14-dione, accommodates unpaired electrons localized on both the copper metal center and the tripyrrolic ligand. The unusual combination of two unpaired electrons and high stability in this radical molecule enable switchable temperature-dependent spin coupling. Two-dimensional electronic spectroscopy measurements of Cu(II) hexaethyl tripyrrin-1,14-dione were collected at room temperature and at 77 K. At room temperature, the molecules are present as monomers and have short picosecond lifetimes. At 77 K, the molecules are present in a dimer form mediated by ferromagnetic and antiferromagnetic coupling. This reversible spin-driven dimerization changes the optical properties of the system, generating long-lived excitonic states.
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Affiliation(s)
- Anshu Kumar
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
- Department of Physics, University of Arizona, Tucson, Arizona 85721, United States
| | - Benjamin Thompson
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
- Department of Optical Sciences, University of Arizona, Tucson, Arizona 85721, United States
| | - Ritika Gautam
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Elisa Tomat
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Vanessa Huxter
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
- Department of Physics, University of Arizona, Tucson, Arizona 85721, United States
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5
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Tomat E, Curtis CJ, Astashkin AV, Conradie J, Ghosh A. Multicenter interactions and ligand field effects in platinum(II) tripyrrindione radicals. Dalton Trans 2023; 52:6559-6568. [PMID: 37185585 DOI: 10.1039/d3dt00894k] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The tripyrrin-1,14-dione biopyrrin, which shares the scaffold of several naturally occurring heme metabolites, is a redox-active platform for metal coordination. We report the synthesis of square planar platinum(II) tripyrrindiones, in which the biopyrrin binds as a tridentate radical and the fourth coordination position is occupied by either aqua or tert-butyl isocyanide ligands. These complexes are stable through chromatographic purification and exposure to air. Electron paramagnetic resonance (EPR) data and density functional theory (DFT) analysis confirm that the spin density is located predominantly on the tripyrrindione ligand. Pancake bonding in solution between the Pt(II) tripyrrindione radicals leads to the formation of diamagnetic π dimers at low temperatures. The identity of the monodentate ligand (i.e., aqua vs. isocyanide) affects both the thermodynamic parameters of dimerization and the tripyrrindione-based redox processes in these complexes. Isolation and structural characterization of the oxidized complexes revealed stacking of the diamagnetic tripyrrindiones in the solid state as well as a metallophilic Pt(II)-Pt(II) contact in the case of the aqua complex. Overall, the properties of Pt(II) tripyrrindiones, including redox potentials and intermolecular interactions in solution and in the solid state, are modulated through easily accessible changes in the redox state of the biopyrrin ligand or the nature of the monodentate ligand.
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Affiliation(s)
- Elisa Tomat
- Department of Chemistry and Biochemistry, The University of Arizona, 1306 E. University Blvd., Tucson, AZ 85721-0041, USA.
| | - Clayton J Curtis
- Department of Chemistry and Biochemistry, The University of Arizona, 1306 E. University Blvd., Tucson, AZ 85721-0041, USA.
| | - Andrei V Astashkin
- Department of Chemistry and Biochemistry, The University of Arizona, 1306 E. University Blvd., Tucson, AZ 85721-0041, USA.
| | - Jeanet Conradie
- Department of Chemistry, University of the Free State, Bloemfontein 9300, Republic of South Africa
- Department of Chemistry, UiT - The Arctic University of Norway, N-9037 Tromsø, Norway.
| | - Abhik Ghosh
- Department of Chemistry, UiT - The Arctic University of Norway, N-9037 Tromsø, Norway.
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6
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Cho B, Swain A, Gautam R, Tomat E, Huxter VM. Time-resolved dynamics of stable open- and closed-shell neutral radical and oxidized tripyrrindione complexes. Phys Chem Chem Phys 2022; 24:15718-15725. [PMID: 35730195 DOI: 10.1039/d2cp00632d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Stable open- and closed-shell Pd(II) and Cu(II) complexes of hexaethyl tripyrrin-1,14-dione (TD1) produce triplet, doublet or singlet states depending on the metal center and the redox state of the ligand. Pd(II) and Cu(II) form neutral TD1 complexes featuring ligand-based radicals, thus resulting in doublet and triplet states, respectively. The reversible one-electron oxidation of the complexes removes an unpaired electron from the ligand, generating singlet and doublet states. The optical properties and time-resolved dynamics of these systems are studied here using steady-state and ultrafast transient absorption (pump-probe) measurements. Fast relaxation with recovery of the ground state in tens of picoseconds is observed for the copper neutral radical and oxidized complexes as well as for the palladium neutral radical complex. Significantly longer timescales are observed for the oxidized palladium complex. The ability to tune the overall spin state of the complexes through their stable open-shell configurations as well as the reversible redox activity of the tripyrrolic systems makes them particularly interesting for catalytic applications as well as exploring magnetism and conductivity properties.
