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Golwankar RR, Kumar A, Day VW, Blakemore JD. Revealing the Influence of Diverse Secondary Metal Cations on Redox‐Active Palladium Complexes. Chemistry 2022; 28:e202200344. [DOI: 10.1002/chem.202200344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Indexed: 11/09/2022]
Affiliation(s)
- Riddhi R. Golwankar
- Department of Chemistry University of Kansas 1567 Irving Hill Road Lawrence Kansas 66045 USA
| | - Amit Kumar
- Department of Chemistry University of Kansas 1567 Irving Hill Road Lawrence Kansas 66045 USA
- Current address: Department of Chemistry University of Pennsylvania Philadelphia Pennsylvania 19104 USA
| | - Victor W. Day
- Department of Chemistry University of Kansas 1567 Irving Hill Road Lawrence Kansas 66045 USA
| | - James D. Blakemore
- Department of Chemistry University of Kansas 1567 Irving Hill Road Lawrence Kansas 66045 USA
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2
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Gradiski MV, Rennie BE, Lough AJ, Morris RH. Electronic insights into aminoquinoline-based PN HN ligands: protonation state dictates geometry while coordination environment dictates N-H acidity and bond strength. Dalton Trans 2022; 51:11241-11254. [PMID: 35731231 DOI: 10.1039/d2dt01556k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A variety of transition metal complexes bearing aminoquinoline PNHH'-R ligands R = Ph (L1H), Cy (L2H) and their amido analogues are reported for rhodium(I) ([Rh(L1H)(PPh3)]+1 and Rh(L1)(PPh3) 2), cobalt(II) (Co(L2)(Cl) 3), and iron(II) ([Fe(L1H)2]2+5, Fe(L1)26, and [Fe(C5Me5)(L1H)]PF67). The acid-base and redox properties of the amido complexes 2, 6, and their protio parent complexes 1, and 5 permit the determination of the pKa and bond dissociation free energy (BDFE) of their N-H bonds while the ligand scaffold is coordinated to metal centres of square planar and octahedral geometry, respectively. From relative concentrations obtained by the use of 31P{1H} NMR spectroscopy, a pKaTHF value of 14 is calculated for rhodium complex 1, 6.4 for iron complex 5, and 24 for iron complex 7. These data, when combined with elecrochemical potentials obtained via cyclic voltammetry, allow the calculations of BDFE values for the N-H bond of 69 kcal mol-1 for 1, and of 55 kcal mol-1 for 5.
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Affiliation(s)
- Matthew V Gradiski
- Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario, M5S 3H6, Canada.
| | - Benjamin E Rennie
- Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario, M5S 3H6, Canada.
| | - Alan J Lough
- Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario, M5S 3H6, Canada.
| | - Robert H Morris
- Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario, M5S 3H6, Canada.
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3
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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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4
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Erickson AN, Gianino J, Markovitz SJ, Brown SN. Amphiphilicity in Oxygen Atom Transfer Reactions of Oxobis(iminoxolene)osmium Complexes. Inorg Chem 2021; 60:4004-4014. [PMID: 33657323 DOI: 10.1021/acs.inorgchem.1c00068] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Oxobis(iminoxolene)osmium(VI) compounds (Rap)2OsO (Rap = 2-(4-RC6H4N)-4,6-tBu2C6H2O) are readily deoxygenated by phosphines and phosphites to give five-coordinate (Rap)2Os(PR'3) or six-coordinate (Rap)2Os(PR'3)2. Structural data indicate that this net two-electron reduction is accompanied by apparent oxidation of the iminoxolene ligands due to their greater ability to engage in π donation to the reduced deoxy form of the osmium complex. In (Rap)2Os(PR'3)2, the HOMO is a ligand-based combination of the iminoxolene redox-active orbitals, while the LUMO is a highly covalent metal-iminoxolene π* orbital. In the trans isomer, the HOMO is required to be ligand-localized by symmetry, while in the cis isomer, the ligands adopt a conformation that minimizes metal-ligand π* interactions in the HOMO. Kinetic studies indicate that the deoxygenations involve the rate-determining attack of the phosphorus(III) reagent on the five-coordinate oxo complexes. Varying the substituents of the aryl groups on the iminoxolene ligands or on the triarylphosphines has little effect on the rate of oxygen atom transfer, with the best correlation shown between oxygen atom transfer rates and the HOMO-LUMO gap of the oxo complexes. This suggests that the osmium oxo group shows a balance between electrophilic and nucleophilic character in its oxygen atom transfer reactions with phosphorus(III) reagents.
