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Abstract
The nickel(II) complex [ON(H)O]Ni(PPh3) ([ON(H)O]2- = bis(3,5-di-tert-butyl-2-phenoxy)amine), bearing a protonated redox-active ligand, was examined for its ability to serve as a hydrogen atom (H•) and hydride (H-) donor. Deprotonation of [ON(H)O]Ni(PPh3) afforded the square-planar anion {[ONOcat]Ni(PPh3)}1-, whereas hydrogen atom transfer from [ON(H)O]Ni(PPh3) to TEMPO• in the presence of added PPh3 afforded five-coordinate [ONO]Ni(PPh3)2 that has been structurally characterized. In solution, this five-coordinate complex exists in equilibrium with four-coordinate [ONO]Ni(PPh3), and this ligand exchange equilibrium correlates with a valence tautomerization between the redox-active ligand and the nickel center. Abstraction of a hydride from [ON(H)O]Ni(PPh3) in the presence of PPh3 afforded the octahedral complex, [ONOq]Ni(OTf)(PPh3)2, which was characterized as an S = 1, nickel(II) complex. Bond dissociation free energy (BDFE) and hydricity (ΔG°H-) measurements benchmark the thermodynamic propensity of this complex to participate in ligand-centered H• and H- transfer reactions.
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Affiliation(s)
- Bronte J Charette
- Department of Chemistry, University of California, Irvine, Irvine, California 92677-2025, United States
| | - Joseph W Ziller
- Department of Chemistry, University of California, Irvine, Irvine, California 92677-2025, United States
| | - Alan F Heyduk
- Department of Chemistry, University of California, Irvine, Irvine, California 92677-2025, United States
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2
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Kumari M, Bera SK, Lahiri GK. Noninnocence of the deprotonated 1,2-bis((1 H-pyrrol-2-yl)methylene)hydrazine bridge in diruthenium frameworks - a function of co-ligands. Dalton Trans 2021; 50:9891-9903. [PMID: 34196336 DOI: 10.1039/d1dt01488a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The article deals with the sensitive electronic forms in accessible redox states of structurally and spectroscopically authenticated deprotonated 1,2-bis((1H-pyrrol-2-yl)methylene)hydrazine (H2LR, R = H) or 1,2-bis((3,5-dimethyl-1H-pyrrol-2-yl)methylene)hydrazine (H2LR, R = Me), a BODIPY analogue bridged diruthenium complex as a function of varying ancillary ligands. It involved rac-(acac)2RuIII(μ-LR 2-)RuIII(acac)21a, R = H; 1b, R = Me (S = 1, acac = acetylacetonate), rac-[(bpy)2RuII(μ-L2-)RuII(bpy)2](ClO4)2 [2](ClO4)2 (S = 0, bpy = 2,2'-bipyridine) and diastereomeric [(pap)2RuII(μ-L2-)RuII(pap)2](ClO4)2meso-[3a](ClO4)2/rac-[3b](ClO4)2 (S = 0, pap = phenylazopyridine). The crystal structure established the linkage of the conjugated -C5[double bond, length as m-dash]N2-N3[double bond, length as m-dash]C6- central unit with the two terminal deprotonated pyrrole units of coordinated L2-. The bridging L2- in 1a, 1b, [2](ClO4)2, [3b](ClO4)2 and [3a](ClO4)2 was slightly twisted and planar with torsional angles of 41.54°, 42.91°, 37.38°, 35.33° and 0°, respectively, with regard to the central N2-N3 bond. The extent of twisting of the bridge followed an inverse relationship with the RuRu separation: 4.935/4.934 Å 1a/1b < 5.141 Å [2](ClO4)2 < 5.201 Å [3b](ClO4)2 < 5.351 Å [3a](ClO4)2. This is also attributed to the intermolecular ππ/CHπ interactions between the nearby aromatic rings of L and bpy or pap in [2](ClO4)2 or [3](ClO4)2, respectively. The multiple redox steps of the complexes varied appreciably based on the σ-donating (acac) and π-acidic (bpy, pap) characteristics of the ancillary ligands. Experimental (structure, EPR) and theoretical (DFT) evaluation pertaining to the electronic forms of 1n, 2n and 3n demonstrated the preferential involvement of L based frontier orbitals in electron transfer processes even in combination with the redox facile ruthenium ion. This in turn highlighted its redox non-innocent feature as in the case of well-documented metal coordinated quinonoid, formazanate, diimine (bpy), azo (pap) and β-diketiminate functions.