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Affiliation(s)
- Byungmoon Cho
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, 85721, USA.
| | - Alicia Swain
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, 85721, USA.
| | - Ritika Gautam
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, 85721, USA.
| | - Elisa Tomat
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, 85721, USA.
| | - Vanessa M Huxter
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona, 85721, USA. .,Department of Physics, The University of Arizona, Tucson, Arizona, 85721, USA
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7
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Tomat E, Curtis CJ. Biopyrrin Pigments: From Heme Metabolites to Redox-Active Ligands and Luminescent Radicals. Acc Chem Res 2021; 54:4584-4594. [PMID: 34870973 DOI: 10.1021/acs.accounts.1c00613] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Redox-active ligands in coordination chemistry not only modulate the reactivity of the bound metal center but also serve as electron reservoirs to store redox equivalents. Among many applications in contemporary chemistry, the scope of redox-active ligands in biology is exemplified by the porphyrin radicals in the catalytic cycles of multiple heme enzymes (e.g., cytochrome P450, catalase) and the chlorophyll radicals in photosynthetic systems. This Account reviews the discovery of two redox-active ligands inspired by oligopyrrolic fragments found in biological settings as products of heme metabolism.Linear oligopyrroles, in which pyrrole heterocycles are linked by methylene or methine bridges, are ubiquitous in nature as part of the complex, multistep biosynthesis and degradation of hemes and chlorophylls. Bile pigments, such as biliverdin and bilirubin, are common and well-studied tetrapyrroles with characteristic pyrrolin-2-one rings at both terminal positions. The coordination chemistry of these open-chain pigments is less developed than that of porphyrins and other macrocyclic oligopyrroles; nevertheless, complexes of biliverdin and its synthetic analogs have been reported, along with fluorescent zinc complexes of phytobilins employed as bioanalytical tools. Notably, linear conjugated tetrapyrroles inherit from porphyrins the ability to stabilize unpaired electrons within their π system. The isolated complexes, however, present helical structures and generally limited stability.Smaller biopyrrins, which feature three or two pyrrole rings and the characteristic oxidized termini, have been known for several decades following their initial isolation as urinary pigments and heme metabolites. Although their coordination chemistry has remained largely unexplored, these compounds are structurally similar to the well-established tripyrrin and dipyrrin ligands employed in a broad variety of metal complexes. In this context, our study of the coordination chemistry of tripyrrin-1,14-dione and dipyrrin-1,9-dione was motivated by the potential to retain on these compact, versatile platforms the reversible ligand-based redox chemistry of larger tetrapyrrolic systems.The tripyrrindione ligand coordinates several divalent transition metals (i.e., Pd(II), Ni(II) Cu(II), Zn(II)) to form neutral complexes in which an unpaired electron is delocalized over the conjugated π system. These compounds, which are stable at room temperature and exposed to air, undergo reversible one-electron processes to access different redox states of the ligand system without affecting the oxidation state and coordination geometry of the metal center. We also characterized ligand-based radicals on the dipyrrindione platform in both homoleptic and heteroleptic complexes. In addition, this study documented noncovalent interactions (e.g., interligand hydrogen bonds with the pyrrolinone carbonyls, π-stacking of ligand-centered radicals) as important aspects of this coordination chemistry. Furthermore, the fluorescence of the zinc-bound tripyrrindione radical and the redox-switchable emission of a dipyrrindione BODIPY-type fluorophore showcased the potential interplay of redox chemistry and luminescence in these compounds. Supported by computational analyses, the portfolio of properties revealed by this investigation takes the tripyrrindione and dipyrrindione motifs of heme metabolites to the field of redox-active ligands, where they are positioned to offer new opportunities for catalysis, sensing, supramolecular systems, and functional materials.
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Affiliation(s)
- Elisa Tomat
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721-0041, United States
| | - Clayton J. Curtis
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721-0041, United States
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8
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Bischoff F, Riss A, Michelitsch GS, Ducke J, Barth JV, Reuter K, Auwärter W. Surface-Mediated Ring-Opening and Porphyrin Deconstruction via Conformational Distortion. J Am Chem Soc 2021; 143:15131-15138. [PMID: 34472340 DOI: 10.1021/jacs.1c05348] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The breakdown of macrocyclic compounds is of utmost importance in manifold biological and chemical processes, usually proceeding via oxygenation-induced ring-opening reactions. Here, we introduce a surface chemical route to selectively break a prototypical porphyrin species, cleaving off one pyrrole unit and affording a tripyrrin derivative. This pathway, operational in an ultrahigh vacuum environment at moderate temperature is enabled by a distinct molecular conformation achieved via the specific interaction between the porphyrin and its copper support. We provide an atomic-level characterization of the surface-anchored tripyrrin, its reaction intermediates, and byproducts by bond-resolved atomic force microscopy, unequivocally identifying the molecular skeletons. The ring-opening is rationalized by the distortion reducing the macrocycle's stability. Our findings open a route to steer ring-opening reactions by conformational design and to study intriguing tetrapyrrole catabolite analogues on surfaces.
