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Titova YY. Dynamic EPR Studies of the Formation of Catalytically Active Centres in Multicomponent Hydrogenation Systems. Catalysts 2023. [DOI: 10.3390/catal13040653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
Abstract
The formation of catalytically active nano-sized cobalt-containing structures in multicomponent hydrogenation systems based on Co(acac)2 complex and various cocatalysts, namely, AlEt3, AlEt2(OEt), Li-n-Bu, and (PhCH2)MgCl, has been studied for the first time in detail using dynamic EPR spectroscopy. It is shown that after mixing the initial components, paramagnetic structures are formed, which include a fragment containing Co(0) with the electronic configuration 3d9, as well as a fragment bearing an aluminium, lithium, or magnesium atom, depending on the nature of the used cocatalyst. Such bimetallic paramagnetic sites are stabilized by acetylacetonate ligands. In addition, the paramagnetic complex contains the arene molecule(s), and the cobalt atom is bonded with the atom of the corresponding non-transition through the alkyl group of the co-catalyst, in particular through the carbon atom in the α-position with respect to the atom of the non-transition element. Due to the high reactivity of the described intermediates, they, under the conditions of hydrogenation catalysis, are transformed into nano-sized cobalt-containing structures that act as carriers of the catalytically active sites. Furthermore, because of the high reactivity and paramagnetism, such intermediates can be detected only by the EPR technique. The paper describes the whole experimental way of interpreting the EPR signals corresponding to the intermediates, precursors of catalytically active structures. In addition, a possible mathematical model based on the obtained experimental EPR data is presented.
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Dasgupta A, van Ingen Y, Guerzoni MG, Farshadfar K, Rawson JM, Richards E, Ariafard A, Melen RL. Lewis Acid Assisted Brønsted Acid Catalysed Decarbonylation of Isocyanates: A Combined DFT and Experimental Study. Chemistry 2022; 28:e202201422. [PMID: 35560742 PMCID: PMC9541586 DOI: 10.1002/chem.202201422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Indexed: 12/16/2022]
Abstract
An efficient and mild reaction protocol for the decarbonylation of isocyanates has been developed using catalytic amounts of Lewis acidic boranes. The electronic nature (electron withdrawing, electron neutral, and electron donating) and the position of the substituents (ortho/meta/para) bound to isocyanate controls the chain length and composition of the products formed in the reaction. Detailed DFT studies were undertaken to account for the formation of the mono/di‐carboxamidation products and benzoxazolone compounds.
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Affiliation(s)
- Ayan Dasgupta
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University main Building, Park Place, Cardiff, CF10 3AT, Cymru/Wales, United Kingdom
| | - Yara van Ingen
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University main Building, Park Place, Cardiff, CF10 3AT, Cymru/Wales, United Kingdom
| | - Michael G Guerzoni
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University main Building, Park Place, Cardiff, CF10 3AT, Cymru/Wales, United Kingdom
| | - Kaveh Farshadfar
- Department of Chemistry, Islamic Azad University, Central TehranBranch, Poonak, Tehran, 1469669191, Iran
| | - Jeremy M Rawson
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Ave., Windsor, ON N9B 3P4, Canada
| | - Emma Richards
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University main Building, Park Place, Cardiff, CF10 3AT, Cymru/Wales, United Kingdom
| | - Alireza Ariafard
- School of Natural Sciences-Chemistry, University of Tasmania, Private Bag 75, Hobart, Tasmania, 7001, Australia
| | - Rebecca L Melen
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University main Building, Park Place, Cardiff, CF10 3AT, Cymru/Wales, United Kingdom
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Hoffmann KF, Battke D, Golz P, Rupf SM, Malischewski M, Riedel S. The Tris(pentafluorophenyl)methylium Cation: Isolation and Reactivity. Angew Chem Int Ed Engl 2022; 61:e202203777. [PMID: 35416383 PMCID: PMC9401592 DOI: 10.1002/anie.202203777] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Indexed: 11/09/2022]
Abstract
Herein, we present two different routes for the synthesis of the perfluorinated trityl cation, which allowed the handling of the free, uncoordinated species in organic solvents for the first time. The usage of the weakly coordinating anion [Al(OTeF5)4]− and its derivatives allows the characterization of this species by NMR spectroscopy and most importantly by single‐crystal X‐ray diffraction. The high hydride ion affinity of the cation is shown by hydrogen abstraction from isobutane. Furthermore, cyclic voltammetry reveals its oxidative potential which is supported by the reaction with tris(4‐bromophenyl)amine, giving rise to the formation of the ammoniumyl radical cation, also known as “magic blue”.