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Affiliation(s)
- Alexander N Erickson
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, United States
| | - Jacqueline Gianino
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, United States
| | - Sean J Markovitz
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, United States
| | - Seth N Brown
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, United States
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5
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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] [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 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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Charette BJ, Ziller JW, Heyduk AF. Metal-Ion Influence on Ligand-Centered Hydrogen-Atom Transfer. Inorg Chem 2021; 60:1579-1589. [PMID: 33434022 DOI: 10.1021/acs.inorgchem.0c02981] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ligand-centered hydrogen-atom-transfer (HAT) reactivity was examined for a family of group 10 metal complexes containing a tridentate pincer ligand derived from bis(2-mercapto-p-tolyl)amine, [SNS]H3. Six new metal complexes of palladium and platinum were synthesized with the [SNS] ligand platform in different redox and protonation states to complete the group 10 series previously reported with nickel. The HAT reactivity was examined for this family of nickel, palladium, and platinum complexes to determine the impact of a metal ion on the ligand-centered reactivity. Thermodynamic measurements revealed that N-H bond dissociation free energies increased by approximately 10 kcal mol-1 along the series Ni < Pd < Pt driven by changes to both the redox potential and pKa of the ligand. Kinetic analyses for all three metal complexes suggest that the barrier to the HAT reactivity is primarily entropic rather than enthalpic for this system.
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Affiliation(s)
- Bronte J Charette
- Department of Chemistry, University of California at Irvine (UCI), Irvine, California 92677-2025, United States
| | - Joseph W Ziller
- Department of Chemistry, University of California at Irvine (UCI), Irvine, California 92677-2025, United States
| | - Alan F Heyduk
- Department of Chemistry, University of California at Irvine (UCI), Irvine, California 92677-2025, United States
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Sinitsa DK, Sukhikh TS, Konchenko SN, Pushkarevsky NA. Synthesis, structures, and one- or two-electron reduction reactivity of mononuclear lanthanide (Ho, Dy) complexes with sterically hindered o-iminobenzoquinone ligands. Polyhedron 2021. [DOI: 10.1016/j.poly.2020.114967] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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8
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Stuyver T, Chen B, Zeng T, Geerlings P, De Proft F, Hoffmann R. Do Diradicals Behave Like Radicals? Chem Rev 2019; 119:11291-11351. [DOI: 10.1021/acs.chemrev.9b00260] [Citation(s) in RCA: 139] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Thijs Stuyver
- Algemene Chemie, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Bo Chen
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca New York 14853, United States
| | - Tao Zeng
- Department of Chemistry, York University, Toronto, Ontario M3J1P3, Canada
- Department of Chemistry, Carleton University, Ottawa, Ontario K1S5B6, Canada
| | - Paul Geerlings
- Algemene Chemie, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Frank De Proft
- Algemene Chemie, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Roald Hoffmann
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca New York 14853, United States
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9
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Sanz CA, Patrick BO, Hicks RG. Synthesis and redox chemistry of Pd(ii) complexes of a pincer verdazyl ligand. Dalton Trans 2019; 48:12674-12683. [PMID: 31384845 DOI: 10.1039/c9dt02549a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of palladium(ii) complexes containing a redox-active, tridentate verdazyl ligand of general formula (verdazyl)PdL (L = Cl, CH3CN) are synthesized. The tetrazine core of tridentate verdazyl ligand 5 is flanked by two pyridyl groups, creating a geometry in which the ancillary ligand L is bound trans to the verdazyl ring in the square planar metal complexes. Pd(ii) complexes were isolated with the verdazyl ligand in either its neutral radical charge state (6: L = CH3CN, 12: L = Cl) or its closed-shell monoanionic charge state (10: L = CH3CN, 9: L = Cl). The charge state of the ligand was determined using X-ray crystallography and NMR, EPR, and IR spectroscopy. The cyclic voltammograms of radical complexes 6 and 12 each contain a reversible one-electron reduction wave and an irreversible one-electron oxidation wave. The complexes can be chemically interconverted between radical ligand (6, 12) and reduced, closed-shell anion (9, 10) using decamethylferrocene as the reductant and a mixture of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and fluoroboric acid as the oxidant.