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Affiliation(s)
- Felix Bischoff
- Physics Department E20, Technical University of Munich, James-Franck Str. 1, 85748 Garching, Germany
| | - Alexander Riss
- Physics Department E20, Technical University of Munich, James-Franck Str. 1, 85748 Garching, Germany
| | - Georg S Michelitsch
- Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 5, 85748 Garching, Germany
| | - Jacob Ducke
- Physics Department E20, Technical University of Munich, James-Franck Str. 1, 85748 Garching, Germany
| | - Johannes V Barth
- Physics Department E20, Technical University of Munich, James-Franck Str. 1, 85748 Garching, Germany
| | - Karsten Reuter
- Theoretical Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstr. 5, 85748 Garching, Germany.,Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin-Dahlem, Germany
| | - Willi Auwärter
- Physics Department E20, Technical University of Munich, James-Franck Str. 1, 85748 Garching, Germany
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Curtis CJ, Astashkin AV, Conradie J, Ghosh A, Tomat E. Ligand-Centered Triplet Diradical Supported by a Binuclear Palladium(II) Dipyrrindione. Inorg Chem 2021; 60:12457-12466. [PMID: 34347474 PMCID: PMC8389801 DOI: 10.1021/acs.inorgchem.1c01691] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Oligopyrroles
form
a versatile class of redox-active ligands and
electron reservoirs. Although the stabilization of radicals within
oligopyrrolic π systems is more common for macrocyclic ligands,
bidentate dipyrrindiones are emerging as compact platforms for one-electron
redox chemistry in transition-metal complexes. We report the synthesis
of a bis(aqua) palladium(II) dipyrrindione complex and its deprotonation-driven
dimerization to form a hydroxo-bridged binuclear complex in the presence
of water or triethylamine. Electrochemical, spectroelectrochemical,
and computational analyses of the binuclear complex indicate the accessibility
of two quasi-reversible ligand-centered reduction processes. The product
of a two-electron chemical reduction by cobaltocene was isolated and
characterized. In the solid state, this cobaltocenium salt features
a folded dianionic complex that maintains the hydroxo bridges between
the divalent palladium centers. X-band and Q-band EPR spectroscopic
experiments and DFT computational analysis allow assignment of the
dianionic species as a diradical with spin density almost entirely
located on the two dipyrrindione ligands. As established from the
EPR temperature dependence, the associated exchange coupling is weak
and antiferromagnetic (J ≈ −2.5 K),
which results in a predominantly triplet state at the temperatures
at which the measurements have been performed. The coordination and redox chemistry of the dipyrrindione
scaffold, which is found in several heme metabolites, is investigated
in heteroleptic palladium(II) complexes. The bis(aqua) complex undergoes
a deprotonation-driven dimerization to form a hydroxo-bridged binuclear
species. Crystallographic, electrochemical, and spectroscopic data,
as well as computational analysis, demonstrate that a two-electron
reduction of the binuclear complex leads to a diradical dianion with
spin density delocalized over the two dipyrrindione ligands.
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Affiliation(s)
- Clayton J Curtis
- Department of Chemistry and Biochemistry, The University of Arizona, 1306 East University Blvd., Tucson, Arizona 85721, United States
| | - Andrei V Astashkin
- Department of Chemistry and Biochemistry, The University of Arizona, 1306 East University Blvd., Tucson, Arizona 85721, United States
| | - Jeanet Conradie
- Department of Chemistry, University of the Free State, P.O. Box 339, Bloemfontein 9300, Republic of South Africa.,Department of Chemistry, UiT - The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Abhik Ghosh
- Department of Chemistry, UiT - The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Elisa Tomat
- Department of Chemistry and Biochemistry, The University of Arizona, 1306 East University Blvd., Tucson, Arizona 85721, United States
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10
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Expanding the eggshell colour gamut: uroerythrin and bilirubin from tinamou (Tinamidae) eggshells. Sci Rep 2020; 10:11264. [PMID: 32647200 PMCID: PMC7347609 DOI: 10.1038/s41598-020-68070-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 06/01/2020] [Indexed: 11/10/2022] Open
Abstract
To date, only two pigments have been identified in avian eggshells: rusty-brown protoporphyrin IX and blue-green biliverdin IXα. Most avian eggshell colours can be produced by a mixture of these two tetrapyrrolic pigments. However, tinamou (Tinamidae) eggshells display colours not easily rationalised by combination of these two pigments alone, suggesting the presence of other pigments. Here, through extraction, derivatization, spectroscopy, chromatography, and mass spectrometry, we identify two novel eggshell pigments: yellow–brown tetrapyrrolic bilirubin from the guacamole-green eggshells of Eudromia elegans, and red–orange tripyrrolic uroerythrin from the purplish-brown eggshells of Nothura maculosa. Both pigments are known porphyrin catabolites and are found in the eggshells in conjunction with biliverdin IXα. A colour mixing model using the new pigments and biliverdin reproduces the respective eggshell colours. These discoveries expand our understanding of how eggshell colour diversity is achieved. We suggest that the ability of these pigments to photo-degrade may have an adaptive value for the tinamous.
