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Kótai B, Laczkó G, Hamza A, Pápai I. Stereocontrol via Propeller Chirality in FLP-Catalyzed Asymmetric Hydrogenation. Chemistry 2024; 30:e202400241. [PMID: 38294415 DOI: 10.1002/chem.202400241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 01/31/2024] [Accepted: 01/31/2024] [Indexed: 02/01/2024]
Abstract
Utilization of chiral frustrated Lewis pairs as catalysts in enantioselective hydrogenation of unsaturated molecules represents a promising approach in asymmetric synthesis. In our effort to improve our current understanding of the factors governing the stereoselectivity in these catalytic processes, herein we examined the mechanism of direct hydrogenation of aromatic enamines catalyzed by a binaphthyl-based chiral amino-borane. Our computational analysis reveals that only one particular conformer of the key borohydride reaction intermediate can be regarded as a reactive form of this species. This borohydride conformer has a well-defined chiral propeller shape, which induces facial selectivity in the hydride transfer to pro-chiral iminium intermediates. The propeller chirality of the reactive borohydride conformer is generated by the axially chiral binaphthyl scaffold of the amino-borane catalyst through stabilizing π-π stacking interactions. This new computational insight can be readily used to interpret the high degree of stereoinduction observed for these reactions. We expect that the concept of chirality relay could be further exploited in catalyst design endeavors.
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Affiliation(s)
- B Kótai
- Institute of Organic Chemistry, Research Centre for Natural Sciences, H-1117, Budapest, Magyar tudósok körútja 2
- Hevesy György Ph.D. School of Chemistry, Eötvös Loránd University, P.O. Box 32, H-1518, Budapest, Hungary
| | - G Laczkó
- Institute of Organic Chemistry, Research Centre for Natural Sciences, H-1117, Budapest, Magyar tudósok körútja 2
- Hevesy György Ph.D. School of Chemistry, Eötvös Loránd University, P.O. Box 32, H-1518, Budapest, Hungary
| | - A Hamza
- Institute of Organic Chemistry, Research Centre for Natural Sciences, H-1117, Budapest, Magyar tudósok körútja 2
| | - I Pápai
- Institute of Organic Chemistry, Research Centre for Natural Sciences, H-1117, Budapest, Magyar tudósok körútja 2
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2
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Yang Z, Huang T, Li M, Wang X, Zhou X, Yang S, Gao Q, Cai X, Liu Y, Fang Y, Wang Y, Zhang S, Zhang S. Unveiling the Synergistic Role of Frustrated Lewis Pairs in Carbon-Encapsulated Ni/NiO x Photothermal Cocatalyst for Enhanced Photocatalytic Hydrogen Production. Adv Mater 2024:e2313513. [PMID: 38461147 DOI: 10.1002/adma.202313513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 03/03/2024] [Indexed: 03/11/2024]
Abstract
The development of high-density and closely spaced frustrated Lewis pairs (FLPs) is crucial for enhancing catalyst activity and accelerating reaction rates. However, constructing efficient FLPs by breaking classical Lewis bonds poses a significant challenge. Here, this work has made a pivotal discovery regarding the Jahn-Teller effect during the formation of grain boundaries in carbon-encapsulated Ni/NiOx (Ni/NiOx @C). This effect facilitates the formation of high-density O (VO ) and Ni (VNi ) vacancy sites with different charge polarities, specifically FLP-VO -C basic sites and FLP-VNi -C acidic sites. The synergistic interaction between FLP-VO -C and FLP-VNi -C sites not only reduces energy barriers for water adsorption and splitting, but also induces a strong photothermal effect. This mutually reinforcing effect contributes to the exceptional performance of Ni/NiOx @C as a cocatalyst in photothermal-assisted photocatalytic hydrogen production. Notably, the Ni/NiOx @C/g-C3 N4 (NOCC) composite photocatalyst exhibits remarkable hydrogen production activity with a rate of 10.7 mmol g-1 h-1 , surpassing that of the Pt cocatalyst by 1.76 times. Moreover, the NOCC achieves an impressive apparent quantum yield of 40.78% at a wavelength of 380 nm. This work paves the way for designing novel defect-state multiphase cocatalysts with high-density and adjacent FLP sites, which hold promise for enhancing various catalytic reactions.