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Affiliation(s)
- Corey A Sanz
- Department of Chemistry, University of Victoria, PO Box 3065 STN CSC, Victoria, B.C. V8W3V6, Canada.
| | - Brian O Patrick
- Crystallography Laboratory, Department of Chemistry, University of British Columbia, Vancouver, BC V6T1Z1, Canada
| | - Robin G Hicks
- Department of Chemistry, University of Victoria, PO Box 3065 STN CSC, Victoria, B.C. V8W3V6, Canada.
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van der Vlugt JI. Radical-Type Reactivity and Catalysis by Single-Electron Transfer to or from Redox-Active Ligands. Chemistry 2019; 25:2651-2662. [PMID: 30084211 PMCID: PMC6471147 DOI: 10.1002/chem.201802606] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Indexed: 12/12/2022]
Abstract
Controlled ligand-based redox-activity and chemical non-innocence are rapidly gaining importance for selective (catalytic) processes. This Concept aims to provide an overview of the progress regarding ligand-to-substrate single-electron transfer as a relatively new mode of operation to exploit ligand-centered reactivity and catalysis based thereon.
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Affiliation(s)
- Jarl Ivar van der Vlugt
- Bio-Inspired Homogeneous and Supramolecular Catalysis Groupvan ‘t Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041098 XHAmsterdamNetherlands
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11
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Safaei E, Balaghi SE, Chiang L, Clarke RM, Martelino D, Webb MI, Wong EWY, Savard D, Walsby CJ, Storr T. Stabilization of different redox levels of a tridentate benzoxazole amidophenoxide ligand when bound to Co(iii) or V(v). Dalton Trans 2019; 48:13326-13336. [DOI: 10.1039/c9dt02865j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The electronic structure of Co and V complexes of a tridentate benzoxazole-containing aminophenol ligand NNOH2 were characterized by both experimental and theoretical methods.
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Affiliation(s)
- Elham Safaei
- Department of Chemistry
- College of Science
- Shiraz University
- Shiraz
- Iran
| | | | - Linus Chiang
- Department of Chemistry
- Simon Fraser University
- 8888 University Drive
- Burnaby
- Canada
| | - Ryan M. Clarke
- Department of Chemistry
- Simon Fraser University
- 8888 University Drive
- Burnaby
- Canada
| | - Diego Martelino
- Department of Chemistry
- Simon Fraser University
- 8888 University Drive
- Burnaby
- Canada
| | - Michael I. Webb
- Department of Chemistry
- Simon Fraser University
- 8888 University Drive
- Burnaby
- Canada
| | - Edwin W. Y. Wong
- Department of Chemistry
- Simon Fraser University
- 8888 University Drive
- Burnaby
- Canada
| | - Didier Savard
- Department of Chemistry
- Simon Fraser University
- 8888 University Drive
- Burnaby
- Canada
| | - Charles J. Walsby
- Department of Chemistry
- Simon Fraser University
- 8888 University Drive
- Burnaby
- Canada
| | - Tim Storr
- Department of Chemistry
- Simon Fraser University
- 8888 University Drive
- Burnaby
- Canada
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12
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Coordination chemistry of a redox non-innocent NHC bis(phenolate) pincer ligand with nickel(II). Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2018.06.046] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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13
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Rosenkoetter KE, Wojnar MK, Charette BJ, Ziller JW, Heyduk AF. Hydrogen-Atom Noninnocence of a Tridentate [SNS] Pincer Ligand. Inorg Chem 2018; 57:9728-9737. [DOI: 10.1021/acs.inorgchem.8b00618] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Kyle E. Rosenkoetter
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Michael K. Wojnar
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Bronte J. Charette
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Joseph W. Ziller
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Alan F. Heyduk
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
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