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Affiliation(s)
- Maya Kumari
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Sudip Kumar Bera
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
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3
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Margulieux GW, Kim S, Chirik PJ. Determination of the N-H Bond Dissociation Free Energy in a Pyridine(diimine)molybdenum Complex Prepared by Proton-Coupled Electron Transfer. Inorg Chem 2020; 59:15394-15401. [PMID: 33016073 DOI: 10.1021/acs.inorgchem.0c02382] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The pyridine(diimine)molybdenum bis(imido) complex (iPrPDI)Mo(═NTol)2 (Tol = 4-methylphenyl) was synthesized by the addition of 2 equiv of 4-methylphenylazide to the corresponding molybdenum benzene derivative, (iPrPDI)Mo(η6-C6H6) [iPrPDI = 2,6-(2,6-iPr2C6H3N═CMe)2C5H3N]. Protonation of (iPrPDI)Mo(═NTol)2 with 2,6-lutinidum triflate yielded a cationic molybdenum amido complex, [(iPrPDI)Mo(NHTol)(═NTol)][OTf], which was further transformed into the neutral molybdenum amido (iPrPDI)Mo(NHTol)(═NTol) by reduction with zinc powder. A series of spectroscopic, synthetic, and pKa determination studies along with electrochemical measurements by the protonation-reduction pathway were used to establish an N-H bond dissociation free energy (BDFE) between 65 and 69 kcal/mol for the molybdenum imido-amido compound, (iPrPDI)Mo(NHTol)(═NTol). Full-molecule density functional theory studies provided a computed value of 61 kcal/mol. By contrast, reduction of (iPrPDI)Mo(═NTol)2 with KC8 afforded the corresponding anionic molybdenum complex K[(iPrPDI)Mo(═NTol)2], which has a potassium cation intercalated with the pyridine and tolyl groups. Protonation of K[(iPrPDI)Mo(═NTol)2] with the weak amidinium acid [TBD(H)][BArF24] (TBD = triazabicyclodecene; BArF24 = B[3,5-(CF3)2C6H3]4) also produced the neutral molybdenum amido complex (iPrPDI)Mo(NHTol)(═NTol). Measurement of the pKa and oxidation potential of K[(iPrPDI)Mo(═NTol)2] provided a range of 69-73 kcal/mol for the N-H BDFE of (iPrPDI)Mo(NHTol)(═NTol), in good agreement with the protonation-reduction route and completing the square scheme. The similar pKa and redox potentials obtained from each pathway demonstrate that both sequences are energetically feasible for proton-coupled electron-transfer (PCET) events. This study on the determination of N-H BDFE of the molybdenum amido complex renders fundamental insight into the N2 reduction cycle by PCET.
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Affiliation(s)
- Grant W Margulieux
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Sangmin Kim
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Paul J Chirik
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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4
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Jori N, Falcone M, Scopelliti R, Mazzanti M. Carbon Dioxide Reduction by Multimetallic Uranium(IV) Complexes Supported by Redox-Active Schiff Base Ligands. Organometallics 2020. [DOI: 10.1021/acs.organomet.9b00792] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Nadir Jori
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Marta Falcone
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Rosario Scopelliti
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Marinella Mazzanti
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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5
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Khan FF, Chowdhury AD, Lahiri GK. Bond Activations Assisted by Redox Active Ligand Scaffolds. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000005] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Farheen Fatima Khan
- Department of Chemistry; Indian Institute of Technology Bombay; Powai 400076 Mumbai India
| | | | - Goutam Kumar Lahiri
- Department of Chemistry; Indian Institute of Technology Bombay; Powai 400076 Mumbai India
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6
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van der Vlugt JI. Redox-Active Pincer Ligands. TOP ORGANOMETAL CHEM 2020. [DOI: 10.1007/3418_2020_68] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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7
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Sakai K, Oisaki K, Kanai M. Identification of Bond‐Weakening Spirosilane Catalyst for Photoredox α‐C−H Alkylation of Alcohols. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201901253] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Kentaro Sakai
- Graduate School of Pharmaceutical SciencesThe University of Tokyo 7-3-1, Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Kounosuke Oisaki
- Graduate School of Pharmaceutical SciencesThe University of Tokyo 7-3-1, Hongo, Bunkyo-ku Tokyo 113-0033 Japan
| | - Motomu Kanai
- Graduate School of Pharmaceutical SciencesThe University of Tokyo 7-3-1, Hongo, Bunkyo-ku Tokyo 113-0033 Japan
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8
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Ishizuka T, Kogawa T, Makino M, Shiota Y, Ohara K, Kotani H, Nozawa S, Adachi SI, Yamaguchi K, Yoshizawa K, Kojima T. Formation of a Ruthenium(V)-Imido Complex and the Reactivity in Substrate Oxidation in Water through the Nitrogen Non-Rebound Mechanism. Inorg Chem 2019; 58:12815-12824. [PMID: 31553593 DOI: 10.1021/acs.inorgchem.9b01781] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A RuII-NH3 complex, 2, was oxidized through a proton-coupled electron transfer (PCET) mechanism with a CeIV complex in water at pH 2.5 to generate a RuV═NH complex, 5. Complex 5 was characterized with various spectroscopies, and the spin state was determined by the Evans method to be S = 1/2. The reactivity of 5 in substrate C-H oxidation was scrutinized in acidic water, using water-soluble organic substrates such as sodium ethylbenzene-sulfonate (EBS), which gave the corresponding 1-phenylethanol derivative as the product. In the substrate oxidation, complex 5 was converted to the corresponding RuIII-NH3 complex, 3. The formation of 1-phenylethanol derivative from EBS and that of 3 indicate that complex 5 as the oxidant does not perform nitrogen-atom transfer, in sharp contrast to other high-valent metal-imido complexes reported so far. Oxidation of cyclobutanol by 5 afforded only cyclobutanone as the product, indicating that the substrate oxidation by 5 proceeds through a hydride-transfer mechanism. In the kinetic analysis on the C-H oxidation, we observed kinetic isotope effects (KIEs) on the C-H oxidation with use of deuterated substrates and remarkably large solvent KIE (sKIE) in D2O. These positive KIEs indicate that the rate-determining step involves not only cleavage of the C-H bond of the substrate but also proton transfer from water molecules to 5. The unique hydride-transfer mechanism in the substrate oxidation by 5 is probably derived from the fact that the RuIV-NH2 complex (4) formed from 5 by 1e-/1H+ reduction is unstable and quickly disproportionates into 3 and 5.