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Affiliation(s)
- Zhi Yang
- Guangdong Laboratory for Lingnan Modern Agriculture, Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, Guangzhou, Guangdong, 510643, P. R. China
| | - Taiyu Huang
- Guangdong Laboratory for Lingnan Modern Agriculture, Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, Guangzhou, Guangdong, 510643, P. R. China
| | - Meng Li
- Institute for Sustainable Transformation, School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, Guangdong, 510006, P. R. China
- Guangdong Laboratory of Chemistry and Fine Chemical Industry Jieyang Center, Jieyang, Guangdong, 515200, China
| | - Xudong Wang
- SMOE Key Laboratory of Bioinorganic and Synthetic Chemistry, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-sen University, Guangzhou, Guangdong, 510275, China
| | - Xiaosong Zhou
- School of Chemistry and Chemical Engineering, Key Laboratory of Clean Energy Materials Chemistry of Guangdong Higher Education Institutes, Lingnan Normal University, Zhanjiang, Guangdong, 524048, P. R. China
| | - Siyuan Yang
- Guangdong Laboratory for Lingnan Modern Agriculture, Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, Guangzhou, Guangdong, 510643, P. R. China
| | - Qiongzhi Gao
- Guangdong Laboratory for Lingnan Modern Agriculture, Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, Guangzhou, Guangdong, 510643, P. R. China
| | - Xin Cai
- Guangdong Laboratory for Lingnan Modern Agriculture, Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, Guangzhou, Guangdong, 510643, P. R. China
| | - Yingju Liu
- Guangdong Laboratory for Lingnan Modern Agriculture, Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, Guangzhou, Guangdong, 510643, P. R. China
| | - Yueping Fang
- Guangdong Laboratory for Lingnan Modern Agriculture, Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, Guangzhou, Guangdong, 510643, P. R. China
| | - Yu Wang
- Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China
| | - Shanqing Zhang
- Institute for Sustainable Transformation, School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, Guangdong, 510006, P. R. China
- Centre for Clean Environment and Energy and School of Environment and Science, Gold Coast Campus, Griffith University, Queensland, 4222, Australia
| | - Shengsen Zhang
- Guangdong Laboratory for Lingnan Modern Agriculture, Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, Guangzhou, Guangdong, 510643, P. R. China
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3
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Rajendran NM, Lu Q, Bouffard J. A Facile Preparation of N-Heterocyclic Olefins: Ring-Opening Polymerization of β-Butyrolactone and Frustrated Lewis Pair Reactivity. Chemistry 2024; 30:e202303358. [PMID: 38109087 DOI: 10.1002/chem.202303358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Indexed: 12/19/2023]
Abstract
A direct synthesis of N-heterocyclic olefins (NHOs) and their mesoionic congeners (mNHOs) from N-heterocyclic carbenes and N-aziridinylimines is reported. The reaction provided diverse functionalized (m)NHOs and π-extended analogues. The prepared NHOs initiated the ring-opening polymerization of β-butyrolactone, and insertion of aldehyde and nitrile into an NHO-B(C6 F5 )3 adduct was demonstrated.
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Affiliation(s)
| | - Qi Lu
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul, 03760, Korea
| | - Jean Bouffard
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul, 03760, Korea
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4
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Yazdanpanah M, Fereidooni M, Márquez V, Paz CV, Saelee T, Salazar Villanueva M, Rittiruam M, Khajondetchairit P, Praserthdam S, Praserthdam P. The Underlying Catalytic Role of Oxygen Vacancies in Fatty Acid Methyl Esters Ketonization over TiO x Catalysts. ChemSusChem 2024; 17:e202301033. [PMID: 37724580 DOI: 10.1002/cssc.202301033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/18/2023] [Accepted: 09/18/2023] [Indexed: 09/21/2023]
Abstract
Recently, interest in converting bio-derived fatty acid methyl esters (FAMEs) into added-value products has significantly increased. The selectivity of ketonization reaction in the conversion of the FAMEs has significantly hampered the efficiency of this process. Herein, this work reports the preparation of catalysts with different levels of oxygen vacancies while the crystal phase remained unchanged. The catalyst with the highest level of oxygen vacancy exhibited the maximum selectivity. The density functional theory (DFT) simulation showed an increase in interatomic distances leading to the formation of frustrated Lewis pairs (FLPs) upon the creation of oxygen vacancies. The surface measurements, type and density of acid sites of the catalysts, showed that the Lewis acid sites enhanced the selectivity for ketone production; while Bronsted acid sites increased the formation of by-products. Moreover, the ketone formation rate was directly proportional to acid density. The findings of this research provide a different approach for catalyst design, based on defects engineering and their effect on the surface activity, which could be used for enhancing the catalytic performance of novel metal oxides.