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Imafuku M, Oki S, Suzuki M. Bromine‐Terminated
β
‐Alkyl‐Substituted Tripyrrin: Reactivity, Coordination Ability, and Role as Extendable Acyclic Oligo‐Pyrrole Ligand. ChemistrySelect 2020. [DOI: 10.1002/slct.202001412] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Masato Imafuku
- Interdisciplinary Graduate School of Science and EngineeringShimane University 1060 Nishikawatsu-cho Matsue, Shimane 690-8504 Japan
| | - Setsuna Oki
- Interdisciplinary Graduate School of Science and EngineeringShimane University 1060 Nishikawatsu-cho Matsue, Shimane 690-8504 Japan
| | - Masaaki Suzuki
- Interdisciplinary Graduate School of Science and EngineeringShimane University 1060 Nishikawatsu-cho Matsue, Shimane 690-8504 Japan
- Graduate School of Natural Science and TechnologyShimane University 1060 Nishikawatsu-cho, Matsue Shimane 690-8504 Japan
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12
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Curtis CJ, Tomat E. Heteroleptic palladium(II) complexes of dipyrrin-1,9-dione supported by intramolecular hydrogen bonding. J PORPHYR PHTHALOCYA 2020. [DOI: 10.1142/s1088424619501062] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The dipyrrin-1,9-dione framework, which is characteristic of the propentdyopent pigments deriving from heme metabolism, coordinates metal ions as monoanionic bidentate donors. The resulting analogs of dipyrrinato complexes undergo reversible ligand-based reductions, thus showcasing the ability of the dipyrrindione scaffold to act as an electron reservoir. Herein we report the synthesis and characterization of three heteroleptic palladium complexes of the redox-active dipyrrindione ligand. Primary amines were chosen as additional ligands so as to assemble complexes of planar geometries with complementary interligand hydrogen-bonding. Full chemical characterization confirms the hydrogen bonding interactions between the primary amine ligands and the acceptor carbonyl groups on the dipyrrolic ligand. The resulting heteroleptic compounds display reversible one-electron reduction events that are centered on the dipyrrindione ligand as revealed by voltammetry and spectroelectrochemistry data. Within these planar Pd(II) complexes, the propentdyopent motif therefore combines reversible ligand-based redox chemistry with interligand hydrogen bonding in the primary coordination sphere of the metal center.
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Affiliation(s)
- Clayton J. Curtis
- The University of Arizona, Department of Chemistry and Biochemistry, 1306 E. University Blvd., Tucson AZ 85721, USA
| | - Elisa Tomat
- The University of Arizona, Department of Chemistry and Biochemistry, 1306 E. University Blvd., Tucson AZ 85721, USA
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13
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Abstract
Propentdyopents are naturally occurring dipyrroles deriving from the metabolism of heme and characterized by a dipyrrin-1,9-dione motif. The unusual name propentdyopent is due to the first colorimetric method (the Stokvis reaction) for the detection of these compounds, which were initially isolated from urine samples. Upon reduction in alkaline solutions, they produced red species that were termed pentdyopents to describe with Greek numerals their absorption maximum (525 nm) in the visible range. The precursors to the red pentdyopents were thus indicated as propentdyopents.Over the course of several decades, these dipyrrolic compounds have appeared in several studies of human physiology, typically associated to conditions of abnormal heme metabolism and/or oxidative stress. Concurrently, synthetic investigations have confirmed their chemical structure, reactivity, and ability to coordinate metals as bidentate monoanionic ligands. Notably, the planar dipyrrindione platform can undergo reversible one-electron redox processes and thereby act as an electron reservoir in metal complexes. In combination with the documented ability of the carbonyl groups to act as hydrogen-bonding acceptors, the coordination chemistry of propentdyopents could lead to new applications for this old class of pigments. Furthermore, the observation of these pigments in several clinical contexts could potentially delineate a role of propentdyopents as diagnostic biomarkers. This mini-review summarizes both the chemistry and biology of propentdyopents while highlighting the ample space for new discoveries.