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Affiliation(s)
- Tomoya Ishizuka
- Department of Chemistry , University of Tsukuba , 1-1-1 Tennoudai , Tsukuba , Ibaraki 305-8571 , Japan
| | - Taichi Kogawa
- Department of Chemistry , University of Tsukuba , 1-1-1 Tennoudai , Tsukuba , Ibaraki 305-8571 , Japan
| | - Misaki Makino
- Department of Chemistry , University of Tsukuba , 1-1-1 Tennoudai , Tsukuba , Ibaraki 305-8571 , Japan
| | - Yoshihito Shiota
- Institute for Materials Chemistry and Engineering , Kyushu University , Motooka, Nishi-Ku , Fukuoka 819-0395 , Japan
| | - Kazuaki Ohara
- Faculty of Pharmaceutical Sciences at Kagawa Campus , Tokushima Bunri University , 1314-1 Shido , Sanuki , Kagawa 769-2193 , Japan
| | - Hiroaki Kotani
- Department of Chemistry , University of Tsukuba , 1-1-1 Tennoudai , Tsukuba , Ibaraki 305-8571 , Japan
| | - Shunsuke Nozawa
- Photon Factory , Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK) , 1-1 Oho , Tsukuba , Ibaraki 305-0801 , Japan
| | - Shin-Ichi Adachi
- Photon Factory , Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK) , 1-1 Oho , Tsukuba , Ibaraki 305-0801 , Japan
| | - Kentaro Yamaguchi
- Faculty of Pharmaceutical Sciences at Kagawa Campus , Tokushima Bunri University , 1314-1 Shido , Sanuki , Kagawa 769-2193 , Japan
| | - Kazunari Yoshizawa
- Institute for Materials Chemistry and Engineering , Kyushu University , Motooka, Nishi-Ku , Fukuoka 819-0395 , Japan
| | - Takahiko Kojima
- Department of Chemistry , University of Tsukuba , 1-1-1 Tennoudai , Tsukuba , Ibaraki 305-8571 , Japan
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9
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Labrum NS, Caulton KG. [Cr(pincer 2-)] 2 as an electron shuttle for reductively promoted hydrazine disproportionation. Dalton Trans 2019; 48:11642-11646. [PMID: 31310268 DOI: 10.1039/c9dt02300c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
We describe here delivery of hydrazine to a reducing, low oxidation state chromium bound to a proton responsive ligand which has already been deprotonated. Reaction of PhHNNH2 at a 4 : 1 mole ratio with the bis-(pyrazolate)pyridyl pincer ligated reducing agent [CrIIL]2 gives prompt conversion to [CrL2(PhNH2)2(μ-PhHNN)], with release of NH3 and C6H6, a new disproportionation of the hydrazine, with trapping of PhHNN as its dianion, bridging the two chromium centers. The redox balance of the reaction is discussed, and participation by Brønsted basic sites on the bis-(pyrazolate)pyridyl pincer ligand L2- is suggested, but no hydrazine protons remain on the pincer in the product.
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10
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Kim J, Kim YE, Park K, Lee Y. A Silyl-Nickel Moiety as a Metal–Ligand Cooperative Site. Inorg Chem 2019; 58:11534-11545. [DOI: 10.1021/acs.inorgchem.9b01388] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jin Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Yeong-Eun Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Koeun Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Yunho Lee
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
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11
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Abbenseth J, Delony D, Neben MC, Würtele C, de Bruin B, Schneider S. Interconversion of Phosphinyl Radical and Phosphinidene Complexes by Proton Coupled Electron Transfer. Angew Chem Int Ed Engl 2019; 58:6338-6341. [PMID: 30840783 PMCID: PMC6519162 DOI: 10.1002/anie.201901470] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Indexed: 12/04/2022]
Abstract
The isolable complex [Os(PHMes*)H(PNP)] (Mes*=2,4,6-t Bu3 C6 H3 ; PNP=N{CHCHPt Bu2 }2 ) exhibits high phosphinyl radical character. This compound offers access to the phosphinidene complex [Os(PMes*)H(PNP)] by P-H proton coupled electron transfer (PCET). The P-H bond dissociation energy (BDE) was determined by isothermal titration calorimetry and supporting DFT computations. The phosphinidene product exhibits electrophilic reactivity as demonstrated by intramolecular C-H activation.
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Affiliation(s)
- Josh Abbenseth
- Georg-August-Universität GöttingenInstitut für Anorganische ChemieTammannstraße 437077GöttingenGermany
| | - Daniel Delony
- Georg-August-Universität GöttingenInstitut für Anorganische ChemieTammannstraße 437077GöttingenGermany
| | - Marc C. Neben
- Georg-August-Universität GöttingenInstitut für Anorganische ChemieTammannstraße 437077GöttingenGermany
| | - Christian Würtele
- Georg-August-Universität GöttingenInstitut für Anorganische ChemieTammannstraße 437077GöttingenGermany
| | - Bas de Bruin
- Van't Hoff Institute for Molecular Sciences (HIMS)University of Amsterdam (UvA)Science Park 9041098XHAmsterdamThe Netherlands
| | - Sven Schneider
- Georg-August-Universität GöttingenInstitut für Anorganische ChemieTammannstraße 437077GöttingenGermany
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12
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Abbenseth J, Delony D, Neben MC, Würtele C, de Bruin B, Schneider S. Interconversion of Phosphinyl Radical and Phosphinidene Complexes by Proton Coupled Electron Transfer. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201901470] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Josh Abbenseth
- Georg-August-Universität GöttingenInstitut für Anorganische Chemie Tammannstraße 4 37077 Göttingen Germany
| | - Daniel Delony
- Georg-August-Universität GöttingenInstitut für Anorganische Chemie Tammannstraße 4 37077 Göttingen Germany
| | - Marc C. Neben
- Georg-August-Universität GöttingenInstitut für Anorganische Chemie Tammannstraße 4 37077 Göttingen Germany
| | - Christian Würtele
- Georg-August-Universität GöttingenInstitut für Anorganische Chemie Tammannstraße 4 37077 Göttingen Germany
| | - Bas de Bruin
- Van't Hoff Institute for Molecular Sciences (HIMS)University of Amsterdam (UvA) Science Park 904 1098 XH Amsterdam The Netherlands
| | - Sven Schneider
- Georg-August-Universität GöttingenInstitut für Anorganische Chemie Tammannstraße 4 37077 Göttingen Germany
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13
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Römelt C, Weyhermüller T, Wieghardt K. Structural characteristics of redox-active pyridine-1,6-diimine complexes: Electronic structures and ligand oxidation levels. Coord Chem Rev 2019. [DOI: 10.1016/j.ccr.2018.09.018] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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14
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Gu NX, Ung G, Peters JC. Catalytic hydrazine disproportionation mediated by a thiolate-bridged VFe complex. Chem Commun (Camb) 2019; 55:5363-5366. [DOI: 10.1039/c9cc00345b] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A heterobimetallic VFe complex is demonstrated to catalyse hydrazine disproportionation with yields of up to 1073 equivalents of NH3 per catalyst, comparable to the highest turnover known for any molecular catalyst.