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Affiliation(s)
- Mohammad Yazdanpanah
- Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Mohammad Fereidooni
- Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Victor Márquez
- Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand
| | - C V Paz
- Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Tinnakorn Saelee
- High-Performance Computing Unit (CECC-HCU), Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Martin Salazar Villanueva
- Facultad de Ingeniería, Benemerita Universidad Autonoma de Puebla, Apartado Postal J-39, CP, 72570, Puebla, Mexico
| | - Meena Rittiruam
- High-Performance Computing Unit (CECC-HCU), Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Patcharaporn Khajondetchairit
- High-Performance Computing Unit (CECC-HCU), Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Supareak Praserthdam
- Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand
- High-Performance Computing Unit (CECC-HCU), Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Piyasan Praserthdam
- Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand
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5
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Guo Y, Lian X, Zhang H, Zhang X, Chen J, Chen C, Lan X, Shao Y. Systematic Assessment of the Catalytic Reactivity of Frustrated Lewis Pairs in C-H Bond Activation. Molecules 2023; 29:24. [PMID: 38202607 PMCID: PMC10780200 DOI: 10.3390/molecules29010024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 12/15/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
Unreactive C-H bond activation is a new horizon for frustrated Lewis pair (FLP) chemistry. This study provides a systematic assessment of the catalytic reactivity of recently reported intra-molecular FLPs on the activation of typical inert C-H bonds, including 1-methylpyrrole, methane, benzyl, propylene, and benzene, in terms of density functional theory (DFT) calculations. The reactivity of FLPs is evaluated according to the calculated reaction thermodynamic and energy barriers of C-H bond activation processes in the framework of concerted C-H activation mechanisms. As for 1-methylpyrrole, 14 types of N-B-based and 15 types of P-B-based FLPs are proposed to be active. Although none of the evaluated FLPs are able to catalyze the C-H activation of methane, benzyl, or propylene, four types of N-B-based FLPs are suggested to be capable of catalyzing the activation of benzene. Moreover, the influence of the strength of Lewis acid (LA) and Lewis base (LB), and the differences between the influences of LA and LB on the catalytic reactivity of FLPs, are also discussed briefly. This systematic assessment of the catalytic activity of FLPs should provide valuable guidelines to aid the development of efficient FLP-based metal-free catalysts for C-H bond activation.
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Affiliation(s)
- Yongjie Guo
- Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds Research and Application, School of Chemistry and Environmental Science, Xiangnan University, Chenzhou 423000, China; (Y.G.); (H.Z.); (J.C.); (C.C.)
| | - Xueqi Lian
- Key Laboratory of Electronic Functional Materials and Devices of Guangdong Province, School of Chemistry and Materials Engineering, Huizhou University, Huizhou 516007, China; (X.L.); (X.Z.)
| | - Hao Zhang
- Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds Research and Application, School of Chemistry and Environmental Science, Xiangnan University, Chenzhou 423000, China; (Y.G.); (H.Z.); (J.C.); (C.C.)
| | - Xueling Zhang
- Key Laboratory of Electronic Functional Materials and Devices of Guangdong Province, School of Chemistry and Materials Engineering, Huizhou University, Huizhou 516007, China; (X.L.); (X.Z.)
| | - Jun Chen
- Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds Research and Application, School of Chemistry and Environmental Science, Xiangnan University, Chenzhou 423000, China; (Y.G.); (H.Z.); (J.C.); (C.C.)
| | - Changzhong Chen
- Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds Research and Application, School of Chemistry and Environmental Science, Xiangnan University, Chenzhou 423000, China; (Y.G.); (H.Z.); (J.C.); (C.C.)
| | - Xiaobing Lan
- Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds Research and Application, School of Chemistry and Environmental Science, Xiangnan University, Chenzhou 423000, China; (Y.G.); (H.Z.); (J.C.); (C.C.)
| | - Youxiang Shao
- Key Laboratory of Electronic Functional Materials and Devices of Guangdong Province, School of Chemistry and Materials Engineering, Huizhou University, Huizhou 516007, China; (X.L.); (X.Z.)
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6
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Frenette BL, Rivard E. Frustrated Lewis Pair Chelation in the p-Block. Chemistry 2023; 29:e202302332. [PMID: 37677126 DOI: 10.1002/chem.202302332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/06/2023] [Accepted: 09/07/2023] [Indexed: 09/09/2023]
Abstract
Frustrated Lewis pairs (FLPs) have been the subject of considerable study since the field's inception. While much of the research into FLPs has centered around small molecule activation for diverse stoichiometric and catalytic transformations, intramolecular FLPs also show promise as chelating ligands. The cooperative action of Lewis basic and acidic moieties enables intramolecular FLPs to stabilize low oxidation state centers and (consequently) reactive molecular fragments through a donor-acceptor approach, making them an attractive ligand class in main group element chemistry. This review outlines the state of FLP chelation to date throughout the p-block, encompassing primarily groups 13-16.
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Affiliation(s)
- Brandon L Frenette
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta, T6G 2G2, Canada
| | - Eric Rivard
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta, T6G 2G2, Canada
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7
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Durin G, Berthet JC, Thuéry P, Nicolas E, Cantat T. Metal-Free Catalytic Hydrogenolysis of Chlorosilanes into Hydrosilanes with "Inverse" Frustrated Lewis Pairs. Chemistry 2023; 29:e202302155. [PMID: 37665089 DOI: 10.1002/chem.202302155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 09/05/2023]
Abstract
The challenging metal-free catalytic hydrogenolysis of silyl chlorides to hydrosilanes is unlocked by using an inverse frustrated Lewis pair (FLP), combining a mild Lewis acid (Cy2 BCl) and a strong phosphazene base (BTPP) in mild conditions (10 bar of H2 , r. t.). In the presence of a stoichiometric amount of the base, the hydrosilanes R3 SiH (R=Me, Et, Ph) are generated in moderate to high yields (up to 95 %) from their chlorinated counterparts. A selective formation of the valuable difunctional monohydride Me2 SiHCl is also obtained from Me2 SiCl2 . A mechanism is proposed based on stoichiometric experiments and DFT calculations; it highlights the critical role of borohydride species generated by the heterolytic splitting of H2 .
