51
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Sugimoto H, Yano M, Sato K, Miyanishi M, Sugisaki K, Shiota Y, Kaga A, Yoshizawa K, Itoh S. Tin(II)-Nitrene Radical Complexes Formed by Electron Transfer from Redox-Active Ligand to Organic Azides and Their Reactivity in C(sp 3)-H Activation. Inorg Chem 2021; 60:18603-18607. [PMID: 34779619 DOI: 10.1021/acs.inorgchem.1c02806] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A tin(II) complex coordinated by a sterically demanding o-phenylenediamido ligand is synthesized. The ligand is redox-active to reach a tin(II) complex with the diiminobenzosemiquinone radial anion in the oxidation by AgPF6. The tin(II) complex reacts with a series of nosylazides (x-NO2C6H4-SO2-N3; x = o, m, or p) at -30 °C to yield the corresponding nitrene radical bound tin(II) complexes. The nitrene radical complexes exhibit C(sp3)-H activation and amination reactivity.
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Affiliation(s)
- Hideki Sugimoto
- Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Mayuka Yano
- Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kazunobu Sato
- Department of Chemistry, Graduate School of Science Osaka City University, 3-3-138 Sumiyoshi, Osaka, Osaka 558-8585, Japan
| | - Mayuko Miyanishi
- Institute for Materials Chemistry and Engineering and International Research Center for Molecular System, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kenji Sugisaki
- Department of Chemistry, Graduate School of Science Osaka City University, 3-3-138 Sumiyoshi, Osaka, Osaka 558-8585, Japan
| | - Yoshihito Shiota
- Institute for Materials Chemistry and Engineering and International Research Center for Molecular System, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Akira Kaga
- Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kazunari Yoshizawa
- Institute for Materials Chemistry and Engineering and International Research Center for Molecular System, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Shinobu Itoh
- Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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52
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Werr M, Kaifer E, Enders M, Asyuda A, Zharnikov M, Himmel H. Synthese eines Kupfer(I)‐Komplexes mit zwei ungepaarten Elektronen durch Oxidation eines Kupfer(II)‐Komplexes mit zwei redoxaktiven Liganden. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202109367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Marco Werr
- Anorganisch-Chemisches Institut Ruprecht-Karls Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
| | - Elisabeth Kaifer
- Anorganisch-Chemisches Institut Ruprecht-Karls Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
| | - Markus Enders
- Anorganisch-Chemisches Institut Ruprecht-Karls Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
| | - Andika Asyuda
- Angewandte Physikalische Chemie Ruprecht-Karls Universität Heidelberg Im Neuenheimer Feld 253 69120 Heidelberg Deutschland
| | - Michael Zharnikov
- Angewandte Physikalische Chemie Ruprecht-Karls Universität Heidelberg Im Neuenheimer Feld 253 69120 Heidelberg Deutschland
| | - Hans‐Jörg Himmel
- Anorganisch-Chemisches Institut Ruprecht-Karls Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
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53
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Werr M, Kaifer E, Enders M, Asyuda A, Zharnikov M, Himmel H. A Copper(I) Complex with Two Unpaired Electrons, Synthesised by Oxidation of a Copper(II) Complex with Two Redox-Active Ligands. Angew Chem Int Ed Engl 2021; 60:23451-23462. [PMID: 34423532 PMCID: PMC8596453 DOI: 10.1002/anie.202109367] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 07/30/2021] [Indexed: 01/10/2023]
Abstract
Two homoleptic copper(II) complexes [Cu(L1)2 ] and [Cu(L2)2 ] with anionic redox-active ligands were synthesised, one with urea azine (L1) and the other with thio-urea azine (L2) ligands. One-electron oxidation of the complexes initiates an unprecedented redox-induced electron transfer process, leading to monocationic copper(I) complexes [Cu(L1)2 ]+ and [Cu(L2)2 ]+ with two oxidised ligands. While [Cu(L1)2 ]+ is best described as a CuI complex with two neutral radical ligands that couple antiferromagnetically, [Cu(L2)2 ]+ is a CuI complex with two clearly different ligand units in the solid state and with a magnetic susceptibility close to a diamagnetic compound. Further one-electron oxidation of the complex with L1 ligands results in a dication [Cu(L1)2 ]2+ , best described as a CuI complex with a twofold oxidised, monocationic ligand and a neutral radical ligand. The stability in at least three redox states, the accumulation of spin density at the ligands and the facile ligand-metal electron transfer make these complexes highly attractive for a variety of applications; here the catalytic aerobic oxidation of alcohols to aldehydes is tested.
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Affiliation(s)
- Marco Werr
- Anorganisch-Chemisches InstitutRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Elisabeth Kaifer
- Anorganisch-Chemisches InstitutRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Markus Enders
- Anorganisch-Chemisches InstitutRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Andika Asyuda
- Angewandte Physikalische ChemieRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 25369120HeidelbergGermany
| | - Michael Zharnikov
- Angewandte Physikalische ChemieRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 25369120HeidelbergGermany
| | - Hans‐Jörg Himmel
- Anorganisch-Chemisches InstitutRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
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54
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Hanft A, Rottschäfer D, Wieprecht N, Geist F, Radacki K, Lichtenberg C. Aminotroponiminates: Impact of the NO 2 Functional Group on Coordination, Isomerisation, and Backbone Substitution. Chemistry 2021; 27:14250-14262. [PMID: 34314083 PMCID: PMC8597084 DOI: 10.1002/chem.202102324] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Indexed: 01/17/2023]
Abstract
Aminotroponiminate (ATI) ligands are a versatile class of redox-active and potentially cooperative ligands with a rich coordination chemistry that have consequently found a wide range of applications in synthesis and catalysis. While backbone substitution of these ligands has been investigated in some detail, the impact of electron-withdrawing groups on the coordination chemistry and reactivity of ATIs has been little investigated. We report here Li, Na, and K salts of an ATI ligand with a nitro-substituent in the backbone. It is demonstrated that the NO2 group actively contributes to the coordination chemistry of these complexes, effectively competing with the N,N-binding pocket as a coordination site. This results in an unprecedented E/Z isomerisation of an ATI imino group and culminates in the isolation of the first "naked" (i. e., without directional bonding to a metal atom) ATI anion. Reactions of sodium ATIs with silver(I) and tritylium salts gave the first N,N-coordinated silver ATI complexes and unprecedented backbone substitution reactions. Analytical techniques applied in this work include multinuclear (VT-)NMR spectroscopy, single-crystal X-ray diffraction analysis, and DFT calculations.
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Affiliation(s)
- Anna Hanft
- Institut für Anorganische Chemie, Fakultät für Chemie und Pharmazie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Dennis Rottschäfer
- Institut für Anorganische Chemie, Fakultät für Chemie und Pharmazie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Nele Wieprecht
- Institut für Anorganische Chemie, Fakultät für Chemie und Pharmazie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Felix Geist
- Institut für Anorganische Chemie, Fakultät für Chemie und Pharmazie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Krzysztof Radacki
- Institut für Anorganische Chemie, Fakultät für Chemie und Pharmazie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Crispin Lichtenberg
- Institut für Anorganische Chemie, Fakultät für Chemie und Pharmazie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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55
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Zuckerman LA, Vargo NP, May CV, Crockett MP, Hyre AS, McNeely J, Elinburg JK, Brown AM, Robinson JR, Rheingold AL, Doerrer LH. Thiolate-Thione Redox-Active Ligand with a Six-Membered Chelate Ring via Template Condensation and Its Pt(II) Complexes. Inorg Chem 2021; 60:13376-13387. [PMID: 34382778 DOI: 10.1021/acs.inorgchem.1c01693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A new template condensation reaction has been discovered in a mixture of Pt(II), thiobenzamide, and base. Four complexes of the general form [Pt(ctaPhR)2], R = CH3 (1a), H (1b), F (1c), Cl (1d), cta = condensed thioamide, have been prepared under similar conditions and thoroughly characterized by 1H NMR and UV-vis-NIR spectroscopy, (spectro)electrochemistry, elemental analysis, and single-crystal X-ray diffraction. The ligand is redox active and can be reduced from the initial monoanion to a dianionic and then trianionic state. Chemical reduction of 1a with [Cp2Co] yielded [Cp2Co]2[Pt(ctaPhCH3)2], [Cp2Co]2[1a], which has been similarly characterized with the addition of EPR spectroscopy and SQUID magnetization. The singly reduced form containing [1a]1-, (nBu4N)[Pt(ctaPhCH3)2], has been generated in situ and characterized by UV-vis and EPR spectroscopies. DFT studies of 1b, [1b]1-, and [1b]2- confirm the location of additional electrons in exclusively ligand-based orbitals. A detailed analysis of this redox-active ligand, with emphasis on the characteristics that favor noninnocent behavior in six-membered chelate rings, is included.