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Affiliation(s)
- Nina X. Gu
- Division of Chemistry and Chemical Engineering
- California Institute of Technology
- Pasadena
- USA
| | - Gaël Ung
- Department of Chemistry
- University of Connecticut
- Storrs
- USA
| | - Jonas C. Peters
- Division of Chemistry and Chemical Engineering
- California Institute of Technology
- Pasadena
- USA
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15
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Alig L, Fritz M, Schneider S. First-Row Transition Metal (De)Hydrogenation Catalysis Based On Functional Pincer Ligands. Chem Rev 2018; 119:2681-2751. [PMID: 30596420 DOI: 10.1021/acs.chemrev.8b00555] [Citation(s) in RCA: 497] [Impact Index Per Article: 82.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The use of 3d metals in de/hydrogenation catalysis has emerged as a competitive field with respect to "traditional" precious metal catalyzed transformations. The introduction of functional pincer ligands that can store protons and/or electrons as expressed by metal-ligand cooperativity and ligand redox-activity strongly stimulated this development as a conceptual starting point for rational catalyst design. This review aims at providing a comprehensive picture of the utilization of functional pincer ligands in first-row transition metal hydrogenation and dehydrogenation catalysis and related synthetic concepts relying on these such as the hydrogen borrowing methodology. Particular emphasis is put on the implementation and relevance of cooperating and redox-active pincer ligands within the mechanistic scenarios.
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Affiliation(s)
- Lukas Alig
- Universität Göttingen , Institut für Anorganische Chemie , Tammannstrasse 4 , D-37077 Göttingen , Germany
| | - Maximilian Fritz
- Universität Göttingen , Institut für Anorganische Chemie , Tammannstrasse 4 , D-37077 Göttingen , Germany
| | - Sven Schneider
- Universität Göttingen , Institut für Anorganische Chemie , Tammannstrasse 4 , D-37077 Göttingen , Germany
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16
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Chang MC, McNeece AJ, Hill EA, Filatov AS, Anderson JS. Ligand-Based Storage of Protons and Electrons in Dihydrazonopyrrole Complexes of Nickel. Chemistry 2018; 24:8001-8008. [PMID: 29572998 DOI: 10.1002/chem.201800658] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Indexed: 12/24/2022]
Abstract
A newly developed dihydrazonopyrrole ligand and corresponding Ni complexes have been synthesized and thoroughly characterized. Electrochemical studies and chemical reactivity tests show that these complexes can reversibly store both electrons and protons, or equivalently H-atoms, via ligand-based events. The stored H-atom equivalent can be transferred to small molecules such as acetonitrile or oxygen. Furthermore, this series of complexes can adopt a variety of different coordination modes. In addition to one e- reactivity, the two e- electrophilic oxidation of phosphines is also demonstrated. Taken together, these results show that dihydrazonopyrrole complexes represent a geometrically and electronically flexible scaffold for controlling the flow of both electrons and protons.
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Affiliation(s)
- Mu-Chieh Chang
- Department of Chemistry, The University of Chicago, Chicago, 5735 S Ellis Ave, Chicago, IL, 60637, USA
| | - Andrew J McNeece
- Department of Chemistry, The University of Chicago, Chicago, 5735 S Ellis Ave, Chicago, IL, 60637, USA
| | - Ethan A Hill
- Department of Chemistry, The University of Chicago, Chicago, 5735 S Ellis Ave, Chicago, IL, 60637, USA
| | - Alexander S Filatov
- Department of Chemistry, The University of Chicago, Chicago, 5735 S Ellis Ave, Chicago, IL, 60637, USA
| | - John S Anderson
- Department of Chemistry, The University of Chicago, Chicago, 5735 S Ellis Ave, Chicago, IL, 60637, USA
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Luconi L, Rossin A, Tuci G, Gafurov Z, Lyubov DM, Trifonov AA, Cicchi S, Ba H, Pham‐Huu C, Yakhvarov D, Giambastiani G. Benzoimidazole‐Pyridylamido Zirconium and Hafnium Alkyl Complexes as Homogeneous Catalysts for Tandem Carbon Dioxide Hydrosilylation to Methane. ChemCatChem 2018. [DOI: 10.1002/cctc.201800077] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Lapo Luconi
- Institute of Chemistry of OrganoMetallic Compounds, ICCOM-CNR Via Madonna del Piano, 10 50019 Sesto Fiorentino (Florence) Italy
| | - Andrea Rossin
- Institute of Chemistry of OrganoMetallic Compounds, ICCOM-CNR Via Madonna del Piano, 10 50019 Sesto Fiorentino (Florence) Italy
| | - Giulia Tuci
- Institute of Chemistry of OrganoMetallic Compounds, ICCOM-CNR Via Madonna del Piano, 10 50019 Sesto Fiorentino (Florence) Italy
- Department of Chemistry “Ugo Schiff”University of Florence 50019 Sesto Fiorentino Italy
| | - Zufar Gafurov