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Affiliation(s)
- Elisa Tomat
- The University of Arizona, Department of Chemistry and Biochemistry, 1306 E. University Blvd., Tucson AZ 85721, USA
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14
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Recent advances in the chemistry of group 9—Pincer organometallics. ADVANCES IN ORGANOMETALLIC CHEMISTRY 2020. [DOI: 10.1016/bs.adomc.2019.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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15
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Domergue J, Pécaut J, Proux O, Lebrun C, Gateau C, Le Goff A, Maldivi P, Duboc C, Delangle P. Mononuclear Ni(II) Complexes with a S3O Coordination Sphere Based on a Tripodal Cysteine-Rich Ligand: pH Tuning of the Superoxide Dismutase Activity. Inorg Chem 2019; 58:12775-12785. [PMID: 31545024 DOI: 10.1021/acs.inorgchem.9b01686] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The superoxide dismutase (SOD) activity of mononuclear NiII complexes, whose structures are inspired by the NiSOD, has been investigated. They have been designed with a sulfur-rich pseudopeptide ligand, derived from nitrilotriacetic acid (NTA), where the three acid functions are grafted with cysteines (L3S). Two mononuclear complexes, which exist in pH-dependent proportions, have been fully characterized by a combination of spectroscopic techniques including 1H NMR, UV-vis, circular dichroism, and X-ray absorption spectroscopy, together with theoretical calculations. They display similar square-planar S3O coordination, with the three thiolates of the three cysteine moieties from L3S coordinated to the NiII ion, together with either a water molecule at physiological pH, as [NiL3S(OH2)]-, or a hydroxo ion in more basic conditions, as [NiL3S(OH)]2-. The 1H NMR study has revealed that contrary to the hydroxo ligand, the bound water molecule is labile. The cyclic voltammogram of both complexes displays an irreversible one-electron oxidation process assigned to the NiII/NiIII redox system with Epa = 0.48 and 0.31 V versus SCE for NiL3S(OH2) and NiL3S(OH), respectively. The SOD activity of both complexes has been tested. On the basis of the xanthine oxidase assay, an IC50 of about 1 μM has been measured at pH 7.4, where NiL3S(OH2) is mainly present (93% of the NiII species), while the IC50 is larger than 100 μM at pH 9.6, where NiL3S(OH) is the major species (92% of the NiII species). Interestingly, only NiL3S(OH2) displays SOD activity, suggesting that the presence of a labile ligand is required. The SOD activity has been also evaluated under catalytic conditions at pH 7.75, where the ratio between NiL3S(OH2)/ NiL3S(OH) is about (86:14), and a rate constant, kcat = 1.8 × 105 M-1 s-1, has been measured. NiL3S(OH2) is thus the first low-molecular weight, synthetic, bioinspired Ni complex that displays catalytic SOD activity in water at physiological pH, although it does not contain any N-donor ligand in its first coordination sphere, as in the NiSOD. Overall, the data show that a key structural feature is the presence of a labile ligand in the coordination sphere of the NiII ion.
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Affiliation(s)
- Jérémy Domergue
- Univ. Grenoble Alpes, CNRS, DCM , 38000 Grenoble , France.,Univ. Grenoble Alpes, CEA, CNRS, IRIG, SYMMES , 38000 Grenoble , France
| | - Jacques Pécaut
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, SYMMES , 38000 Grenoble , France
| | - Olivier Proux
- Univ. Grenoble Alpes, CNRS, OSUG , 38000 Grenoble , France
| | - Colette Lebrun
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, SYMMES , 38000 Grenoble , France
| | - Christelle Gateau
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, SYMMES , 38000 Grenoble , France
| | - Alan Le Goff
- Univ. Grenoble Alpes, CNRS, DCM , 38000 Grenoble , France
| | - Pascale Maldivi
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, SYMMES , 38000 Grenoble , France
| | - Carole Duboc
- Univ. Grenoble Alpes, CNRS, DCM , 38000 Grenoble , France
| | - Pascale Delangle
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, SYMMES , 38000 Grenoble , France
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16
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Kupietz K, Białek MJ, Hassa K, Białońska A, Latos-Grażyński L. Oxygenation of Phenanthriporphyrin and Copper(III) Phenanthriporphyrin: An Efficient Route to Phenanthribilinones. Inorg Chem 2019; 58:12446-12456. [PMID: 31454233 DOI: 10.1021/acs.inorgchem.9b02183] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Photooxidation of copper(III) 5,6-dimethoxyphenathriporphyrin and copper(III) 5,6-dioxophenanthriporphyrin, which contain phenanthrene or dioxophenathrene moieties built into the macrocyclic frameworks, resulted in the regioselective cleavage that afforded organometallic copper(III) complexes of open-chain phenanthribilinone-type acyclic ligands terminated by carbonyl groups. The copper(III) coordinates two carbon atoms of phenantherene (dioxophenanthrene) and two nitrogen atoms of pyrrole and pyrrolone units, preserving the donor sets of the paternal complexes. The primary dioxygen attack is located at the meso carbon atom adjacent to the phenanthrene moiety. Demetalation of copper(III) 21-benzoyl-phenanthribilin-1-one and copper(III) 21-benzoyl-dioxophenanthribilin-1-one yielded mainly two diastereomers [15Z, 20E] and [15Z, 20Z], which differ in the configurations at two Cα-Cmeso double bonds. The regioselectivity of the cleavage, detected in the course of experimental studies, has been substantiated by DFT investigations. The regioselective cleavage of 5,6-dimethoxyphenanthriporphyrin in reaction with basic iron(III) acetate was detected, providing the synthetically efficient methodology to produce 21-benzoyl-dioxophenanthribilin-1-one.