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Affiliation(s)
- Gabriel Durin
- Université Paris-Saclay, CEA, CNRS, NIMBE, 91191, Gif-sur-Yvette, France
| | | | - Pierre Thuéry
- Université Paris-Saclay, CEA, CNRS, NIMBE, 91191, Gif-sur-Yvette, France
| | - Emmanuel Nicolas
- Université Paris-Saclay, CEA, CNRS, NIMBE, 91191, Gif-sur-Yvette, France
| | - Thibault Cantat
- Université Paris-Saclay, CEA, CNRS, NIMBE, 91191, Gif-sur-Yvette, France
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8
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Mebs S. In Silico Partial N 2 to NH 3 Conversion with a Light Atom Molecule. Chemphyschem 2023; 24:e202200621. [PMID: 36416275 DOI: 10.1002/cphc.202200621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/20/2022] [Accepted: 11/22/2022] [Indexed: 11/24/2022]
Abstract
N2 can be stepwise converted in silico into one molecule NH3 and a secondary amide with a bond activator molecule consisting only of light main group elements. The proposed N2 -activating pincer-related compound carries a silyl ion (Si(+) ) center as well as three Lewis acidic (-BF2 ) and three Lewis basic (-PMe2 ) sites, providing an efficient binding pocket for gaseous N2 within the framework of intramolecular frustrated Lewis pairs (FLP). In addition, it exhibits supportive secondary P-B and F⋅⋅⋅B contacts, which stabilize the structure. In the PSi(+) -N-N-BP environment the N≡N triple bond is extended from 1.09 Å to remarkable 1.43 Å, resembling a N-N single bond. The strongly activated N-N-fragment is prone to subsequent hydride addition and protonation steps, resulting in the energy efficient transfer of two hydrogen equivalents. The next hydride added causes the release of one molecule NH3 , but leaves the ligand system as poisoned R3 Si(+) -NH2 -PMe2 or R3 Si(+) -NH3 dead-end states behind. The study indicates that approximately tetrahedral constrained SiBP2 -pockets are capable to activate N2 , whereas the acid-rich SiB3 - and SiB2 P-pocktes, as well as the base-rich SiP3 -pockets fail, hinting towards the high relevance of the acid-base proportion and relative orientation. The electronic structure of the N2 -activated state is compared to the corresponding state of a recently published peri-substituted bond activator molecule featuring a PSi(+) -N-N-Si(+) P site (S. Mebs, J. Beckmann, Physical Chemistry Chemical Physics 2022, 24, 20953-20967).
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Affiliation(s)
- Stefan Mebs
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
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9
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Coffinet A, Specklin D, Le Dé Q, Bennaamane S, Muñoz L, Vendier L, Clot E, Mézailles N, Simonneau A. Assessing Combinations of B(C 6 F 5 ) 3 and N 2 -Derived Molybdenum Nitrido Complexes for Heterolytic Bond Activation. Chemistry 2023; 29:e202203774. [PMID: 36805704 DOI: 10.1002/chem.202203774] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 02/10/2023] [Accepted: 02/20/2023] [Indexed: 02/22/2023]
Abstract
Two different dinitrogen-derived molybdenum nitrido complexes varying by their geometry, ligand spheres and oxidations states were shown to engage their N ligand in dative bonding with the strong Lewis acid B(C6 F5 )3 . The stable adducts were assessed for frustrated Lewis pair-type heterolytic E-H bond splitting of hydrosilanes (E=Si) and HB(C6 F5 )2 . Whereas Si-H bond activation was achieved, HB(C6 F5 )2 was shown to substitute B(C6 F5 )3 in a quantitative or equilibrated fashion, depending on the nature of the nitrido complex. No B-H bond splitting was observed. Thermodynamics of these reactions, computed by DFT, are in agreement with the experimental outcomes.