- A.E.Arbuzov Institute of Organic and Physical ChemistryRussian Academy of Sciences Arbuzov str. 8 420088 Kazan Russian Federation
- Kazan Federal University 420008 Kazan Russian Federation
| | - Dmitrii M. Lyubov
- G. A. Razuvaev Institute of Organometallic Chemistry of theRussian Academy of Sciences Tropinina 49, GSP-445 603950 Nizhny Novgorod Russia
| | - Alexander A. Trifonov
- G. A. Razuvaev Institute of Organometallic Chemistry of theRussian Academy of Sciences Tropinina 49, GSP-445 603950 Nizhny Novgorod Russia
| | - Stefano Cicchi
- Department of Chemistry “Ugo Schiff”University of Florence 50019 Sesto Fiorentino Italy
| | - Housseinou Ba
- Institut de Chimie et Procédés pour l'Energie, l'Environnement et la Santé (ICPEES-CNRS)UMR 7515 CNRS-University of Strasbourg (UdS) France
| | - Cuong Pham‐Huu
- Institut de Chimie et Procédés pour l'Energie, l'Environnement et la Santé (ICPEES-CNRS)UMR 7515 CNRS-University of Strasbourg (UdS) France
| | - Dmitry Yakhvarov
- A.E.Arbuzov Institute of Organic and Physical ChemistryRussian Academy of Sciences Arbuzov str. 8 420088 Kazan Russian Federation
- Kazan Federal University 420008 Kazan Russian Federation
| | - Giuliano Giambastiani
- Institute of Chemistry of OrganoMetallic Compounds, ICCOM-CNR Via Madonna del Piano, 10 50019 Sesto Fiorentino (Florence) Italy
- Kazan Federal University 420008 Kazan Russian Federation
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18
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Zheng Y, Zheng W, Wang J, Chang H, Zhu D. Computational Study on N-N Homolytic Bond Dissociation Enthalpies of Hydrazine Derivatives. J Phys Chem A 2018; 122:2764-2780. [PMID: 29470086 DOI: 10.1021/acs.jpca.7b12094] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The hydrazine derivatives have been regarded as the important building blocks in organic chemistry for the synthesis of organic N-containing compounds. It is important to understand the structure-activity relationship of the thermodynamics of N-N bonds, in particular, their strength as measured by using the homolytic bond dissociation enthalpies (BDEs). We calculated the N-N BDEs of 13 organonitrogen compounds by eight composite high-level ab initio methods including G3, G3B3, G4, G4MP2, CBS-QB3, ROCBS-QB3, CBS-Q, and CBS-APNO. Then 25 density functional theory (DFT) methods were selected for calculating the N-N BDEs of 58 organonitrogen compounds. The M05-2X method can provide the most accurate results with the smallest root-mean-square error (RMSE) of 8.9 kJ/mol. Subsequently, the N-N BDE predictions of different hydrazine derivatives including cycloalkylhydrazines, N-heterocyclic hydrazines, arylhydrazines, and hydrazides as well as the substituent effects were investigated in detail by using the M05-2X method. In addition, the analysis including the natural bond orbital (NBO) as well as the energies of frontier orbitals were performed in order to further understand the essence of the N-N BDE change patterns.
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Affiliation(s)
- Yuanyuan Zheng
- College of Chemistry and Chemical Engineering , Shanghai University of Engineering Science , Shanghai 201620 , China
| | - Wenrui Zheng
- College of Chemistry and Chemical Engineering , Shanghai University of Engineering Science , Shanghai 201620 , China
| | - Jiaoyang Wang
- College of Chemistry and Chemical Engineering , Shanghai University of Engineering Science , Shanghai 201620 , China
| | - Huifang Chang
- College of Chemistry and Chemical Engineering , Shanghai University of Engineering Science , Shanghai 201620 , China
| | - Danfeng Zhu
- College of Chemistry and Chemical Engineering , Shanghai University of Engineering Science , Shanghai 201620 , China
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19
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Bezdek MJ, Chirik PJ. Interconversion of Molybdenum Imido and Amido Complexes by Proton-Coupled Electron Transfer. Angew Chem Int Ed Engl 2018; 57:2224-2228. [PMID: 29319929 DOI: 10.1002/anie.201708406] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 12/16/2017] [Indexed: 11/07/2022]
Abstract
Interconversion of the molybdenum amido [(Ph Tpy)(PPh2 Me)2 Mo(NHtBuAr)][BArF24 ] (Ph Tpy=4'-Ph-2,2',6',2"-terpyridine; tBuAr=4-tert-butyl-C6 H4 ; ArF24 =(C6 H3 -3,5-(CF3 )2 )4 ) and imido [(Ph Tpy)(PPh2 Me)2 Mo(NtBuAr)][BArF24 ] complexes has been accomplished by proton-coupled electron transfer. The 2,4,6-tri-tert-butylphenoxyl radical was used as an oxidant and the non-classical ammine complex [(Ph Tpy)(PPh2 Me)2 Mo(NH3 )][BArF24 ] as the reductant. The N-H bond dissociation free energy (BDFE) of the amido N-H bond formed and cleaved in the sequence was experimentally bracketed between 45.8 and 52.3 kcal mol-1 , in agreement with a DFT-computed value of 48 kcal mol-1 . The N-H BDFE in combination with electrochemical data eliminate proton transfer as the first step in the N-H bond-forming sequence and favor initial electron transfer or concerted pathways.