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Affiliation(s)
- Kamil Kupietz
- Department of Chemistry , University of Wrocław , F. Joliot-Curie 14 , 50-383 Wrocław , Poland
| | - Michał J Białek
- Department of Chemistry , University of Wrocław , F. Joliot-Curie 14 , 50-383 Wrocław , Poland
| | - Karolina Hassa
- Department of Chemistry , University of Wrocław , F. Joliot-Curie 14 , 50-383 Wrocław , Poland
| | - Agata Białońska
- Department of Chemistry , University of Wrocław , F. Joliot-Curie 14 , 50-383 Wrocław , Poland
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17
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Swain A, Cho B, Gautam R, Curtis CJ, Tomat E, Huxter V. Ultrafast Dynamics of Tripyrrindiones in Solution Mediated by Hydrogen-Bonding Interactions. J Phys Chem B 2019; 123:5524-5535. [DOI: 10.1021/acs.jpcb.9b01916] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Alicia Swain
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Byungmoon Cho
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Ritika Gautam
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Clayton J. Curtis
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Elisa Tomat
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Vanessa Huxter
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
- Department of Physics, University of Arizona, Tucson, Arizona 85721, United States
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18
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Gautam R, Petritis SJ, Tomat E. Redox-Switchable Cyan Fluorescence of a BODIPY Analog Inspired by Propentdyopent Pigments. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201800941] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Ritika Gautam
- Department of Chemistry and Biochemistry; The University of Arizona; 1306 E. University Blvd. 85721 Tucson AZ USA
| | - Steven J. Petritis
- Department of Chemistry and Biochemistry; The University of Arizona; 1306 E. University Blvd. 85721 Tucson AZ USA
| | - Elisa Tomat
- Department of Chemistry and Biochemistry; The University of Arizona; 1306 E. University Blvd. 85721 Tucson AZ USA
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19
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Gautam R, Petritis SJ, Astashkin AV, Tomat E. Paramagnetism and Fluorescence of Zinc(II) Tripyrrindione: A Luminescent Radical Based on a Redox-Active Biopyrrin. Inorg Chem 2018; 57:15240-15246. [PMID: 30418755 DOI: 10.1021/acs.inorgchem.8b02532] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ability of bilins and other biopyrrins to form fluorescent zinc complexes has been known for more than a century; however, the exact identity of the emissive species remains uncertain in many cases. Herein, we characterize the hitherto elusive zinc complex of tripyrrin-1,14-dione, an analogue of several orange urinary pigments. As previously observed for its Pd(II), Cu(II), and Ni(II) complexes, tripyrrindione binds Zn(II) as a dianionic radical and forms a paramagnetic complex carrying an unpaired electron on the ligand π-system. This species is stable at room temperature and undergoes quasi-reversible ligand-based redox chemistry. Although the complex is isolated as a coordination dimer in the solid state, optical absorption and electron paramagnetic resonance spectroscopic studies indicate that the monomer is prevalent in a tetrahydrofuran solution. The paramagnetic Zn(II) tripyrrindione complex is brightly fluorescent (λabs = 599 nm, λem = 644 nm, ΦF = 0.23 in THF), and its study provides a molecular basis for the observation, made over several decades since the 1930s, of fluorescent behavior of tripyrrindione pigments in the presence of zinc salts. The zinc-bound tripyrrindione radical is thus a new addition to the limited number of stable radicals that are fluorescent at room temperature.