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Affiliation(s)
- Linda A Zuckerman
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Natasha P Vargo
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Claire V May
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Michael P Crockett
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Ariel S Hyre
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - James McNeely
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Jessica K Elinburg
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Alexander M Brown
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Jerome R Robinson
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Arnold L Rheingold
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0332, La Jolla, California 92093, United States
| | - Linda H Doerrer
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
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56
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van Leest N, de Zwart FJ, Zhou M, de Bruin B. Controlling Radical-Type Single-Electron Elementary Steps in Catalysis with Redox-Active Ligands and Substrates. JACS AU 2021; 1:1101-1115. [PMID: 34467352 PMCID: PMC8385710 DOI: 10.1021/jacsau.1c00224] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Indexed: 06/13/2023]
Abstract
Advances in (spectroscopic) characterization of the unusual electronic structures of open-shell cobalt complexes bearing redox-active ligands, combined with detailed mapping of their reactivity, have uncovered several new catalytic radical-type protocols that make efficient use of the synergistic properties of redox-active ligands, redox-active substrates, and the metal to which they coordinate. In this perspective, we discuss the tools available to study, induce, and control catalytic radical-type reactions with redox-active ligands and/or substrates, contemplating recent developments in the field, including some noteworthy tools, methods, and reactions developed in our own group. The main topics covered are (i) tools to characterize redox-active ligands; (ii) novel synthetic applications of catalytic reactions that make use of redox-active carbene and nitrene substrates at open-shell cobalt-porphyrins; (iii) development of catalytic reactions that take advantage of purely ligand- and substrate-based redox processes, coupled to cobalt-centered spin-changing events in a synergistic manner; and (iv) utilization of redox-active ligands to influence the spin state of the metal. Redox-active ligands have emerged as useful tools to generate and control reactive metal-coordinated radicals, which give access to new synthetic methodologies and intricate (electronic) structures, some of which are yet to be exposed.
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Affiliation(s)
- Nicolaas
P. van Leest
- Homogeneous, Supramolecular and Bio-Inspired
Catalysis Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Felix J. de Zwart
- Homogeneous, Supramolecular and Bio-Inspired
Catalysis Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Minghui Zhou
- Homogeneous, Supramolecular and Bio-Inspired
Catalysis Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous, Supramolecular and Bio-Inspired
Catalysis Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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57
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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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58
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Steuer L, Kaifer E, Himmel HJ. On the metal-ligand bonding in dinuclear complexes with redox-active guanidine ligands. Dalton Trans 2021; 50:9467-9482. [PMID: 34136887 DOI: 10.1039/d1dt01354h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Coordination compounds with redox-active ligands are currently intensively studied. Within this research theme, redox-active guanidines have been established as a new, eminent class of redox-active ligands. In this work the variation of metal-guanidine bonding in dinuclear transition metal complexes with bridging redox-active tetrakisguanidine ligands is analysed. A series of dinuclear complexes with different metals (Mn, Fe, Co, Ni, Cu and Zn) is synthesized, using either newly prepared redox-active tetrakisguanidino-dioxine or previously reported tetrakisguanidino-benzene ligands. The discussion of the bond properties in this work is predominantly based on the trends of structural parameters, derived from determination of single-crystal structures by X-ray diffraction and quantum chemical calculations. In addition, the trends in the redox potentials and magnetometric (SQUID) measurements on some of the complexes are included. Due to their combined σ- and π-electron donor capability, redox-active guanidine ligands are weak-field ligands; the σ- and π-bonding contributions vary with the metal. The results highlight the peculiarity of copper-guanidine bonding with a high π-bond contribution to metal-guanidine bonding, enabled by structural distortion of the coordination mode from tetrahedral in the direction of square-planar, short copper-guanidine bonds and minor displacement of the copper atoms from the ligand aromatic plane.
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Affiliation(s)
- Lena Steuer
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
| | - Elisabeth Kaifer
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
| | - Hans-Jörg Himmel
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
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59
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Lohmeyer L, Kaifer E, Enders M, Himmel H. Switching from Metal- to Ligand-Based Oxidation in Cobalt Complexes with Redox-Active Bisguanidine Ligands. Chemistry 2021; 27:11852-11867. [PMID: 34101917 PMCID: PMC8457109 DOI: 10.1002/chem.202101364] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Indexed: 11/19/2022]
Abstract
The control of the redox reactivity, magnetic and optical properties of the different redox states of complexes with redox‐active ligands permits their rational use in catalysis and materials science. The redox‐chemistry of octahedrally coordinated high‐spin CoII complexes (three unpaired electrons) with one redox‐active bisguanidine ligand and two acetylacetonato (acac) co‐ligands is completely changed by replacing the acac by hexafluoro‐acetylacetonato (hfacac) co‐ligands. The first one‐electron oxidation is metal‐centered in the case of the complexes with acac co‐ligands, giving diamagnetic CoIII complexes. By contrast, in the case of the less Lewis‐basic hfacac co‐ligands, the first one‐electron oxidation becomes ligand‐centered, leading to high‐spin CoII complexes with a radical monocationic guanidine ligand unit (four unpaired electrons). Ferromagnetic coupling between the spins on the metal and the organic radical in solution is evidenced by temperature‐dependent paramagnetic NMR studies, allowing to estimate the isotropic exchange coupling constant in solution. Second one‐electron oxidation leads to high‐spin CoII complexes with dicationic guanidine ligand units (three unpaired electrons) in the presence of hfacac co‐ligands, but to low‐spin CoIII complexes with radical monocationic, peralkylated guanidine ligand (one unpaired electron) in the presence of acac co‐ligands. The analysis of the electronic structures is complemented by quantum‐chemical calculations on the spin density distributions and relative energies of the possible redox isomers.
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Affiliation(s)
- Lukas Lohmeyer
- Inorganic ChemistryRuprecht-Karls University of HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Elisabeth Kaifer
- Inorganic ChemistryRuprecht-Karls University of HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Markus Enders
- Inorganic ChemistryRuprecht-Karls University of HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Hans‐Jörg Himmel
- Inorganic ChemistryRuprecht-Karls University of HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
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60
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Zhang Z, Stückrath JB, Grimme S, Gansäuer A. Titanocene‐Catalyzed [2+2] Cycloaddition of Bisenones and Comparison with Photoredox Catalysis and Established Methods. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Zhenhua Zhang
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard-Domagk-Strasse 1 53121 Bonn Germany
| | - Julius B. Stückrath
- Mulliken Center for Theoretical Chemistry Institut für Physikalische und Theoretische Chemie Universität Bonn Beringstrasse 4 53115 Bonn Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry Institut für Physikalische und Theoretische Chemie Universität Bonn Beringstrasse 4 53115 Bonn Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard-Domagk-Strasse 1 53121 Bonn Germany
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61
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Zhang Z, Stückrath JB, Grimme S, Gansäuer A. Titanocene-Catalyzed [2+2] Cycloaddition of Bisenones and Comparison with Photoredox Catalysis and Established Methods. Angew Chem Int Ed Engl 2021; 60:14339-14344. [PMID: 33871126 PMCID: PMC8251790 DOI: 10.1002/anie.202102739] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Indexed: 12/17/2022]
Abstract
Cp2 Ti(TFA) is a broadly applicable catalyst for the [2+2] cycloaddition of bisenones by inner-sphere electron transfer. The attractiveness of this mechanism is shown by comparison with outer-sphere ET methods. DFT calculations show that the reaction proceeds through a unique unfavorable 5-exo (the rate-determining step) and a favorable 4-exo cyclization.
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Affiliation(s)
- Zhenhua Zhang
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Strasse 153121BonnGermany
| | - Julius B. Stückrath
- Mulliken Center for Theoretical ChemistryInstitut für Physikalische und Theoretische ChemieUniversität BonnBeringstrasse 453115BonnGermany
| | - Stefan Grimme
- Mulliken Center for Theoretical ChemistryInstitut für Physikalische und Theoretische ChemieUniversität BonnBeringstrasse 453115BonnGermany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Strasse 153121BonnGermany
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62
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Shangin PG, Krylova IV, Lalov AV, Kozmenkova AY, Saverina EA, Buikin PA, Korlyukov AA, Starikova AA, Nikolaevskaya EN, Egorov MP, Syroeshkin MA. Supramolecular D⋯A-layered structures based on germanium complexes with 2,3-dihydroxynaphthalene and N, N'-bidentate ligands. RSC Adv 2021; 11:21527-21536. [PMID: 35478811 PMCID: PMC9034134 DOI: 10.1039/d1ra02691g] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/12/2021] [Indexed: 11/25/2022] Open
Abstract
The concept of using redox-active ligands, which has become extremely widespread in organometallic chemistry, is often considered from 'their effect on the metal center properties' point of view and 'how to modify the ligands'. In this paper, we present the reverse side of this effective approach - a dramatic change of redox properties of ligands under the influence of a redox-inert metal. Germanium derivatives based on 2,3-dihydroxynaphthalene (1) and N,N'-bidentate ligands, namely 2,2'-bipyridine (2) and 1,10-phenanthroline (3), were obtained and characterized by CV, UV-vis spectroscopy, DFT calculations and in the case of 3 X-ray diffraction. It was shown that the HOMO of the complexes is almost completely located on the naphthalene fragment while the LUMO is on the N,N-ligands. At the same time, there are no boundary molecular orbitals on the germanium atom, but it forms the axial part of the molecule holding two opposite motifs together. Moreover, it sharply affects the level of HOMO and LUMO. Derivatives 2 and 3 are more easily oxidized compared to 2,3-dihydroxynaphthalene by 0.31-0.34 V (7-8 kcal mol-1) and are more easily reduced compared to N,N-donors by 1.08-1.15 V (25-26.5 kcal mol-1). All this together makes it possible to form a system with a narrow HOMO/LUMO gap (∼2 eV). The crystal structure of 3 consists of alternating monomolecular easily oxidizing and easily reducing layers formed due to intermolecular interactions, in particular π-stacking. In addition, in contrast to 1 that starts to decompose noticeably at the temperatures from 200 °C, 2 and 3 have an extremely high thermal stability. They remain stable with no signs of decomposition and melting up to 400 °С. We believe that this approach to the formation of the supramolecular structure may present prospects for obtaining new functional materials.