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Affiliation(s)
- Máté J Bezdek
- Department of Chemistry, Princeton University, Frick Laboratory 292, Princeton, 08544, USA
| | - Paul J Chirik
- Department of Chemistry, Princeton University, Frick Laboratory 292, Princeton, 08544, USA
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20
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Bezdek MJ, Chirik PJ. Interconversion of Molybdenum Imido and Amido Complexes by Proton‐Coupled Electron Transfer. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201708406] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Máté J. Bezdek
- Department of Chemistry Princeton University Frick Laboratory 292 Princeton 08544 USA
| | - Paul J. Chirik
- Department of Chemistry Princeton University Frick Laboratory 292 Princeton 08544 USA
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21
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Determining and Understanding N-H Bond Strengths in Synthetic Nitrogen Fixation Cycles. TOP ORGANOMETAL CHEM 2017. [DOI: 10.1007/3418_2016_8] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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22
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23
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Zumeta I, Mendicute-Fierro C, Bustos I, Huertos MA, Rodríguez-Diéguez A, Seco JM, San Sebastian E, Garralda MA. Irida-β-ketoimines Derived from Hydrazines To Afford Metallapyrazoles or N-N Bond Cleavage: A Missing Metallacycle Disclosed by a Theoretical and Experimental Study. Inorg Chem 2016; 55:10284-10293. [PMID: 27689907 DOI: 10.1021/acs.inorgchem.6b01550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Unprecedented metallapyrazoles [IrH2{Ph2P(o-C6H4)CNNHC(o-C6H4)PPh2}] (3) and [IrHCl{Ph2P(o-C6H4)CNNHC(o-C6H4)PPh2}] (4) were obtained by the reaction of the irida-β-ketoimine [IrHCl{(PPh2(o-C6H4CO))(PPh2(o-C6H4CNNH2))H}] (2) in MeOH heated at reflux in the presence and absence of KOH, respectively. In solution, iridapyrazole 3 undergoes a dynamic process due to prototropic tautomerism with an experimental barrier for the exchange of ΔGcoal⧧ = 53.7 kJ mol-1. DFT calculations agreed with an intrapyrazole proton transfer process assisted by two water molecules (ΔG = 63.1 kJ mol-1). An X-ray diffraction study on 4 indicated electron delocalization in the iridapyrazole ring. The reaction of the irida-β-diketone [IrHCl{(PPh2(o-C6H4CO))2H}] (1) with H2NNRR' in aprotic solvents gave irida-β-ketoimines [IrHCl{(PPh2(o-C6H4CO))(PPh2(o-C6H4CNNRR'))H}] (R = R' = Me (5); R = H, R' = Ph (8)), which can undergo N-N bond cleavage to afford the acyl-amide complex [IrHCl(PPh2(o-C6H4CO))(PPh2(o-C6H4C(O)N(CH3)2))-κP,κO] (6) or [IrHCl(PPh2(o-C6H4CO))(PPh2(o-C6H4CN)-κP)(NH2NHPh-κNH2)] (9) containing o-(diphenylphosphine)benzonitrile and phenylhydrazine, respectively. From a CH2Cl2/CH3OH solution of 9 kept at -18 °C, single crystals of [IrHCl(PPh2(o-C6H4CO))(PPh2(o-C6H4CN)-κP))(HN═NPh-κNH)] (10) containing o-(diphenylphosphine)benzonitrile and phenyldiazene were formed, as shown by X-ray diffraction. The reaction of 1 with methylhydrazine in methanol gave the hydrazine complex [IrCl(PPh2(o-C6H4CO))2(NH2NH(CH3)-κNH2)] (7). Single-crystal X-ray diffraction analysis was performed on 6 and 7.
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Affiliation(s)
- Itziar Zumeta
- Facultad de Química de San Sebastián, Universidad del País Vasco (UPV/EHU) , Apdo. 1072, 20080 San Sebastián, Spain
| | - Claudio Mendicute-Fierro
- Facultad de Química de San Sebastián, Universidad del País Vasco (UPV/EHU) , Apdo. 1072, 20080 San Sebastián, Spain
| | - Itxaso Bustos
- Facultad de Química de San Sebastián, Universidad del País Vasco (UPV/EHU) , Apdo. 1072, 20080 San Sebastián, Spain
| | - Miguel A Huertos
- Facultad de Química de San Sebastián, Universidad del País Vasco (UPV/EHU) , Apdo. 1072, 20080 San Sebastián, Spain.,Ikerbasque, Basque Foundation for Science , 48013 Bilbao, Spain
| | | | - José M Seco
- Facultad de Química de San Sebastián, Universidad del País Vasco (UPV/EHU) , Apdo. 1072, 20080 San Sebastián, Spain
| | - Eider San Sebastian
- Facultad de Química de San Sebastián, Universidad del País Vasco (UPV/EHU) , Apdo. 1072, 20080 San Sebastián, Spain
| | - María A Garralda
- Facultad de Química de San Sebastián, Universidad del País Vasco (UPV/EHU) , Apdo. 1072, 20080 San Sebastián, Spain
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24
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Pappas I, Chirik PJ. Catalytic Proton Coupled Electron Transfer from Metal Hydrides to Titanocene Amides, Hydrazides and Imides: Determination of Thermodynamic Parameters Relevant to Nitrogen Fixation. J Am Chem Soc 2016; 138:13379-13389. [DOI: 10.1021/jacs.6b08009] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Iraklis Pappas
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Paul J. Chirik
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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25
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Sarkar P, Tiwari A, Sarmah A, Bhandary S, Roy RK, Mukherjee C. An elusive vinyl radical isolated as an appended unit in a five-coordinate Co(iii)-bis(iminobenzosemiquinone) complex formed via ligand-centered C-S bond cleavage. Chem Commun (Camb) 2016; 52:10613-6. [PMID: 27439588 DOI: 10.1039/c6cc02751b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Redox-active ligand H4Pra(edt(AP/AP)) experienced C-S bond cleavage during complexation reaction with Co(OAc)2·2H2O in the presence of Et3N in CH3OH in air. Thus, formed complex 1 was composed of two iminobenzosemiquinone radicals in its coordination sphere and an unprecedented stable tethered-vinyl radical. The complex has been characterized by mass, X-ray single crystal, X-band EPR, variable-temperature magnetic moment measurements and DFT based computational study.