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Affiliation(s)
- Anaïs Coffinet
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, F-31077, Toulouse cedex 4, France
| | - David Specklin
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, F-31077, Toulouse cedex 4, France
| | - Quentin Le Dé
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, F-31077, Toulouse cedex 4, France
| | - Soukaina Bennaamane
- Laboratoire Hétérochimie Fondamentale et Appliquée, Université Paul Sabatier, CNRS, 118 Route de Narbonne, 31062, Toulouse, France
| | - Luna Muñoz
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, F-31077, Toulouse cedex 4, France
| | - Laure Vendier
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, F-31077, Toulouse cedex 4, France
| | - Eric Clot
- ICGM, Univ. Montpellier, CNRS, ENSCM, 34000, Montpellier, France
| | - Nicolas Mézailles
- Laboratoire Hétérochimie Fondamentale et Appliquée, Université Paul Sabatier, CNRS, 118 Route de Narbonne, 31062, Toulouse, France
| | - Antoine Simonneau
- LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, F-31077, Toulouse cedex 4, France
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10
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Wickemeyer L, Trapp PC, Aders N, Neumann B, Stammler HG, Mitzel NW. Reactivity of Oxygen-Bridged Geminal Al/P and Si/P Frustrated Lewis Pairs towards Heterocumulenes. Chemistry 2023; 29:e202203685. [PMID: 36734185 DOI: 10.1002/chem.202203685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 02/02/2023] [Accepted: 02/03/2023] [Indexed: 02/04/2023]
Abstract
The two oxygen-bridged geminal frustrated Lewis pairs (FLP) tBu2 P-O-AlBis2 (Bis=CH(SiMe3 )2 ; 1) and tBu2 P-O-Si(C2 F5 )3 (2) were reacted with the heterocumulenes PhNCO, PhOCN, PhNCS, CS2 and PhNSO as well as SO2 . With isocyanate and cyanate, both 1 and 2, form addition products under formation of five-membered rings. With CS2 , isothiocyanate and sulfinylaniline, only 1 forms stable adducts, whereas 2 shows reactivity towards sulfinylaniline, but the product decomposed after a few minutes. The reaction of 1 with SO2 led to partial cleavage of the P-O-Al and Al-C units, as confirmed by X-ray diffraction studies of a complex aggregate. The reaction of 2 with SO2 affords the 1,2-addition product. All adducts were characterized by means of multinuclear NMR spectroscopy, X-ray crystallography and CHN analyses.
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Affiliation(s)
- Lucas Wickemeyer
- Lehrstuhl für Anorganische Chemie und Strukturchemie and, Centrum für Molekulare Materialen CM2, Fakultät für Chemie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Pia C Trapp
- Lehrstuhl für Anorganische Chemie und Strukturchemie and, Centrum für Molekulare Materialen CM2, Fakultät für Chemie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Niklas Aders
- Lehrstuhl für Anorganische Chemie und Strukturchemie and, Centrum für Molekulare Materialen CM2, Fakultät für Chemie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Beate Neumann
- Lehrstuhl für Anorganische Chemie und Strukturchemie and, Centrum für Molekulare Materialen CM2, Fakultät für Chemie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Hans-Georg Stammler
- Lehrstuhl für Anorganische Chemie und Strukturchemie and, Centrum für Molekulare Materialen CM2, Fakultät für Chemie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Norbert W Mitzel
- Lehrstuhl für Anorganische Chemie und Strukturchemie and, Centrum für Molekulare Materialen CM2, Fakultät für Chemie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany
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11
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Chen T, Mei Y, Liu LL, Zhao Y, Wu Y, Stephan DW. Alkoxyphosphorane/Borane Cooperative Alkylations: A Frustrated Lewis Pair Version of the Mitsunobu Reaction. Chemistry 2023; 29:e202300264. [PMID: 36715454 DOI: 10.1002/chem.202300264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 01/27/2023] [Accepted: 01/30/2023] [Indexed: 01/31/2023]
Abstract
The combination of the alkoxyphosphoranes, Ph2 P(OR)(O2 C6 Cl4 ) and the borane B(C6 F5 )3 generates the zwitterions 3 which act as FLP to effect the alkylation of several nucleophiles affording C-C, C-N, C-H and C-Cl coupling products. A DFT study shows the reaction proceeds via an FLP activation pathway generating an alkoxyphosphonium intermediate which effects the alkylation of the nucleophiles, akin to the Mitsunobu reaction.
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Affiliation(s)
- Ting Chen
- Institute of Drug Discovery Technology, Ningbo University, 315211, Ningbo, Zhejiang, P. R. China
| | - Yanbo Mei
- Department of Chemistry and, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, 518055, Shenzhen, P. R. China
| | - Liu Leo Liu
- Department of Chemistry and, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, 518055, Shenzhen, P. R. China
| | - Yufen Zhao
- Institute of Drug Discovery Technology, Ningbo University, 315211, Ningbo, Zhejiang, P. R. China
| | - Yile Wu
- Institute of Drug Discovery Technology, Ningbo University, 315211, Ningbo, Zhejiang, P. R. China
| | - Douglas W Stephan
- Institute of Drug Discovery Technology, Ningbo University, 315211, Ningbo, Zhejiang, P. R. China.,Department of Chemistry, University of Toronto, 80 St. George St, M5S3H6, Toronto, ON, Canada
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12
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Zhou Y, Chen Y, Luo X, Wang X. Nonoxidative Coupling of Methane to Produce C(2) Hydrocarbons on FLPs of an Albite Surface. Molecules 2023; 28. [PMID: 36770703 DOI: 10.3390/molecules28031037] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/15/2023] [Accepted: 01/16/2023] [Indexed: 01/22/2023] Open
Abstract
The characteristics of active sites on the surface of albite were theoretically analyzed by density functional theory, and the activation of the C-H bond of methane using an albite catalyst and the reaction mechanism of preparing C2 hydrocarbons by nonoxidative coupling were studied. There are two frustrated Lewis pairs (FLPs) on the (001) and (010) surfaces of albite; they can dissociate H2 under mild conditions and show high activity for the activation of methane C-H bonds. CH4 molecules can undergo direct dissociative adsorption on the (010) surface, whereas a 50.07 kJ/mol activation barrier is needed on the (001) surface. The prepared albite catalyst has a double combination function of the (001) and (010) surfaces; these surfaces produce a spillover phenomenon in the process of CH4 activation reactions, where CH3 overflows from the (001) surface with CH3 adsorbed on the (010) surface to achieve nonoxidative high efficiently C-C coupling with an activation energy of 18.51 kJ/mol. At the same time, this spillover phenomenon inhibits deep dehydrogenation, which is conducive to the selectivity of the C2 hydrocarbons. The experimental results confirm that the selectivity of the C2 hydrocarbons is maintained above 99% in the temperature range of 873 K to 1173 K.