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Affiliation(s)
- Pavel G Shangin
- N. D. Zelinsky Institute of Organic Chemistry 119991 Moscow Russia
| | - Irina V Krylova
- N. D. Zelinsky Institute of Organic Chemistry 119991 Moscow Russia
| | - Andrey V Lalov
- N. D. Zelinsky Institute of Organic Chemistry 119991 Moscow Russia
| | | | | | - Petr A Buikin
- A. N. Nesmeyanov Institute of Organoelement Compounds 119991 Moscow Russia
| | | | - Alyona A Starikova
- Institute of Physical and Organic Chemistry, Southern Federal University 344090 Rostov-on-Don Russia
| | | | - Mikhail P Egorov
- N. D. Zelinsky Institute of Organic Chemistry 119991 Moscow Russia
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63
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Das S, Mondal R, Chakraborty G, Guin AK, Das A, Paul ND. Zinc Stabilized Azo-anion Radical in Dehydrogenative Synthesis of N-Heterocycles. An Exclusively Ligand Centered Redox Controlled Approach. ACS Catal 2021. [DOI: 10.1021/acscatal.1c00275] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Siuli Das
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India
| | - Rakesh Mondal
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India
| | - Gargi Chakraborty
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India
| | - Amit Kumar Guin
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India
| | - Abhishek Das
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Nanda D. Paul
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India
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64
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Petrov PA, Filippova EA, Eltsov IV, Sukhikh TS, Piskunov AV, Sokolov MN. Catecholate derivatives of zirconocene: facile methylation of a catecholate ring. J Organomet Chem 2021. [DOI: 10.1016/j.jorganchem.2021.121946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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65
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Liang Q, DeMuth JC, Radović A, Wolford NJ, Neidig ML, Song D. [2Fe-2S] Cluster Supported by Redox-Active o-Phenylenediamide Ligands and Its Application toward Dinitrogen Reduction. Inorg Chem 2021; 60:13811-13820. [PMID: 34043353 DOI: 10.1021/acs.inorgchem.1c00683] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
As prevalent cofactors in living organisms, iron-sulfur clusters participate in not only the electron-transfer processes but also the biosynthesis of other cofactors. Many synthetic iron-sulfur clusters have been used in model studies, aiming to mimic their biological functions and to gain mechanistic insight into the related biological systems. The smallest [2Fe-2S] clusters are typically used for one-electron processes because of their limited capacity. Our group is interested in functionalizing small iron-sulfur clusters with redox-active ligands to enhance their electron storage capacity, because such functionalized clusters can potentially mediate multielectron chemical transformations. Herein we report the synthesis, structural characterization, and catalytic activity of a diferric [2Fe-2S] cluster functionalized with two o-phenylenediamide ligands. The electrochemical and chemical reductions of such a cluster revealed rich redox chemistry. The functionalized diferric cluster can store up to four electrons reversibly, where the first two reduction events are ligand-based and the remainder metal-based. The diferric [2Fe-2S] cluster displays catalytic activity toward silylation of dinitrogen, affording up to 88 equiv of the amine product per iron center.
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Affiliation(s)
- Qiuming Liang
- Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Joshua C DeMuth
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Aleksa Radović
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Nikki J Wolford
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Michael L Neidig
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Datong Song
- Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
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66
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Lavrent’ev VA, Shinkar’ EV, Smolyaninov IV, Ryabukhin YI, Berberova NT. Antimony(V) and Tin(IV) Complexes with Redox-Active O,N,O-Donor Ligand in the Electrosynthesis of Symmetrical Disulfides. RUSS J COORD CHEM+ 2021. [DOI: 10.1134/s1070328421050031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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67
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Thompson BL, Heiden ZM. Tuning the reduction potentials of benzoquinone through the coordination to Lewis acids. Phys Chem Chem Phys 2021; 23:9822-9831. [PMID: 33908513 DOI: 10.1039/d1cp01266e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Electron transfer promoted by the coordination of a substrate molecule to a Lewis acid or hydrogen bonding group is a critical step in many biological and catalytic transformations. This computational study investigates the nature of the interaction between benzoquinone and one and two Lewis acids by examining the influence of Lewis acid strength on the ability to alter the two reduction potentials of the coordinated benzoquinone molecule. To investigate this interaction, the coordination of the neutral (Q), singly reduced ([Q]˙-), and doubly reduced benzoquinone ([Q]2-) molecule to eight Lewis acids was analyzed. Coordination of benzoquinone to a Lewis acid became more favorable by 25 kcal mol-1 with each reduction of the benzoquinone fragment. Coordination of benzoquinone to a Lewis acid also shifted each of the reduction potentials of the coordinated benzoquinone anodically by 0.50 to 1.5 V, depending on the strength of the Lewis acid, with stronger Lewis acids exhibiting a larger effect on the reduction potential. Coordination of a second Lewis acid further altered each of the reduction potentials by an additional 0.70 to 1.6 V. Replacing one of the Lewis acids with a proton resulted in the ability to modify the pKa of the protonated Lewis acid-Q/[Q]˙-/[Q]2- adducts by about 10 pKa units, in addition to being able to alter the ability to transfer a hydrogen atom by 10 kcal mol-1, and the capacity to transfer a hydride by about 30 kcal mol-1.
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Affiliation(s)
- Brena L Thompson
- Department of Chemistry, Washington State University, Pullman, Washington 99164, USA.
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68
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Leconte N, Berthiol F, Philouze C, Thomas F. Copper Complexes of the Tetradentate
N,N′
‐Bis(2‐amino‐3,5‐di‐
tert
‐butylphenyl)‐2,2′‐diaminobiphenyl Ligand. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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69
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Smolyaninov IV, Fukin GK, Berberova NT, Poddel’sky AI. Triphenylantimony(V) Catecholates of the Type (3-RS-4,6-DBCat)SbPh 3-Catechol Thioether Derivatives: Structure, Electrochemical Properties, and Antiradical Activity. Molecules 2021; 26:2171. [PMID: 33918799 PMCID: PMC8069174 DOI: 10.3390/molecules26082171] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 11/16/2022] Open
Abstract
A new series of triphenylantimony(V) 3-alkylthio/arylthio-substituted 4,6-di-tert-butylcatecholates of the type (3-RS-4,6-DBCat)SbPh3, where R = n-butyl (1), n-hexyl (2), n-octyl (3), cyclopentyl (4), cyclohexyl (5), benzyl (6), phenyl (7), and naphthyl-2 (8), were synthesized from the corresponding catechol thioethers and Ph3SbBr2 in the presence of a base. The crystal structures of 1, 2, 3, and 5 were determined by single-crystal X-ray analysis. The coordination polyhedron of 1-3 is better described as a tetragonal pyramid with a different degree of distortion, while that for 5- was a distorted trigonal bipyramid (τ = 0.014, 0.177, 0.26, 0.56, respectively). Complexes demonstrated different crystal packing of molecules. The electrochemical oxidation of the complexes involved the catecholate group as well as the thioether linker. The introduction of a thioether fragment into the aromatic ring of catechol ligand led to a shift in the potential of the "catechol/o-semiquinone" redox transition to the anodic region, which indicated the electron-withdrawing nature of the RS group. The radical scavenging activity of the complexes was determined in the reaction with DPPH radical.
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Affiliation(s)
- Ivan V. Smolyaninov
- Department of Chemistry, Astrakhan State Technical University, 16 Tatisheva Str., 414056 Astrakhan, Russia; (I.V.S.); (N.T.B.)
| | - Georgy K. Fukin
- G.A. Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences, 49 Tropinina Str., 603137 Nizhny Novgorod, Russia;
| | - Nadezhda T. Berberova
- Department of Chemistry, Astrakhan State Technical University, 16 Tatisheva Str., 414056 Astrakhan, Russia; (I.V.S.); (N.T.B.)
| | - Andrey I. Poddel’sky
- G.A. Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences, 49 Tropinina Str., 603137 Nizhny Novgorod, Russia;
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70
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Hanft A, Radacki K, Lichtenberg C. Cationic Bismuth Aminotroponiminates: Charge Controls Redox Properties. Chemistry 2021; 27:6230-6239. [PMID: 33326650 PMCID: PMC8048980 DOI: 10.1002/chem.202005186] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Indexed: 01/03/2023]
Abstract
The behavior of the redox‐active aminotroponiminate (ATI) ligand in the coordination sphere of bismuth has been investigated in neutral and cationic compounds, [Bi(ATI)3] and [Bi(ATI)2Ln][A] (L=neutral ligand; n=0, 1; A=counteranion). Their coordination chemistry in solution and in the solid state has been analyzed through (variable‐temperature) NMR spectroscopy, line‐shape analysis, and single‐crystal X‐ray diffraction analyses, and their Lewis acidity has been evaluated by using the Gutmann–Beckett method (and modifications thereof). Cyclic voltammetry, in combination with DFT calculations, indicates that switching between ligand‐ and metal‐centered redox events is possible by altering the charge of the compounds from 0 in neutral species to +1 in cationic compounds. This adds important facets to the rich redox chemistry of ATIs and to the redox chemistry of bismuth compounds, which is, so far, largely unexplored.