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Affiliation(s)
- Kurt F. Hoffmann
- Fachbereich für Biologie, Chemie, Pharmazie Institut für Chemie und Biochemie—Anorganische Chemie Fabeckstraße 34/36 14195 Berlin Germany
| | - David Battke
- Fachbereich für Biologie, Chemie, Pharmazie Institut für Chemie und Biochemie—Anorganische Chemie Fabeckstraße 34/36 14195 Berlin Germany
| | - Paul Golz
- Fachbereich für Biologie, Chemie, Pharmazie Institut für Chemie und Biochemie—Anorganische Chemie Fabeckstraße 34/36 14195 Berlin Germany
| | - Susanne M. Rupf
- Fachbereich für Biologie, Chemie, Pharmazie Institut für Chemie und Biochemie—Anorganische Chemie Fabeckstraße 34/36 14195 Berlin Germany
| | - Moritz Malischewski
- Fachbereich für Biologie, Chemie, Pharmazie Institut für Chemie und Biochemie—Anorganische Chemie Fabeckstraße 34/36 14195 Berlin Germany
| | - Sebastian Riedel
- Fachbereich für Biologie, Chemie, Pharmazie Institut für Chemie und Biochemie—Anorganische Chemie Fabeckstraße 34/36 14195 Berlin Germany
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Hoffmann KF, Battke D, Golz P, Rupf SM, Malischewski M, Riedel S. Das Tris(pentafluorophenyl)methylium‐Kation: Isolation und Reaktivität. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202203777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Kurt F. Hoffmann
- Fachbereich für Biologie, Chemie, Pharmazie Institut für Chemie und Biochemie—Anorganische Chemie Fabeckstraße 34/36 14195 Berlin Deutschland
| | - David Battke
- Fachbereich für Biologie, Chemie, Pharmazie Institut für Chemie und Biochemie—Anorganische Chemie Fabeckstraße 34/36 14195 Berlin Deutschland
| | - Paul Golz
- Fachbereich für Biologie, Chemie, Pharmazie Institut für Chemie und Biochemie—Anorganische Chemie Fabeckstraße 34/36 14195 Berlin Deutschland
| | - Susanne M. Rupf
- Fachbereich für Biologie, Chemie, Pharmazie Institut für Chemie und Biochemie—Anorganische Chemie Fabeckstraße 34/36 14195 Berlin Deutschland
| | - Moritz Malischewski
- Fachbereich für Biologie, Chemie, Pharmazie Institut für Chemie und Biochemie—Anorganische Chemie Fabeckstraße 34/36 14195 Berlin Deutschland
| | - Sebastian Riedel
- Fachbereich für Biologie, Chemie, Pharmazie Institut für Chemie und Biochemie—Anorganische Chemie Fabeckstraße 34/36 14195 Berlin Deutschland
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Böttcher T, Schmidlin NMC, Radtke V, Schmidt A, Lökov M, Leito I. Electronic Modification of a Sterically Demanding Anionic Pyridine Ligand. Z Anorg Allg Chem 2022. [DOI: 10.1002/zaac.202200136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Tobias Böttcher
- Universität Freiburg Institut für Anorganische und Analytische Chemie Albertstr. 21 79104 Freiburg i.Br. GERMANY
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Li S, Hu C, Cui X, Zhang J, Liu LL, Wu L. Site‐Fixed Hydroboration of Terminal and Internal Alkenes using BX
3
/
i
Pr
2
NEt**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202111978] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Sida Li
- State Key Laboratory for Oxo Synthesis and Selective Oxidation Suzhou Research Institute of LICP Lanzhou Institute of Chemical Physics (LICP) Chinese Academy of Sciences Lanzhou 730000 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Chenyang Hu
- Shenzhen Grubbs Institute and Department of Chemistry Southern University of Science and Technology Shenzhen 518055 China
| | - Xin Cui
- State Key Laboratory for Oxo Synthesis and Selective Oxidation Suzhou Research Institute of LICP Lanzhou Institute of Chemical Physics (LICP) Chinese Academy of Sciences Lanzhou 730000 China
| | - Jiong Zhang
- State Key Laboratory for Oxo Synthesis and Selective Oxidation Suzhou Research Institute of LICP Lanzhou Institute of Chemical Physics (LICP) Chinese Academy of Sciences Lanzhou 730000 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Liu Leo Liu
- Shenzhen Grubbs Institute and Department of Chemistry Southern University of Science and Technology Shenzhen 518055 China
| | - Lipeng Wu
- State Key Laboratory for Oxo Synthesis and Selective Oxidation Suzhou Research Institute of LICP Lanzhou Institute of Chemical Physics (LICP) Chinese Academy of Sciences Lanzhou 730000 China
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Li S, Hu C, Cui X, Zhang J, Liu LL, Wu L. Site-Fixed Hydroboration of Terminal and Internal Alkenes using BX 3 / i Pr 2 NEt*. Angew Chem Int Ed Engl 2021; 60:26238-26245. [PMID: 34536251 DOI: 10.1002/anie.202111978] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Indexed: 12/27/2022]
Abstract
An unprecedented and general hydroboration of alkenes with BX3 (X=Br, Cl) as the boration reagent in the presence of i Pr2 NEt is reported. The addition of i Pr2 NEt not only suppresses alkene polymerization and haloboration side reactions but also provides an "H" source for hydroboration. More importantly, the site-fixed installation of a boryl group at the original position of the internal double bond is readily achieved in contrast to conventional transition-metal-catalyzed hydroboration processes. Further application to the synthesis of 1,n-diborylalkanes (n=3-10) is also demonstrated. Preliminary mechanistic studies reveal a major reaction pathway that involves radical species and operates through a frustrated Lewis pair type single-electron-transfer mechanism.
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Affiliation(s)
- Sida Li
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Suzhou Research Institute of LICP, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences, Lanzhou, 730000, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chenyang Hu
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xin Cui
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Suzhou Research Institute of LICP, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Jiong Zhang
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Suzhou Research Institute of LICP, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences, Lanzhou, 730000, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Liu Leo Liu
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Lipeng Wu
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Suzhou Research Institute of LICP, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences, Lanzhou, 730000, China
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