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Affiliation(s)
- Ritika Gautam
- Department of Chemistry and Biochemistry , The University of Arizona , Tucson , Arizona 85721 , United States
| | - Steven J Petritis
- Department of Chemistry and Biochemistry , The University of Arizona , Tucson , Arizona 85721 , United States
| | - Andrei V Astashkin
- Department of Chemistry and Biochemistry , The University of Arizona , Tucson , Arizona 85721 , United States
| | - Elisa Tomat
- Department of Chemistry and Biochemistry , The University of Arizona , Tucson , Arizona 85721 , United States
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20
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Ooi S, Shimizu D, Furukawa K, Tanaka T, Osuka A. Stable Face-to-Face Singlet Diradicaloids: Triply Linked Corrole Dimer Gallium(III) Complexes with Two μ
-Hydroxo-Bridges. Angew Chem Int Ed Engl 2018; 57:14916-14920. [DOI: 10.1002/anie.201810200] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Shota Ooi
- Department of Chemistry; Graduate School of Science; Kyoto University; Sakyo-ku Kyoto 606-8502 Japan
| | - Daiki Shimizu
- Department of Chemistry; Graduate School of Science; Kyoto University; Sakyo-ku Kyoto 606-8502 Japan
| | - Ko Furukawa
- Center for Coordination of Research Facilities; Niigata University; Nishi-ku Niigata 950-2181 Japan
| | - Takayuki Tanaka
- Department of Chemistry; Graduate School of Science; Kyoto University; Sakyo-ku Kyoto 606-8502 Japan
| | - Atsuhiro Osuka
- Department of Chemistry; Graduate School of Science; Kyoto University; Sakyo-ku Kyoto 606-8502 Japan
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21
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Ooi S, Shimizu D, Furukawa K, Tanaka T, Osuka A. Stable Face-to-Face Singlet Diradicaloids: Triply Linked Corrole Dimer Gallium(III) Complexes with Two μ
-Hydroxo-Bridges. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201810200] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Shota Ooi
- Department of Chemistry; Graduate School of Science; Kyoto University; Sakyo-ku Kyoto 606-8502 Japan
| | - Daiki Shimizu
- Department of Chemistry; Graduate School of Science; Kyoto University; Sakyo-ku Kyoto 606-8502 Japan
| | - Ko Furukawa
- Center for Coordination of Research Facilities; Niigata University; Nishi-ku Niigata 950-2181 Japan
| | - Takayuki Tanaka
- Department of Chemistry; Graduate School of Science; Kyoto University; Sakyo-ku Kyoto 606-8502 Japan
| | - Atsuhiro Osuka
- Department of Chemistry; Graduate School of Science; Kyoto University; Sakyo-ku Kyoto 606-8502 Japan
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22
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Umetani M, Tanaka T, Osuka A. Conjugated double helices via self-dimerization of α,α'-dianilinotripyrrins. Chem Sci 2018; 9:6853-6859. [PMID: 30310618 PMCID: PMC6114996 DOI: 10.1039/c8sc02739k] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 07/16/2018] [Indexed: 01/25/2023] Open
Abstract
A new motif for artificial double helices was developed on the basis of α,α'-disubstituted tripyrrin. α,α'-Dibromotripyrrin 3 was prepared by gentle bromination at the pyrrolic α-positions of 5,10-diphenyltripyrrane followed by oxidation with DDQ. Nucleophilic substitution reactions of 3 with anilines proceeded efficiently to furnish a series of α,α'-dianilinotripyrrins 4-11, which displayed monomeric and dimeric forms depending upon the solvent used for crystallization and the structures of the substituted anilines. Dimeric forms show double helical structures with smooth π-conjugation as indicated by their absorption spectra. van't-Hoff plot analyses revealed that the dimerizations in CDCl3 are enthalpy-driven. Larger association constants of the dimerization are attained for 3,5-di-t-butylanilino- and 3,5-bis(trifluoromethyl)anilino-substituted tripyrrins (7 and 8) via additional multiple intermolecular interactions. In a nonpolar and aprotic solvent, tripyrrins (9 and 10) bearing bulkier 1-naphthylamino and mesitylamino groups do not dimerize but undergo unique tautomerization.
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Affiliation(s)
- Masataka Umetani
- Department of Chemistry , Graduate School of Science , Kyoto University , Japan
| | - Takayuki Tanaka
- Department of Chemistry , Graduate School of Science , Kyoto University , Japan
| | - Atsuhiro Osuka
- Department of Chemistry , Graduate School of Science , Kyoto University , Japan
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23
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Wang JF, Yao Y, Ning Y, Meng YS, Hou CL, Zhang J, Zhang JL. The design of rigid cyclic tripyrrins: the importance of intermolecular interactions on aggregation and luminescence. Org Chem Front 2018. [DOI: 10.1039/c8qo00313k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cyclic tripyrrin “locked” by a bridging benzyl moiety: enhancing the molecular rigidity and tuning aggregation and fluorescence via intermolecular halogen interactions.
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Affiliation(s)
- Jun-Fei Wang
- College of Materials Science and Optoelectronics Technology
- University of Chinese Academy of Sciences
- Beijing 100049
- P. R. China
| | - Yuhang Yao
- Beijing National Laboratory for Molecular Sciences
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing 100871
| | - Yingying Ning
- Beijing National Laboratory for Molecular Sciences
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing 100871
| | - Yin-Shan Meng
- Beijing National Laboratory for Molecular Sciences
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing 100871
| | - Chun-Liang Hou
- College of Materials Science and Optoelectronics Technology
- University of Chinese Academy of Sciences
- Beijing 100049
- P. R. China
| | - Jing Zhang
- College of Materials Science and Optoelectronics Technology
- University of Chinese Academy of Sciences
- Beijing 100049
- P. R. China
| | - Jun-Long Zhang
- Beijing National Laboratory for Molecular Sciences
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing 100871
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24
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Viqueira J, Durán ML, García-Vázquez JA, Castro J, Platas-Iglesias C, Esteban-Gómez D, Alzuet-Piña G, Moldes A, Nascimento OR. Modulating the DNA cleavage ability of copper(ii) Schiff bases through ternary complex formation. NEW J CHEM 2018. [DOI: 10.1039/c8nj03292k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Copper(ii) Schiff-bases were electrochemically synthesized and characterized. The presence of co-ligands such as 2,2′-bpy or phen in the metal coordination environment increases the DNA cleavage efficiency.