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Affiliation(s)
- Prasenjit Sarkar
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
| | - Archana Tiwari
- Department of Physics, School of Physical Sciences, Sikkim University, Gangtok-737102, Sikkim, India
| | - Amrit Sarmah
- Department of Chemistry, Birla Institute of Technology and Science (BITS), Pilani-333031, Rajasthan, India
| | - Subhrajyoti Bhandary
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal - 462 066, Madhya Pradesh, India
| | - Ram Kinkar Roy
- Department of Chemistry, Birla Institute of Technology and Science (BITS), Pilani-333031, Rajasthan, India
| | - Chandan Mukherjee
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
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26
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Chciuk TV, Anderson WR, Flowers RA. Proton-Coupled Electron Transfer in the Reduction of Carbonyls by Samarium Diiodide–Water Complexes. J Am Chem Soc 2016; 138:8738-41. [DOI: 10.1021/jacs.6b05879] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Tesia V. Chciuk
- Department of Chemistry, Lehigh University, 6 E. Packer Avenue, Bethlehem, Pennsylvania 18015, United States
| | - William R. Anderson
- Department of Chemistry, Lehigh University, 6 E. Packer Avenue, Bethlehem, Pennsylvania 18015, United States
| | - Robert A. Flowers
- Department of Chemistry, Lehigh University, 6 E. Packer Avenue, Bethlehem, Pennsylvania 18015, United States
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27
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Miller DC, Tarantino KT, Knowles RR. Proton-Coupled Electron Transfer in Organic Synthesis: Fundamentals, Applications, and Opportunities. Top Curr Chem (Cham) 2016; 374:30. [PMID: 27573270 PMCID: PMC5107260 DOI: 10.1007/s41061-016-0030-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 04/21/2016] [Indexed: 10/21/2022]
Abstract
Proton-coupled electron transfers (PCETs) are unconventional redox processes in which both protons and electrons are exchanged, often in a concerted elementary step. While PCET is now recognized to play a central a role in biological redox catalysis and inorganic energy conversion technologies, its applications in organic synthesis are only beginning to be explored. In this chapter, we aim to highlight the origins, development, and evolution of the PCET processes most relevant to applications in organic synthesis. Particular emphasis is given to the ability of PCET to serve as a non-classical mechanism for homolytic bond activation that is complimentary to more traditional hydrogen atom transfer processes, enabling the direct generation of valuable organic radical intermediates directly from their native functional group precursors under comparatively mild catalytic conditions. The synthetically advantageous features of PCET reactivity are described in detail, along with examples from the literature describing the PCET activation of common organic functional groups.
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Affiliation(s)
- David C Miller
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Kyle T Tarantino
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Robert R Knowles
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA.
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28
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Nguyen LQ, Knowles RR. Catalytic C–N Bond-Forming Reactions Enabled by Proton-Coupled Electron Transfer Activation of Amide N–H Bonds. ACS Catal 2016. [DOI: 10.1021/acscatal.6b00486] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Lucas Q. Nguyen
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Robert R. Knowles
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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29
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Bezdek MJ, Chirik PJ. Thermodynamics of N–H bond formation in bis(phosphine) molybdenum(ii) diazenides and the influence of the trans ligand. Dalton Trans 2016; 45:15922-15930. [PMID: 27378665 DOI: 10.1039/c6dt01932c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dinitrogen-derived molybdenum alkyldiazenides and alkylhydrazides were synthesized with various trans ligands. The thermodynamics of N–H bond formation were studied both experimentally and computationally.