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Affiliation(s)
- Anna Hanft
- Department of Inorganic Chemistry, Julius-Maximilians-University Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Krzysztof Radacki
- Department of Inorganic Chemistry, Julius-Maximilians-University Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Crispin Lichtenberg
- Department of Inorganic Chemistry, Julius-Maximilians-University Würzburg, Am Hubland, 97074, Würzburg, Germany
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71
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Huang L, Bismuto A, Rath SA, Trapp N, Morandi B. Ruthenium-Catalyzed Dehydrogenation Through an Intermolecular Hydrogen Atom Transfer Mechanism. Angew Chem Int Ed Engl 2021; 60:7290-7296. [PMID: 33403774 PMCID: PMC8048662 DOI: 10.1002/anie.202015837] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Indexed: 12/17/2022]
Abstract
The direct dehydrogenation of alkanes is among the most efficient ways to access valuable alkene products. Although several catalysts have been designed to promote this transformation, they have unfortunately found limited applications in fine chemical synthesis. Here, we report a conceptually novel strategy for the catalytic, intermolecular dehydrogenation of alkanes using a ruthenium catalyst. The combination of a redox-active ligand and a sterically hindered aryl radical intermediate has unleashed this novel strategy. Importantly, mechanistic investigations have been performed to provide a conceptual framework for the further development of this new catalytic dehydrogenation system.
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Affiliation(s)
- Lin Huang
- Max-Planck-Institut für KohlenforschungKaiser-Wihelm-Platz 145470Mülheim an der RuhrGermany
- Laboratorium für Organische Chemie ETH ZürichVladimir-Prelog-Weg 3, HCI8093ZürichSwitzerland
| | - Alessandro Bismuto
- Laboratorium für Organische Chemie ETH ZürichVladimir-Prelog-Weg 3, HCI8093ZürichSwitzerland
| | - Simon A. Rath
- Laboratorium für Organische Chemie ETH ZürichVladimir-Prelog-Weg 3, HCI8093ZürichSwitzerland
| | - Nils Trapp
- Laboratorium für Organische Chemie ETH ZürichVladimir-Prelog-Weg 3, HCI8093ZürichSwitzerland
| | - Bill Morandi
- Max-Planck-Institut für KohlenforschungKaiser-Wihelm-Platz 145470Mülheim an der RuhrGermany
- Laboratorium für Organische Chemie ETH ZürichVladimir-Prelog-Weg 3, HCI8093ZürichSwitzerland
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72
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Huang L, Bismuto A, Rath SA, Trapp N, Morandi B. Ruthenium‐Catalyzed Dehydrogenation Through an Intermolecular Hydrogen Atom Transfer Mechanism. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202015837] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Lin Huang
- Max-Planck-Institut für Kohlenforschung Kaiser-Wihelm-Platz 1 45470 Mülheim an der Ruhr Germany
- Laboratorium für Organische Chemie ETH Zürich Vladimir-Prelog-Weg 3, HCI 8093 Zürich Switzerland
| | - Alessandro Bismuto
- Laboratorium für Organische Chemie ETH Zürich Vladimir-Prelog-Weg 3, HCI 8093 Zürich Switzerland
| | - Simon A. Rath
- Laboratorium für Organische Chemie ETH Zürich Vladimir-Prelog-Weg 3, HCI 8093 Zürich Switzerland
| | - Nils Trapp
- Laboratorium für Organische Chemie ETH Zürich Vladimir-Prelog-Weg 3, HCI 8093 Zürich Switzerland
| | - Bill Morandi
- Max-Planck-Institut für Kohlenforschung Kaiser-Wihelm-Platz 1 45470 Mülheim an der Ruhr Germany
- Laboratorium für Organische Chemie ETH Zürich Vladimir-Prelog-Weg 3, HCI 8093 Zürich Switzerland
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73
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Lohmeyer L, Schön F, Kaifer E, Himmel H. Stimulierung eines redoxinduzierten Elektronentransfers durch Interligand‐Wasserstoffbrücken in einem Cobaltkomplex mit redoxaktivem Guanidin‐Liganden. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202101423] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Lukas Lohmeyer
- Anorganisch-Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
| | - Florian Schön
- Anorganisch-Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
| | - Elisabeth Kaifer
- Anorganisch-Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
| | - Hans‐Jörg Himmel
- Anorganisch-Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
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74
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Lohmeyer L, Schön F, Kaifer E, Himmel HJ. Stimulation of Redox-Induced Electron Transfer by Interligand Hydrogen Bonding in a Cobalt Complex with Redox-Active Guanidine Ligand. Angew Chem Int Ed Engl 2021; 60:10415-10422. [PMID: 33616266 PMCID: PMC8252010 DOI: 10.1002/anie.202101423] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Indexed: 12/27/2022]
Abstract
Octahedrally coordinated cobalt(II) complexes with a redox‐active bisguanidine ligand and acac co‐ligands were synthesized and their redox chemistry analysed in detail. The N−H functions in a bisguanidine ligand with partially alkylated guanidino groups form N−H⋅⋅⋅O hydrogen bonds with the acac co‐ligands, thereby massively influencing the redox chemistry. For all complexes, the first one‐electron oxidation is metal‐centred, leading to CoIII complexes with neutral bisguanidine ligand units. Further one‐electron oxidation is ligand‐centred in the case of Co–bisguanidine complexes with fully alkylated guanidino groups, giving CoIII complexes with radical monocationic bisguanidine ligands. On the other hand, the hydrogen‐bond strengthening upon oxidation of the Co–bisguanidine complex with partially alkylated guanidino groups initiates metal reduction (CoIII→CoII) and two‐electron oxidation of the guanidine ligand, providing the first example for the stimulation of redox‐induced electron transfer by interligand hydrogen bonding.
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Affiliation(s)
- Lukas Lohmeyer
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Florian Schön
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Elisabeth Kaifer
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Hans-Jörg Himmel
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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75
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Hilche T, Reinsberg PH, Klare S, Liedtke T, Schäfer L, Gansäuer A. Design Platform for Sustainable Catalysis with Radicals: Electrochemical Activation of Cp 2 TiCl 2 for Catalysis Unveiled. Chemistry 2021; 27:4903-4912. [PMID: 33085978 PMCID: PMC7986168 DOI: 10.1002/chem.202004519] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Indexed: 12/17/2022]
Abstract
The combination of synthesis, rotating ring-disk electrode (RRDE) and cyclic voltammetry (CV) measurements, and computational investigations with the aid of DFT methods shows how a thiourea, a squaramide, and a bissulfonamide as additives affect the Eq Cr equilibrium of Cp2 TiCl2 . We have, for the first time, provided quantitative data for the Eq Cr equilibrium and have determined the stoichiometry of adduct formation of [Cp2 Ti(III)Cl2 ]- , [Cp2 Ti(III)Cl] and [Cp2 Ti(IV)Cl2 ] and the additives. By studying the structures of the complexes formed by DFT methods, we have established the Gibbs energies and enthalpies of complex formation as well as the adduct structures. The results not only demonstrate the correctness of our use of the Eq Cr equilibrium as predictor for sustainable catalysis. They are also a design platform for the development of novel additives in particular for enantioselective catalysis.
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Affiliation(s)
- Tobias Hilche
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Straße 153121BonnGermany
| | - Philip H. Reinsberg
- Institut für Physikalische und Theoretische Chemie, Universität BonnRömerstraße 16453117BonnGermany
| | - Sven Klare
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Straße 153121BonnGermany
| | - Theresa Liedtke
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Straße 153121BonnGermany
| | - Luise Schäfer
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Straße 153121BonnGermany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Straße 153121BonnGermany
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76
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Funk P, Richrath RB, Bohle F, Grimme S, Gansäuer A. Oxidation Under Reductive Conditions: From Benzylic Ethers to Acetals with Perfect Atom-Economy by Titanocene(III) Catalysis. Angew Chem Int Ed Engl 2021; 60:5482-5488. [PMID: 33245820 PMCID: PMC7986230 DOI: 10.1002/anie.202013561] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Indexed: 12/19/2022]
Abstract
Described here is a titanocene-catalyzed reaction for the synthesis of acetals and hemiaminals from benzylic ethers and benzylic amines, respectively, with pendant epoxides. The reaction proceeds by catalysis in single-electron steps. The oxidative addition comprises an epoxide opening. An H-atom transfer, to generate a benzylic radical, serves as a radical translocation step, and an organometallic oxygen rebound as a reductive elimination. The reaction mechanism was studied by high-level dispersion corrected hybrid functional DFT with implicit solvation. The low-energy conformational space was searched by the efficient CREST program. The stereoselectivity was deduced from the lowest lying benzylic radical structures and their conformations are controlled by hyperconjugative interactions and steric interactions between the titanocene catalyst and the aryl groups of the substrate. An interesting mechanistic aspect is that the oxidation of the benzylic center occurs under reducing conditions.