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13
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Sorochkina K, Chernichenko K, Zhivonitko VV, Nieger M, Repo T. Water Reduction and Dihydrogen Addition in Aqueous Conditions With ansa-Phosphinoborane. Chemistry 2022; 28:e202201927. [PMID: 35861909 PMCID: PMC9804508 DOI: 10.1002/chem.202201927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Indexed: 01/05/2023]
Abstract
Ortho-phenylene-bridged phosphinoborane (2,6-Cl2 Ph)2 B-C6 H4 -PCy2 1 was synthesized in three steps from commercially available starting materials. 1 reacts with H2 or H2 O under mild conditions to form corresponding zwitterionic phosphonium borates 1-H2 or 1-H2 O. NMR studies revealed both reactions to be remarkably reversible. Thus, when exposed to H2 , 1-H2 O partially converts to 1-H2 even in the presence of multiple equivalents of water in the solution. The addition of parahydrogen to 1 leads to nuclear spin hyperpolarization both in dry and hydrous solvents, confirming the dissociation of 1-H2 O to free 1. These observations were supported by computational studies indicating that the formation of 1-H2 and 1-H2 O from 1 are thermodynamically favored. Unexpectedly, 1-H2 O can release molecular hydrogen to form phosphine oxide 1-O. Kinetic, mechanistic, and computational (DFT) studies were used to elucidate the unique "umpolung" water reduction mechanism.
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Affiliation(s)
- Kristina Sorochkina
- Department of ChemistryUniversity of HelsinkiA. I. Virtasen aukio 100014HelsinkiFinland
| | - Konstantin Chernichenko
- Department of ChemistryUniversity of HelsinkiA. I. Virtasen aukio 100014HelsinkiFinland,Chemical Process Research and Development Janssen PharmaceuticaTurnhoutseweg 302340BeerseBelgium
| | | | - Martin Nieger
- Department of ChemistryUniversity of HelsinkiA. I. Virtasen aukio 100014HelsinkiFinland
| | - Timo Repo
- Department of ChemistryUniversity of HelsinkiA. I. Virtasen aukio 100014HelsinkiFinland
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14
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Thorwart T, Hartmann D, Greb L. Dihydrogen Activation with a Neutral, Intermolecular Silicon(IV)-Amine Frustrated Lewis Pair. Chemistry 2022; 28:e202202273. [PMID: 35861023 DOI: 10.1002/chem.202202273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Indexed: 01/07/2023]
Abstract
The heterolytic cleavage of dihydrogen constitutes the hallmark reaction of frustrated Lewis pairs (FLP). While being well-established for planar Lewis acids, such as boranes or silylium ions, the observation of the primary H2 splitting products with non-planar Lewis acid FLPs remained elusive. In the present work, we report bis(perfluoro-N-phenyl-ortho-amidophenolato)silane and its application in dihydrogen activation to a fully characterized hydridosilicate. The strict design of the Lewis acid, the limited selection of the Lewis base, and the distinct reaction conditions emphasize the narrow tolerance to achieve this fascinating process with a tetrahedral Lewis acid.
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Affiliation(s)
- Thaddäus Thorwart
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Deborah Hartmann
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Lutz Greb
- Department of Chemistry and Biochemistry-Inorganic Chemistry, Freie Universität Berlin, Fabeckstr. 34/36, 14195, Berlin, Germany
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15
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Abstract
Reactions of PAr3 /B(C6 F5 )3 (Ar=o-Tol, Mes, Ph) FLPs with diethyl azodicarboxylate (DEAD) afford the corresponding FLP addition products 1-3 in which P-N and B-O linkages are formed. In contrast, the reaction of BPh3 , PPh3 and DEAD gave product 4 where P-N and N-B linkages were confirmed. In all cases, other binding modes were computed to be both higher in energy and readily distinguishable by 31 P and 11 B NMR parameters. These data illustrate the influence of steric demands and electronic structures on the nature of the products of FLP reactions with DEAD.