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30
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Yamagishi H, Nabeya S, Ikariya T, Kuwata S. Protic Ruthenium Tris(pyrazol-3-ylmethyl)amine Complexes Featuring a Hydrogen-Bonding Network in the Second Coordination Sphere. Inorg Chem 2015; 54:11584-6. [DOI: 10.1021/acs.inorgchem.5b02044] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Hiroaki Yamagishi
- Department of Applied
Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku,
Tokyo 152-8552, Japan
| | - Shohei Nabeya
- Department of Applied
Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku,
Tokyo 152-8552, Japan
| | - Takao Ikariya
- Department of Applied
Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku,
Tokyo 152-8552, Japan
| | - Shigeki Kuwata
- Department of Applied
Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku,
Tokyo 152-8552, Japan
- PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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31
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Chciuk TV, Flowers RA. Proton-Coupled Electron Transfer in the Reduction of Arenes by SmI2–Water Complexes. J Am Chem Soc 2015; 137:11526-31. [DOI: 10.1021/jacs.5b07518] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Tesia V. Chciuk
- Department of Chemistry, Lehigh University, 6 E. Packer
Ave. Bethlehem, Pennsylvania 18015, United States
| | - Robert A. Flowers
- Department of Chemistry, Lehigh University, 6 E. Packer
Ave. Bethlehem, Pennsylvania 18015, United States
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32
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Lindley BM, Wolczanski PT, Cundari TR, Lobkovsky EB. First-Row Transition Metal and Lithium Pyridine-ene-amide Complexes Exhibiting N- and C-Isomers and Ligand-Based Activation of Benzylic C–H Bonds. Organometallics 2015. [DOI: 10.1021/acs.organomet.5b00385] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Brian M. Lindley
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Peter T. Wolczanski
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Thomas R. Cundari
- Department of Chemistry, Center for Advanced
Scientific Computing and Modeling (CASCaM), University of North Texas, Box 305070, Denton, Texas 76203-5070, United States
| | - Emil B. Lobkovsky
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
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33
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Fang H, Jing H, Ge H, Brothers PJ, Fu X, Ye S. The Mechanism of E–H (E = N, O) Bond Activation by a Germanium Corrole Complex: A Combined Experimental and Computational Study. J Am Chem Soc 2015; 137:7122-7. [DOI: 10.1021/jacs.5b01121] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Huayi Fang
- Beijing
National Laboratory for Molecular Sciences, College of Chemistry and
Molecular Engineering, Peking University, Beijing 100871, China
| | - Huize Jing
- Beijing
National Laboratory for Molecular Sciences, College of Chemistry and
Molecular Engineering, Peking University, Beijing 100871, China
| | - Haonan Ge
- Beijing
National Laboratory for Molecular Sciences, College of Chemistry and
Molecular Engineering, Peking University, Beijing 100871, China
| | - Penelope J. Brothers
- School
of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1042, New Zealand
| | - Xuefeng Fu
- Beijing
National Laboratory for Molecular Sciences, College of Chemistry and
Molecular Engineering, Peking University, Beijing 100871, China
| | - Shengfa Ye
- Max-Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, D-45470 Mülheim an der Ruhr, Germany
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34
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Tarantino KT, Miller DC, Callon TA, Knowles RR. Bond-weakening catalysis: conjugate aminations enabled by the soft homolysis of strong N-H bonds. J Am Chem Soc 2015; 137:6440-3. [PMID: 25945955 PMCID: PMC4657442 DOI: 10.1021/jacs.5b03428] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ability of redox-active metal centers to weaken the bonds in associated ligands is well precedented, but has rarely been utilized as a mechanism of substrate activation in catalysis. Here we describe a catalytic bond-weakening protocol for conjugate amination wherein the strong N-H bonds in N-aryl amides (N-H bond dissociation free energies ∼100 kcal/mol) are destabilized by ∼33 kcal/mol upon by coordination to a reducing titanocene complex, enabling their abstraction by the weak H-atom acceptor TEMPO through a proton-coupled electron transfer process. Significantly, this soft homolysis mechanism provides a method to generate closed-shell, metalated nucleophiles under neutral conditions in the absence of a Brønsted base.
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Affiliation(s)
- Kyle T. Tarantino
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - David C. Miller
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Ted A. Callon
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Robert R. Knowles
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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35
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Rivada-Wheelaghan O, Dauth A, Leitus G, Diskin-Posner Y, Milstein D. Synthesis and Reactivity of Iron Complexes with a New Pyrazine-Based Pincer Ligand, and Application in Catalytic Low-Pressure Hydrogenation of Carbon Dioxide. Inorg Chem 2015; 54:4526-38. [DOI: 10.1021/acs.inorgchem.5b00366] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Orestes Rivada-Wheelaghan
- Department of Organic
Chemistry and ‡Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Alexander Dauth
- Department of Organic
Chemistry and ‡Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Gregory Leitus
- Department of Organic
Chemistry and ‡Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yael Diskin-Posner
- Department of Organic
Chemistry and ‡Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - David Milstein
- Department of Organic
Chemistry and ‡Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
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36
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Pappas I, Chirik PJ. Ammonia synthesis by hydrogenolysis of titanium-nitrogen bonds using proton coupled electron transfer. J Am Chem Soc 2015; 137:3498-501. [PMID: 25719966 DOI: 10.1021/jacs.5b01047] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The catalytic hydrogenolysis of the titanium-amide bond in (η(5)-C5Me4SiMe3)2Ti(Cl)NH2 to yield free ammonia is described. The rhodium hydride, (η(5)-C5Me5)(py-Ph)RhH (py-Ph = 2-phenylpyridine), serves as the catalyst and promotes N-H bond formation via hydrogen atom transfer. The N-H bond dissociation free energies of ammonia ligands have also been determined for titanocene and zirconocene complexes and reveal a stark dependence on metal identity and oxidation state. In all cases, the N-H BDFEs of coordinated NH3 decreases by >40 kcal/mol from the value in the free gas phase molecule.
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Affiliation(s)
- Iraklis Pappas
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Paul J Chirik
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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37
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Kim JE, Carroll PJ, Schelter EJ. Bidentate nitroxide ligands stable toward oxidative redox cycling and their complexes with cerium and lanthanum. Chem Commun (Camb) 2015; 51:15047-50. [DOI: 10.1039/c5cc06052d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A redox non-innocent bidentate nitroxide ligand stabilizes a tetravalent cerium cation and subsequently an electron–hole upon the oxidation on the electrochemical time scale.
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Affiliation(s)
- Jee Eon Kim
- P. Roy and Diana T. Vagelos Laboratories
- Department of Chemistry
- University of Pennsylvania
- Philadelphia
- USA
| | - Patrick J. Carroll
- P. Roy and Diana T. Vagelos Laboratories
- Department of Chemistry
- University of Pennsylvania
- Philadelphia
- USA
| | - Eric J. Schelter
- P. Roy and Diana T. Vagelos Laboratories
- Department of Chemistry
- University of Pennsylvania
- Philadelphia
- USA
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38
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Schnoor AC, Gradert C, Schleupner M, Krahmer J, Tuczek F. Molybdenum Bis(Dinitrogen) Complexes Supported by NP3Ligands containing Propylene Linkages: Symmetry Breaking and Geometrical Isomerism. Z Anorg Allg Chem 2014. [DOI: 10.1002/zaac.201400461] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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