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Affiliation(s)
- Pierre Funk
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Str. 153121BonnGermany
| | - Ruben B. Richrath
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Str. 153121BonnGermany
| | - Fabian Bohle
- Mulliken Center for Theoretical ChemistryInstitut für Physikalische und Theoretische ChemieUniversität BonnBeringstraße 453115BonnGermany
| | - Stefan Grimme
- Mulliken Center for Theoretical ChemistryInstitut für Physikalische und Theoretische ChemieUniversität BonnBeringstraße 453115BonnGermany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard Domagk-Str. 153121BonnGermany
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77
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Hay MA, Boskovic C. Lanthanoid Complexes as Molecular Materials: The Redox Approach. Chemistry 2021; 27:3608-3637. [PMID: 32965741 DOI: 10.1002/chem.202003761] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Indexed: 11/05/2022]
Abstract
The development of molecular materials with novel functionality offers promise for technological innovation. Switchable molecules that incorporate redox-active components are enticing candidate compounds due to their potential for electronic manipulation. Lanthanoid metals are most prevalent in their trivalent state and usually redox-activity in lanthanoid complexes is restricted to the ligand. The unique electronic and physical properties of lanthanoid ions have been exploited for various applications, including in magnetic and luminescent materials as well as in catalysis. Lanthanoid complexes are also promising for applications reliant on switchability, where the physical properties can be modulated by varying the oxidation state of a coordinated ligand. Lanthanoid-based redox activity is also possible, encompassing both divalent and tetravalent metal oxidation states. Thus, utilization of redox-active lanthanoid metals offers an attractive opportunity to further expand the capabilities of molecular materials. This review surveys both ligand and lanthanoid centered redox-activity in pre-existing molecular systems, including tuning of lanthanoid magnetic and photophysical properties by modulating the redox states of coordinated ligands. Ultimately the combination of redox-activity at both ligands and metal centers in the same molecule can afford novel electronic structures and physical properties, including multiconfigurational electronic states and valence tautomerism. Further targeted exploration of these features is clearly warranted, both to enhance understanding of the underlying fundamental chemistry, and for the generation of a potentially important new class of molecular material.
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Affiliation(s)
- Moya A Hay
- School of Chemistry, University of Melbourne, Victoria, 3010, Australia
| | - Colette Boskovic
- School of Chemistry, University of Melbourne, Victoria, 3010, Australia
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78
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Funk P, Richrath RB, Bohle F, Grimme S, Gansäuer A. Oxidation Under Reductive Conditions: From Benzylic Ethers to Acetals with Perfect Atom‐Economy by Titanocene(III) Catalysis. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202013561] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Pierre Funk
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Str. 1 53121 Bonn Germany
| | - Ruben B. Richrath
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Str. 1 53121 Bonn Germany
| | - Fabian Bohle
- Mulliken Center for Theoretical Chemistry Institut für Physikalische und Theoretische Chemie Universität Bonn Beringstraße 4 53115 Bonn Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry Institut für Physikalische und Theoretische Chemie Universität Bonn Beringstraße 4 53115 Bonn Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie Universität Bonn Gerhard Domagk-Str. 1 53121 Bonn Germany
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79
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Haaf S, Kaifer E, Wadepohl H, Himmel H. Use of Crown Ether Functions as Secondary Coordination Spheres for the Manipulation of Ligand-Metal Intramolecular Electron Transfer in Copper-Guanidine Complexes. Chemistry 2021; 27:959-970. [PMID: 32833269 PMCID: PMC7839521 DOI: 10.1002/chem.202003469] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Indexed: 01/16/2023]
Abstract
Intramolecular electron transfer (IET) between a redox-active organic ligand and a metal in a complex is of fundamental interest and used in a variety of applications. In this work it is demonstrated that secondary coordination sphere motifs can be applied to trigger a radical change in the electronic structure of copper complexes with a redox-active guanidine ligand through ligand-metal IET. Hence, crown ether functions attached to the ligand allow the manipulation of the degree of IET between the guanidine ligand and the copper atom through metal encapsulation.
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Affiliation(s)
- Sebastian Haaf
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Elisabeth Kaifer
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Hubert Wadepohl
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Hans‐Jörg Himmel
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
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80
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Ehret F, Filippou V, Blickle S, Bubrin M, Záliš S, Kaim W. Structural and Oxidation State Alternatives in Platinum and Palladium Complexes of a Redox-Active Amidinato Ligand. Chemistry 2021; 27:3374-3381. [PMID: 32959415 PMCID: PMC7986709 DOI: 10.1002/chem.202003636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Indexed: 11/07/2022]
Abstract
Reaction of [Pt(DMSO)2 Cl2 ] or [Pd(MeCN)2 Cl2 ] with the electron-rich LH=N,N'-bis(4-dimethylaminophenyl)ethanimidamide yielded mononuclear [PtL2 ] (1) but dinuclear [Pd2 L4 ] (2), a paddle-wheel complex. The neutral compounds were characterized through experiments (crystal structures, electrochemistry, UV-vis-NIR spectroscopy, magnetic resonance) and TD-DFT calculations as metal(II) species with noninnocent ligands L- . The reversibly accessible cations [PtL2 ]+ and [Pd2 L4 ]+ were also studied, the latter as [Pd2 L4 ][B{3,5-(CF3 )2 C6 H3 }4 ] single crystals. Experimental and computational investigations were directed at the elucidation of the electronic structures, establishing the correct oxidation states within the alternatives [PtII (L- )2 ] or [Pt. (L )2 ], [PtII (L0.5- )2 ]+ or [PtIII (L- )2 ]+ , [(PdII )2 (μ-L- )4 ] or [(Pd1.5 )2 (μ-L0.75- )4 ], and [(Pd2.5 )2 (μ-L- )4 ]+ or [(PdII )2 (μ-L0.75- )4 ]+ . In each case, the first alternative was shown to be most appropriate. Remarkable results include the preference of platinum for mononuclear planar [PtL2 ] with an N-Pt-N bite angle of 62.8(2)° in contrast to [Pd2 L4 ], and the dimetal (Pd2 4+ →Pd2 5+ ) instead of ligand (L- →L ) oxidation of the dinuclear palladium compound.
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Affiliation(s)
- Fabian Ehret
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70550, Stuttgart, Germany
| | - Vasileios Filippou
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70550, Stuttgart, Germany
| | - Svenja Blickle
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70550, Stuttgart, Germany
| | - Martina Bubrin
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70550, Stuttgart, Germany
| | - Stanislav Záliš
- J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, 18223, Prague, Czech Republic
| | - Wolfgang Kaim
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70550, Stuttgart, Germany
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81
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Chatterjee B, Chang W, Werlé C. Molecularly Controlled Catalysis – Targeting Synergies Between Local and Non‐local Environments. ChemCatChem 2020. [DOI: 10.1002/cctc.202001431] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Basujit Chatterjee
- Max Planck Institute for Chemical Energy Conversion Stiftstr. 34–36 45470 Mülheim an der Ruhr Germany
- Ruhr University Bochum Universitätsstr. 150 44801 Bochum Germany
| | - Wei‐Chieh Chang
- Max Planck Institute for Chemical Energy Conversion Stiftstr. 34–36 45470 Mülheim an der Ruhr Germany
- Ruhr University Bochum Universitätsstr. 150 44801 Bochum Germany
| | - Christophe Werlé
- Max Planck Institute for Chemical Energy Conversion Stiftstr. 34–36 45470 Mülheim an der Ruhr Germany
- Ruhr University Bochum Universitätsstr. 150 44801 Bochum Germany
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82
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Bains AK, Singh V, Adhikari D. Homogeneous Nickel-Catalyzed Sustainable Synthesis of Quinoline and Quinoxaline under Aerobic Conditions. J Org Chem 2020; 85:14971-14979. [PMID: 33174416 DOI: 10.1021/acs.joc.0c01819] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Dehydrogenative coupling-based reactions have emerged as an efficient route toward the synthesis of a plethora of heterocyclic rings. Herein, we report an efficacious, nickel-catalyzed synthesis of two important heterocycles such as quinoline and quinoxaline. The catalyst is molecularly defined, is phosphine-free, and can operate at a mild reaction temperature of 80 °C. Both the heterocycles can be easily assembled via double dehydrogenative coupling, starting from 2-aminobenzyl alcohol/1-phenylethanol and diamine/diol, respectively, in a shorter span of reaction time. This environmentally benign synthetic protocol employing an inexpensive catalyst can rival many other transition-metal systems that have been developed for the fabrication of two putative heterocycles. Mechanistically, the dehydrogenation of secondary alcohol follows clean pseudo-first-order kinetics and exhibits a sizable kinetic isotope effect. Intriguingly, this catalyst provides an example of storing the trapped hydrogen in the ligand backbone, avoiding metal-hydride formation. Easy regeneration of the oxidized form of the catalyst under aerobic/O2 oxidation makes this protocol eco-friendly and easy to handle.