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Affiliation(s)
- Dipendu Mandal
- Institute of Drug Discovery TechnologyNingbo University315211ZhejiangP. R. China
| | - Ting Chen
- Institute of Drug Discovery TechnologyNingbo University315211ZhejiangP. R. China
| | - Zheng‐Wang Qu
- Mulliken Center for Theoretical ChemistryClausius Institut für Physikalische und Theoretische ChemieRheinische Friedrich-Wilhelms-Universität BonnBeringstrasse 453115BonnGermany
| | - Stefan Grimme
- Mulliken Center for Theoretical ChemistryClausius Institut für Physikalische und Theoretische ChemieRheinische Friedrich-Wilhelms-Universität BonnBeringstrasse 453115BonnGermany
| | - Douglas W. Stephan
- Institute of Drug Discovery TechnologyNingbo University315211ZhejiangP. R. China,Department of ChemistryUniversity of Toronto80 St. George StM5S3H6TorontoONCanada
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16
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Ferrer M, Alkorta I, Elguero J, Oliva‐Enrich JM. Use of 5,10-Disubstituted Dibenzoazaborines and Dibenzophosphaborines as Cyclic Supports of Frustrated Lewis Pairs for the Capture of CO 2. Chemphyschem 2022; 23:e202200204. [PMID: 35703469 PMCID: PMC9796958 DOI: 10.1002/cphc.202200204] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 06/14/2022] [Indexed: 01/07/2023]
Abstract
The reactivity of 5,10-disubstituted dibenzoazaborines and dibenzophosphaborines towards carbon dioxide was studied at the DFT, M06-2X/def2-TZVP, computational level. The profile of this reaction comprises of three stationary points: the pre-reactive complex and adduct minima and the transition state(TS) linking both minima. Initial results show that dibenzoazaborines derivatives are less suitable to form adducts with CO2 than dibenzophosphaborine systems. The influence of the basicity on the P atom and the acidity on the B center of the dibenzophosphaborine in the reaction with CO2 was also explored. Thus, an equation was developed relating the properties (acidity, basicity and boron hybridization) of the isolated dibenzophosphaborine derivatives with the adduct energy. We found that modulation of the boron acidity allows to obtain more stable adducts than the pre-reactive complexes and isolated monomers.
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Affiliation(s)
- Maxime Ferrer
- Instituto de Química Médica (CSIC)Juan de la Cierva, 328006MadridSpain,PhD Program in Theoretical Chemistry and Computational ModelingDoctoral SchoolUniversidad Autónoma de Madrid28049MadridSpain
| | - Ibon Alkorta
- Instituto de Química Médica (CSIC)Juan de la Cierva, 328006MadridSpain
| | - Jose Elguero
- Instituto de Química Médica (CSIC)Juan de la Cierva, 328006MadridSpain
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17
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He Y, Li C, Chen XB, Shi Z, Feng S. Visible-Light-Responsive UiO-66(Zr) with Defects Efficiently Promoting Photocatalytic CO 2 Reduction. ACS Appl Mater Interfaces 2022; 14:28977-28984. [PMID: 35713698 DOI: 10.1021/acsami.2c06993] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
It is of great importance to understand the relationship between the structure and properties at the atomic level, which provides a solid platform for the design of efficient heterogeneous catalysts. However, it remains a challenge to elucidate the roles of the structure of reaction sites in the catalytic activity of active sites due to the lack of understanding of the structure of specific active site species. Herein, taking the metal-organic framework (MOF) UiO-66(Zr) as a prototype, MOF catalysts with all-solid-state frustrated Lewis pairs (FLPs) Zr3+-OH were synthesized in situ by adding acetic acid (HAc) as a modulator. By introducing missing linkers, UiO-66(Zr) first becomes a visible-light-responsive photocatalyst for CO2 reduction. The in situ Fourier transform infrared (FTIR) spectrum reveals that b-CO32- is the key intermediate for the activation of CO2 molecules through FLPs Zr3+-OH. Moreover, defective UiO-66(Zr) could "self-breath" by surface hydroxyls. This finding not only provides a new avenue for utilizing UV-responsive MOFs by defect engineering but also sheds light on its catalytic activity at the atomic level.
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Affiliation(s)
- Yiqiang He
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Chunguang Li
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Xiao-Bo Chen
- School of Engineering, RMIT University, Carlton, VIC 3053, Australia
| | - Zhan Shi
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Shouhua Feng
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
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18
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Wan Q, Lin S, Guo H. Frustrated Lewis Pairs in Heterogeneous Catalysis: Theoretical Insights. Molecules 2022; 27:molecules27123734. [PMID: 35744860 PMCID: PMC9227528 DOI: 10.3390/molecules27123734] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/06/2022] [Accepted: 06/07/2022] [Indexed: 12/10/2022] Open
Abstract
Frustrated Lewis pair (FLP) catalysts have attracted much recent interest because of their exceptional ability to activate small molecules in homogeneous catalysis. In the past ten years, this unique catalysis concept has been extended to heterogeneous catalysis, with much success. Herein, we review the recent theoretical advances in understanding FLP-based heterogeneous catalysis in several applications, including metal oxides, functionalized surfaces, and two-dimensional materials. A better understanding of the details of the catalytic mechanism can help in the experimental design of novel heterogeneous FLP catalysts.