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Affiliation(s)
- Joaquín Viqueira
- Departamento de Química Inorgánica
- Campus Vida
- Universidad de Santiago de Compostela
- 15782 Santiago de Compostela
- Spain
| | - María L. Durán
- Departamento de Química Inorgánica
- Campus Vida
- Universidad de Santiago de Compostela
- 15782 Santiago de Compostela
- Spain
| | - José A. García-Vázquez
- Departamento de Química Inorgánica
- Campus Vida
- Universidad de Santiago de Compostela
- 15782 Santiago de Compostela
- Spain
| | - Jesús Castro
- Departamento de Química Inorgánica
- Facultade de Química
- Edificio de Ciencias Experimentais
- Universidade de Vigo
- 36310 Vigo
| | - Carlos Platas-Iglesias
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química
- Universidade da Coruña
- Campus da Zapateira
- 15008 A Coruña
- Spain
| | - David Esteban-Gómez
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química
- Universidade da Coruña
- Campus da Zapateira
- 15008 A Coruña
- Spain
| | - Gloria Alzuet-Piña
- Departament de Química Inorgànica
- Facultat de Farmàcia
- Universitat de València
- 46100 Burjassot
- Spain
| | - Angeles Moldes
- Departament de Química Inorgànica
- Facultat de Farmàcia
- Universitat de València
- 46100 Burjassot
- Spain
| | - Otaciro R. Nascimento
- Instituto de Física de Sao Carlos
- Universidade de Sao Paulo
- 13560-250 Sao Carlos
- Brazil
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Gautam R, Astashkin AV, Chang TM, Shearer J, Tomat E. Interactions of Metal-Based and Ligand-Based Electronic Spins in Neutral Tripyrrindione π Dimers. Inorg Chem 2017; 56:6755-6762. [PMID: 28497967 DOI: 10.1021/acs.inorgchem.7b01030] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ability of tetrapyrrolic macrocycles to stabilize unpaired electrons and engage in π-π interactions is essential for many electron-transfer processes in biology and materials engineering. Herein, we demonstrate that the formation of π dimers is recapitulated in complexes of a linear tripyrrolic analogue of naturally occurring pigments derived from heme decomposition. Hexaethyltripyrrindione (H3TD1) coordinates divalent transition metals (i.e., Pd, Cu, Ni) as a stable dianionic radical and was recently described as a robust redox-active ligand. The resulting planar complexes, which feature a delocalized ligand-based electronic spin, are stable at room temperature in air and support ligand-based one-electron processes. We detail the dimerization of neutral tripyrrindione complexes in solution through electron paramagnetic resonance (EPR) and visible absorption spectroscopic methods. Variable-temperature measurements using both EPR and absorption techniques allowed determination of the thermodynamic parameters of π dimerization, which resemble those previously reported for porphyrin radical cations. The inferred electronic structure, featuring coupling of ligand-based electronic spins in the π dimers, is supported by density functional theory (DFT) calculations.
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Affiliation(s)
- Ritika Gautam
- Department of Chemistry and Biochemistry, The University of Arizona , Tucson, Arizona 85721, United States
| | - Andrei V Astashkin
- Department of Chemistry and Biochemistry, The University of Arizona , Tucson, Arizona 85721, United States
| | - Tsuhen M Chang
- Department of Chemistry and Biochemistry, The University of Arizona , Tucson, Arizona 85721, United States
| | - Jason Shearer
- Department of Chemistry, University of Nevada , Reno, Nevada 89577, United States
| | - Elisa Tomat
- Department of Chemistry and Biochemistry, The University of Arizona , Tucson, Arizona 85721, United States
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26
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Peters GM, Winegrad JB, Gau MR, Imler GH, Xu B, Ren S, Wayland BB, Zdilla MJ. Synthesis and Structure of 2,5-Bis[N-(2,6-mesityl)iminomethyl]pyrrolylcobalt(II): Evidence for One-Electron-Oxidized, Redox Noninnocent Ligand Behavior. Inorg Chem 2017; 56:3377-3385. [DOI: 10.1021/acs.inorgchem.6b02898] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Garvin M. Peters
- Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States
| | - Jacob B. Winegrad
- Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States
| | - Michael R. Gau
- Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States
| | - Gregory H. Imler
- Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States
| | - Beibei Xu
- Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States
| | - Shenqiang Ren
- Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States
| | - Bradford B. Wayland
- Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States
| | - Michael J. Zdilla
- Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, United States
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