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Affiliation(s)
- Amreen K Bains
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar, 140306 Mohali, India
| | - Vikramjeet Singh
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar, 140306 Mohali, India
| | - Debashis Adhikari
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, SAS Nagar, 140306 Mohali, India
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83
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Braun JD, Gray PA, Sidhu BK, Nemez DB, Herbert DE. Zn-Templated synthesis of substituted (2,6-diimine)pyridine proligands and evaluation of their iron complexes as anolytes for flow battery applications. Dalton Trans 2020; 49:16175-16183. [PMID: 32301445 DOI: 10.1039/d0dt00543f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Pseudo-octahedral iron complexes supported by tridentate N^N^N-binding, redox 'non-innocent' diiminepyridine (DIP) ligands exhibit multiple reversible ligand-based reductions that suggest the potential application of these complexes as anolytes in redox flow batteries (RFBs). When bearing aryl groups at the imine nitrogens, substitution at the 4-position can be used to tune these redox potentials and impact other properties relevant to RFB applications, such as solubility and stability over extended cycling. DIP ligands bearing electron-withdrawing groups (EWGs) in this position, however, can be challenging to isolate via typical condensation routes involving para-substituted anilines and 2,6-diacetylpyridine. In this work, we demonstrate a high-yielding Zn-templated synthesis of DIP ligands bearing strong EWGs. The synthesis and electrochemical characterization of iron(ii) complexes of these ligands is also described, along with properties relevant to their potential application as RFB anolytes.
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Affiliation(s)
- Jason D Braun
- Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada.
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84
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Chegerev MG, Arsenyeva KV, Cherkasov AV, Piskunov AV. Specific Features of EPR Spectroscopy of Organotin Compounds with Paramagnetic Ligands of the o-Iminobenzosemiquinone Type. RUSS J COORD CHEM+ 2020. [DOI: 10.1134/s1070328420110019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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85
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Petrov PA, Kadilenko EM, Sukhikh TS, Eltsov IV, Gushchin AL, Nadolinny VA, Sokolov MN, Gritsan NP. A Sterically Hindered Derivative of 2,1,3-Benzotelluradiazole: A Way to the First Structurally Characterised Monomeric Tellurium-Nitrogen Radical Anion. Chemistry 2020; 26:14688-14699. [PMID: 32776633 DOI: 10.1002/chem.202002799] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/22/2020] [Indexed: 12/14/2022]
Abstract
Interaction of the tetradentate redox-active 6,6'-[1,2-phenylenebis(azanediyl)]bis(2,4-di-tert-butylphenol) (H4 L) with TeCl4 leads to neutral diamagnetic compound TeL (1) in high yield. The molecule of 1 has a nearly planar TeN2 O2 fragment, which suggests the formulation of 1 as TeII L2- , in agreement with the results of DFT calculations and QTAIM and NBO analyses. Reduction of 1 with one equivalent of [CoCp2 ] leads to quantitative formation of the paramagnetic salt [CoCp2 ]+ [1].- , which was characterised by single-crystal XRD. The solution EPR spectrum of [CoCp2 ]+ [1].- at room temperature features a quintet due to splitting on two equivalent 14 N nuclei. Below 150 K it turns into a broad singlet line with two weak satellites due to the splitting on the 125 Te nucleus. Two-component relativistic DFT calculations perfectly reproduce the a(14 N) HFI constants and A∥ (125 Te) value responsible for the low-temperature satellite splitting. Calculations predict that the additional electron in 1.- is localised mainly on L, while the spin density is delocalised over the whole molecule with significant localisation on the Te atom (≥30 %). All these data suggest that 1.- can be regarded as the first example of a structurally characterised monomeric tellurium-nitrogen radical anion.
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Affiliation(s)
- Pavel A Petrov
- Nikolaev Institute of Inorganic Chemistry SB RAS, Lavrentiev Av. 3, 630090, Novosibirsk, Russia
| | - Evgeny M Kadilenko
- Novosibirsk State University, Pirogova St. 2, 630090, Novosibirsk, Russia.,Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Institutskaya St. 3, 630090, Novosibirsk, Russia
| | - Taisiya S Sukhikh
- Nikolaev Institute of Inorganic Chemistry SB RAS, Lavrentiev Av. 3, 630090, Novosibirsk, Russia
| | - Ilia V Eltsov
- Novosibirsk State University, Pirogova St. 2, 630090, Novosibirsk, Russia
| | - Artem L Gushchin
- Nikolaev Institute of Inorganic Chemistry SB RAS, Lavrentiev Av. 3, 630090, Novosibirsk, Russia
| | - Vladimir A Nadolinny
- Nikolaev Institute of Inorganic Chemistry SB RAS, Lavrentiev Av. 3, 630090, Novosibirsk, Russia
| | - Maxim N Sokolov
- Nikolaev Institute of Inorganic Chemistry SB RAS, Lavrentiev Av. 3, 630090, Novosibirsk, Russia
| | - Nina P Gritsan
- Novosibirsk State University, Pirogova St. 2, 630090, Novosibirsk, Russia.,Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Institutskaya St. 3, 630090, Novosibirsk, Russia
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86
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Chatterjee B, Chang WC, Jena S, Werlé C. Implementation of Cooperative Designs in Polarized Transition Metal Systems—Significance for Bond Activation and Catalysis. ACS Catal 2020. [DOI: 10.1021/acscatal.0c03794] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Basujit Chatterjee
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
- Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany
| | - Wei-Chieh Chang
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
- Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany
| | - Soumyashree Jena
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
- Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany
| | - Christophe Werlé
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
- Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany
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87
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Nasibipour M, Safaei E, Wojtczak A, Jagličić Z, Galindo A, Masoumpour MS. A biradical oxo-molybdenum complex containing semiquinone and o-aminophenol benzoxazole-based ligands. RSC Adv 2020; 10:40853-40866. [PMID: 35519205 PMCID: PMC9059147 DOI: 10.1039/d0ra06351g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 10/16/2020] [Indexed: 12/27/2022] Open
Abstract
We report a new mononuclear molybdenum(iv) complex, MoOLBISLSQ, in which LSQ (2,4-di-tert-butyl o-semibenzoquinone ligand) has been prepared from the reaction of the o-iminosemibenzoquinone form of a tridentate non-innocent benzoxazole ligand, LBIS, and MoO2(acac)2. The complex was characterized by X-ray crystallography, elemental analysis, IR and UV-vis spectroscopy and magnetic susceptibility measurements. The crystal structure of MoOLBISLSQ revealed a distorted octahedral geometry around the metal centre, surrounded by one O and two N atoms of LBIS and two O atoms of LSQ. The effective magnetic moment (μ eff) of MoOLBISLSQ decreased from 2.36 to 0.2 μB in the temperature range of 290 to 2 K, indicating a singlet ground state caused by antiferromagnetic coupling between the metal and ligand centred unpaired electrons. Also, the latter led to the EPR silence of the complex. Cyclic voltammetry (CV) studies indicate both ligand and metal-centered redox processes. MoOLBISLSQ was applied as a catalyst for the oxidative cleavage of cyclohexene to adipic acid and selective oxidation of sulfides to sulfones with aqueous hydrogen peroxide.
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Affiliation(s)
- Mina Nasibipour
- Department of Chemistry, College of Sciences, Shiraz University 71454 Shiraz Iran
| | - Elham Safaei
- Department of Chemistry, College of Sciences, Shiraz University 71454 Shiraz Iran
| | - Andrzej Wojtczak
- Nicolaus Copernicus University, Faculty of Chemistry 87-100 Torun Poland
| | - Zvonko Jagličić
- Institute of Mathematics, Physics and Mechanics & Faculty of Civil and Geodetic Engineering, University of Ljubljana Jadranska 19 Ljubljana Slovenia
| | - Agustín Galindo
- Departamento de Química Inorgánica, Facultad de Química, Universidad de Sevilla Aptdo. 1203 41071 Sevilla Spain
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88
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Maier TM, Gawron M, Coburger P, Bodensteiner M, Wolf R, van Leest NP, de Bruin B, Demeshko S, Meyer F. Low-Valence Anionic α-Diimine Iron Complexes: Synthesis, Characterization, and Catalytic Hydroboration Studies. Inorg Chem 2020; 59:16035-16052. [PMID: 33078926 DOI: 10.1021/acs.inorgchem.0c02606] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The synthesis of rare anionic heteroleptic and homoleptic α-diimine iron complexes is described. Heteroleptic BIAN (bis(aryl)iminoacenaphthene) complexes 1-[K([18]c-6)(thf)0.5] and 2-[K([18]c-6)(thf)2] were synthesized by reduction of the [(BIAN)FeBr2] precursor complex using stoichiometric amounts of potassium graphite in the presence of the corresponding olefin. The electronic structure of these paramagnetic species was investigated by numerous spectroscopic analyses (NMR, EPR, 57Fe Mössbauer, UV-vis), magnetic measurements (Evans NMR method, SQUID), and theoretical techniques (DFT, CASSCF). Whereas anion 1 is a low-spin complex, anion 2 consists of an intermediate-spin Fe(III) center. Both complexes are efficient precatalysts for the hydroboration of carbonyl compounds under mild reaction conditions. The reaction of bis(anthracene) ferrate(1-) gave the homoleptic BIAN complex 3-[K([18]c-6)(thf)], which is less catalytically active. The electronic structure was elucidated with the same techniques as described for complexes 1-[K([18]c-6)(thf)0.5] and 2-[K([18]c-6)(thf)2] and revealed an Fe(II) species in a quartet ground state.
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Affiliation(s)
- Thomas M Maier
- Institute of Inorganic Chemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Martin Gawron
- Institute of Inorganic Chemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Peter Coburger
- Institute of Inorganic Chemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Michael Bodensteiner
- Institute of Inorganic Chemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Robert Wolf
- Institute of Inorganic Chemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Nicolaas P van Leest
- van 't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bas de Bruin
- van 't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Serhiy Demeshko
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Franc Meyer
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany.,International Center for Advanced Studies of Energy Conversion (ICASEC), University of Göttingen, Tammannstrasse 6, Göttingen 37077, Germany
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89
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Kim J, Kim D, Chang S. Merging Two Functions in a Single Rh Catalyst System: Bimodular Conjugate for Light-Induced Oxidative Coupling. J Am Chem Soc 2020; 142:19052-19057. [PMID: 33124802 DOI: 10.1021/jacs.0c09982] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A single molecular rhodium catalyst system (PC2-Cp#RhIII) bearing two functional domains for both photosensitization and C-H carbometalation was designed to enable an intramolecular redox process. The hypothesized charge-transfer species (PC2•--Cp#RhIV) was characterized by spectroscopic and electrochemical analyses. This photoinduced internal oxidation allows a facile access to the triplet state of the key post-transmetalation intermediate that readily undergoes C-C bond-forming reductive elimination with a lower activation barrier than in its singlet state, thus enabling catalytic C-H arylation and methylation processes.
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Affiliation(s)
- Jinwoo Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea.,Center for Catalytic Hydrocarbon Functionalization, Institute for Basic Science (IBS), Daejeon 34141, South Korea
| | - Dongwook Kim
- Center for Catalytic Hydrocarbon Functionalization, Institute for Basic Science (IBS), Daejeon 34141, South Korea
| | - Sukbok Chang
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea.,Center for Catalytic Hydrocarbon Functionalization, Institute for Basic Science (IBS), Daejeon 34141, South Korea
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90
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Ershova IV, Piskunov AV, Cherkasov VK. Complexes of diamagnetic cations with radical anion ligands. RUSSIAN CHEMICAL REVIEWS 2020. [DOI: 10.1070/rcr4957] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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91
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Arczyński M, Pinkowicz D. Influence of the Increasing Number of Organic Radicals on the Structural, Magnetic, and Electrochemical Properties of the Copper(II)-Dioxothiadiazole Family of Complexes. Inorg Chem 2020; 59:13489-13501. [PMID: 32907320 PMCID: PMC7509843 DOI: 10.1021/acs.inorgchem.0c01904] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Indexed: 01/17/2023]
Abstract
The preparation, structures, and electrochemical and magnetic properties supported by density functional theory (DFT) calculations of three new copper(II) compounds with [1,2,5]thiadiazolo[3,4-f][1,10]phenanthroline 1,1-dioxide (td) and its radical anion (td·-) are reported: {[CuIICl(td)](μ-Cl)2[CuIICl(td)]} (1), which incorporates only neutral td ligands; [CuIICl(td·-)(td)]·2MeCN (2), which comprises one neutral td and one radical td·-; and PPN[CuIICl(td·-)2]·2DMA (3), where CuII ions are coordinated by two radical anions td·- (DMA, dimethylacetamide; PPN+, the bis(triphenylphosphine)iminium cation). All three compounds show interesting paramagnetic behavior with low-temperature features indicating significant antiferromagnetic coupling. The magnetic properties of 1 are dominated by CuII···CuII interactions (JCuCu) mediated through the Cl- bridges, while the magnetic properties of 2 and 3 are governed mainly by the td·-···td·- (Jtdtd) and CuII-td·- (JCutd) exchange interactions. The structure of 2 features only two major magnetic coupling pathways enabling the fitting of experimental data with Jtdtd = -36.0(5) cm-1 and JCutd = -12.6(2) cm-1 only. Compound 3 exhibits a complex network of magnetic contacts. Attempt to approximate its magnetic behavior using only a local magnetic contacts model resulted in Jtdtd = -5.6(1) cm-1 and two JCutd constants, -12.4(2) and -22.6(4) cm-1. The experimental fitting is critically compared with the results of broken symmetry density functional theory (BS DFT) calculations for inter- and intramolecular contacts. More consistent results were obtained with the M06 functional as opposed to popular B3LYP, which encountered problems reproducing some of the experimental intermolecular exchange interactions. Electrochemical measurements of 2 and 3 in MeCN showed three reversible nearly overlapping redox peaks appearing in a narrow potential range of -600 to -100 mV vs Fc/Fc+. Small differences between the redox events suggest that such compounds may be good candidates for new switchable materials, where the electron transfer between the metal and the ligand center is triggered by temperature, pressure, or light (valence tautomerism).
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Affiliation(s)
- Mirosław Arczyński
- Jagiellonian University, Faculty of Chemistry, Gronostajowa 2, 30-387 Kraków, Poland
| | - Dawid Pinkowicz
- Jagiellonian University, Faculty of Chemistry, Gronostajowa 2, 30-387 Kraków, Poland
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92
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Witzke RJ, Chapovetsky A, Conley MP, Kaphan DM, Delferro M. Nontraditional Catalyst Supports in Surface Organometallic Chemistry. ACS Catal 2020. [DOI: 10.1021/acscatal.0c03350] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ryan J. Witzke
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Alon Chapovetsky
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Matthew P. Conley
- Department of Chemistry, University of California, Riverside, Riverside, California 92521, United States
| | - David M. Kaphan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Massimiliano Delferro
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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93
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van
Leest NP, Stroek W, Siegler MA, van der Vlugt JI, Bruin BD. Ligand-Mediated Spin-State Changes in a Cobalt-Dipyrrin-Bisphenol Complex. Inorg Chem 2020; 59:12903-12912. [PMID: 32815718 PMCID: PMC7482399 DOI: 10.1021/acs.inorgchem.0c01979] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Indexed: 12/20/2022]
Abstract
The influence of a redox-active ligand on spin-changing events induced by the coordination of exogenous donors is investigated within the cobalt complex [CoII(DPP·2-)], bearing a redox-active DPP2- ligand (DPP = dipyrrin-bis(o,p-di-tert-butylphenolato) with a pentafluorophenyl moiety on the meso-position. This square-planar complex was subjected to the coordination of tetrahydrofuran (THF), pyridine, tBuNH2, and AdNH2 (Ad = 1-adamantyl), and the resulting complexes were analyzed with a variety of experimental (X-ray diffraction, NMR, UV-visible, high-resolution mass spectrometry, superconducting quantum interference device, Evans' method) and computational (density functional theory, NEVPT2-CASSCF) techniques to elucidate the respective structures, spin states, and orbital compositions of the corresponding octahedral bis-donor adducts, relative to [CoII(DPP·2-)]. This starting species is best described as an open-shell singlet complex containing a DPP·2- ligand radical that is antiferromagnetically coupled to a low-spin (S = 1/2) cobalt(II) center. The redox-active DPPn- ligand plays a crucial role in stabilizing this complex and in its facile conversion to the triplet THF adduct [CoII(DPP·2-)(THF)2] and closed-shell singlet pyridine and amine adducts [CoIII(DPP3-)(L)2] (L = py, tBuNH2, or AdNH2). Coordination of the weak donor THF to [CoII(DPP·2-)] changes the orbital overlap between the DPP·2- ligand radical π-orbitals and the cobalt(II) metalloradical d-orbitals, which results in a spin-flip to the triplet ground state without changing the oxidation states of the metal or DPP·2- ligand. In contrast, coordination of the stronger donors pyridine, tBuNH2, or AdNH2 induces metal-to-ligand single-electron transfer, resulting in the formation of low-spin (S = 0) cobalt(III) complexes [CoIII(DPP3-)(L)2] containing a fully reduced DPP3- ligand, thus explaining their closed-shell singlet electronic ground states.
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Affiliation(s)
- Nicolaas P. van
Leest
- Homogeneous, Supramolecular
and Bio-Inspired Catalysis Group, van’t Hoff Institute for
Molecular Sciences, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - Wowa Stroek
- Homogeneous, Supramolecular
and Bio-Inspired Catalysis Group, van’t Hoff Institute for
Molecular Sciences, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - Maxime A. Siegler
- Department of Chemistry, John Hopkins University, Baltimore 21218, Maryland, United States
| | - Jarl Ivar van der Vlugt
- Homogeneous, Supramolecular
and Bio-Inspired Catalysis Group, van’t Hoff Institute for
Molecular Sciences, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - Bas de Bruin
- Homogeneous, Supramolecular
and Bio-Inspired Catalysis Group, van’t Hoff Institute for
Molecular Sciences, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
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94
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Fomenko IS, Gushchin AL. Mono- and binuclear complexes of group 5 metals with diimine ligands: synthesis, reactivity and prospects for application. RUSSIAN CHEMICAL REVIEWS 2020. [DOI: 10.1070/rcr4949] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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95
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Liu S, Légaré MA, Seufert J, Prieschl D, Rempel A, Englert L, Dellermann T, Paprocki V, Stoy A, Braunschweig H. 2,2′-Bipyridyl as a Redox-Active Borylene Abstraction Agent. Inorg Chem 2020; 59:10866-10873. [DOI: 10.1021/acs.inorgchem.0c01383] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Siyuan Liu
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Marc-André Légaré
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Jens Seufert
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Dominic Prieschl
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Anna Rempel
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Lukas Englert
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Theresa Dellermann
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Valerie Paprocki
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Andreas Stoy
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Holger Braunschweig
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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96
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Spielvogel KD, Luna JA, Loria SM, Weisburn LP, Stumme NC, Ringenberg MR, Durgaprasad G, Keith JM, Shaw SK, Daly SR. Influence of Multisite Metal-Ligand Cooperativity on the Redox Activity of Noninnocent N 2S 2 Ligands. Inorg Chem 2020; 59:10845-10853. [PMID: 32639726 DOI: 10.1021/acs.inorgchem.0c01353] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Metal-ligand cooperativity (MLC) relies on chemically reactive ligands to assist metals with small-molecule binding and activation, and it has facilitated unprecedented examples of catalysis with metal complexes. Despite growing interest in combining ligand-centered chemical and redox reactions for chemical transformations, there are few studies demonstrating how chemically engaging redox active ligands in MLC affects their electrochemical properties when bound to metals. Here we report stepwise changes in the redox activity of model Ru complexes as zero, one, and two BH3 molecules undergo MLC binding with a triaryl noninnocent N2S2 ligand derived from o-phenylenediamine (L1). A similar series of Ru complexes with a diaryl N2S2 ligand with ethylene substituted in place of phenylene (L2) is also described to evaluate the influence of the o-phenylenediamine subunit on redox activity and MLC. Cyclic voltammetry (CV) studies and density functional theory (DFT) calculations show that MLC attenuates ligand-centered redox activity in both series of complexes, but electron transfer is still achieved when only one of the two redox-active sites on the ligands is chemically engaged. The results demonstrate how incorporating more than one multifunctional reactive site could be an effective strategy for maintaining redox noninnocence in ligands that are also chemically reactive and competent for MLC.
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Affiliation(s)
- Kyle D Spielvogel
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242, United States
| | - Javier A Luna
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242, United States
| | - Sydney M Loria
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Leah P Weisburn
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Nathan C Stumme
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242, United States
| | - Mark R Ringenberg
- Universität Stuttgart, Institut für Anorganische Chemie, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Gummadi Durgaprasad
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242, United States
| | - Jason M Keith
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Scott K Shaw
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242, United States
| | - Scott R Daly
- Department of Chemistry, The University of Iowa, E331 Chemistry Building, Iowa City, Iowa 52242, United States
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97
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Greb L, Ebner F, Ginzburg Y, Sigmund LM. Element‐Ligand Cooperativity with p‐Block Elements. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000449] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Lutz Greb
- Anorganisch‐Chemisches Institut Ruprecht‐Karls‐Universität Heidelberg Im Neuenheimer Feld 275 69120 Heidelberg Germany
| | - Fabian Ebner
- Anorganisch‐Chemisches Institut Ruprecht‐Karls‐Universität Heidelberg Im Neuenheimer Feld 275 69120 Heidelberg Germany
| | - Yael Ginzburg
- Anorganisch‐Chemisches Institut Ruprecht‐Karls‐Universität Heidelberg Im Neuenheimer Feld 275 69120 Heidelberg Germany
| | - Lukas M. Sigmund
- Anorganisch‐Chemisches Institut Ruprecht‐Karls‐Universität Heidelberg Im Neuenheimer Feld 275 69120 Heidelberg Germany
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98
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Sinha S, Das S, Mondal R, Mandal S, Paul ND. Cobalt complexes of redox noninnocent azo-aromatic pincers. Isolation, characterization, and application as catalysts for the synthesis of quinazolin-4(3H)-ones. Dalton Trans 2020; 49:8448-8459. [PMID: 32239054 DOI: 10.1039/d0dt00394h] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein we report the synthesis, characterization and catalytic application of three new cobalt(ii)-complexes of redox noninnocent arylazo ligands, 2-(phenylazo)-1,10-phenanthroline (L1a), 2-(4-chlorophenylazo)-1,10-phenanthroline (L1b) and 2,9-bis(phenyldiazo)-1,10-phenanthroline (L2) respectively. The reaction of L1a with CoIICl2·6H2O produced a μ-dichloro bridged binuclear cobalt(ii)-complex [Co(L1a)2Cl2] (1a) while the same reaction when carried out with 2-(4-chlorophenyl)azo-1,10-phenanthroline (L1b) and 2,9-bis(phenyldiazo)-1,10-phenanthroline (L2) ligands produced two new mononuclear five-coordinate cobalt(ii)-complexes 1b and 2 respectively. In complex 1a and 1b, the ligands L1a and L1b are coordinated to the cobalt(ii)-center in a tridentate mode utilizing all of its nitrogen donor sites while in complex 2 one of the azo-donor sites of the ligand L2 remain pendant. All these complexes were characterized using available spectroscopic techniques and DFT studies. We further explored the potential of these complexes as catalysts for the synthesis of pharmaceutically important organic compounds via the functionalization of alcohols. A variety of substituted quinazolin-4(3H)-ones were synthesized under aerobic conditions via the coupling of alcohols and 2-aminobenzamide using 1b as the catalyst. Mechanistic investigations revealed that both cobalt and the arylazo scaffold act synergistically during catalysis.
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Affiliation(s)
- Suman Sinha
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah 711103, India.
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99
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Bauer S, Záliš S, Fiedler J, Ringenberg MR, Kaim W. Oxidation State Assignments in the Organoplatinum One‐Electron Redox Series [(N
^
N)PtMes
2
]
n
,
n
= +,0, –,2‐. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000257] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Sonja Bauer
- Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 70550 Stuttgart Germany
| | - Stanislav Záliš
- J. Heyrovský Institute of Physical Chemistry The Czech Academy of Sciences Dolejškova 3 18223 Prague Czech Republic
| | - Jan Fiedler
- J. Heyrovský Institute of Physical Chemistry The Czech Academy of Sciences Dolejškova 3 18223 Prague Czech Republic
| | - Mark R. Ringenberg
- Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 70550 Stuttgart Germany
| | - Wolfgang Kaim
- Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 70550 Stuttgart Germany
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100
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Nasibipour M, Safaei E, Masoumpour MS, Wojtczak A. Ancillary ligand electro-activity effects towards phenyl acetylene homocoupling reaction by a nickel(ii) complex of a non-innocent O-amino phenol ligand: a mechanistic insight. RSC Adv 2020; 10:24176-24189. [PMID: 35516191 PMCID: PMC9055111 DOI: 10.1039/d0ra04362a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 05/27/2020] [Indexed: 11/21/2022] Open
Abstract
A new Ni(ii) complex, was synthesized from the reaction of a non-innocent o-aminophenol ligand, and Ni(OAc)2. The crystal structure of NiIIL2 NIS (in which, IS stands for iminosemiquinone radical ligand with cyanide (shown by N in NIS) substituent on phenolate rings) exhibits the square planar environment of Ni(ii). The complex has been crystalized in the monoclinic system and Ni(ii) was surrounded by two oxygen and two nitrogen atoms of two ligands. Variable-temperature magnetic susceptibility measurement for crystalline samples of complex shows the effective magnetic moment per molecule (μ eff) of near zero and the diamagnetic nature of the complex (S = 0) which emphasize that strong antiferromagnetic coupling prevailed between the two unpaired electrons of LNIS ligands and Ni(ii) high spin electrons. The complex is EPR silent which confirms the diamagnetic character of the Ni(ii) complex. Electrochemical measurement (CV) indicates the redox-active character of ligand and metal. NiIIL2 NIS complex proved to be effective for free metal- or base counterpart homocoupling of phenyl acetylene at room temperature. To the best of our knowledge, this is the first example of using Ni(ii) complex without using any reducing agent due to the promotion ancillary effect of non-innocent o-aminophenol ligand which acts as an "electron reservoir" and can reversibly accept and donate electrons in the catalytic cycle. The theoretical calculation confirms the magnetostructure, electronic spectrum and confirmed the suggested mechanism of phenyl acetylene homocoupling with emphasis on the role of non-innocent ligand electro-activity and the effect of ligand substituent on the efficiency and stability of the complex.
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Affiliation(s)
- Mina Nasibipour
- Department of Chemistry, College of Sciences, Shiraz University 71454 Shiraz Iran
| | - Elham Safaei
- Department of Chemistry, College of Sciences, Shiraz University 71454 Shiraz Iran
| | | | - Andrzej Wojtczak
- Nicolaus Copernicus University, Faculty of Chemistry 87-100 Torun Poland
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