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Affiliation(s)
- Qiang Wan
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou 350002, China;
| | - Sen Lin
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou 350002, China;
- Correspondence: (S.L.); (H.G.)
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM 87131, USA
- Correspondence: (S.L.); (H.G.)
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19
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Schwedtmann K, Quest M, Guddorf BJ, Keuter J, Hepp A, Feldt M, Droste J, Hansen MR, Lips F. Reactivity of the Bicyclic Amido-Substituted Silicon(I) Ring Compound Si 4 {N(SiMe 3 )Mes} 4 with FLP-Type Character. Chemistry 2021; 27:17361-17368. [PMID: 34636454 PMCID: PMC9297995 DOI: 10.1002/chem.202103101] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Indexed: 01/13/2023]
Abstract
The bicyclic amido‐substituted silicon(I) ring compound Si4{N(SiMe3)Mes}42 (Mes=Mesityl=2,4,6‐Me3C6H2) features enhanced zwitterionic character and different reactivity from the analogous compound Si4{N(SiMe3)Dipp}41 (Dipp=2,6‐iPr2C6H3) due to the smaller mesityl substituents. In a reaction with the N‐heterocyclic carbene NHCMe4
(1,3,4,5‐tetramethyl‐imidazol‐2‐ylidene), we observe adduct formation to give Si4{N(SiMe3)Mes}4 ⋅ NHCMe4
(3). This adduct reacts further with the Lewis acid BH3 to yield the Lewis acid–base complex Si4{N(SiMe3)Mes}4 ⋅ NHCMe4
⋅ BH3 (4). Coordination of AlBr3 to 2 leads to the adduct 5. Calculated proton affinities and fluoride ion affinities reveal highly Lewis basic and very weak Lewis acidic character of the low‐valent silicon atoms in 1 and 2. This is confirmed by protonation of 1 and 2 with Brookharts acid yielding 6 and 7. Reaction with diphenylacetylene only occurs at 111 °C with 2 in toluene and is accompanied by fragmentation of 2 to afford the silacyclopropene 8 and the trisilanorbornadiene species 9.
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Affiliation(s)
- Kevin Schwedtmann
- Westfälische Wilhelms-Universität Münster Institut für Anorganische und Analytische Chemie, Corrensstraße 28-30, 48149, Münster, Germany
| | - Michael Quest
- Westfälische Wilhelms-Universität Münster Institut für Anorganische und Analytische Chemie, Corrensstraße 28-30, 48149, Münster, Germany
| | - Benedikt J Guddorf
- Westfälische Wilhelms-Universität Münster Institut für Anorganische und Analytische Chemie, Corrensstraße 28-30, 48149, Münster, Germany
| | - Jan Keuter
- Westfälische Wilhelms-Universität Münster Institut für Anorganische und Analytische Chemie, Corrensstraße 28-30, 48149, Münster, Germany
| | - Alexander Hepp
- Westfälische Wilhelms-Universität Münster Institut für Anorganische und Analytische Chemie, Corrensstraße 28-30, 48149, Münster, Germany
| | - Milica Feldt
- Westfälische Wilhelms-Universität Münster Organisch Chemisches Institut and Center for Multiscale Theory and Computation, Corrensstraße 36, 48149, Münster, Germany
| | - Jörn Droste
- Westfälische Wilhelms-Universität Münster Institut für Physikalische Chemie, Corrensstraße 28-30, 48149, Münster, Germany
| | - Michael Ryan Hansen
- Westfälische Wilhelms-Universität Münster Institut für Physikalische Chemie, Corrensstraße 28-30, 48149, Münster, Germany
| | - Felicitas Lips
- Westfälische Wilhelms-Universität Münster Institut für Anorganische und Analytische Chemie, Corrensstraße 28-30, 48149, Münster, Germany
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20
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Osi A, Mahaut D, Tumanov N, Fusaro L, Wouters J, Champagne B, Chardon A, Berionni G. Taming the Lewis Superacidity of Non-Planar Boranes: C-H Bond Activation and Non-Classical Binding Modes at Boron. Angew Chem Int Ed Engl 2021; 61:e202112342. [PMID: 34623002 DOI: 10.1002/anie.202112342] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/05/2021] [Indexed: 11/09/2022]
Abstract
The rational design of a geometrically constrained boron Lewis superacid featuring exceptional structure and reactivity is disclosed. It allowed the formation of non-classical electron deficient B-H-B type of bonding which was supported by spectroscopic and X-ray diffraction parameters as well as computational studies. Taming the pyramidal Lewis acid electrophilicity through weak coordinating anion dissociation enabled a series of highly challenging chemical transformations such as Csp 2 -H and Csp 3 -H activation under frustrated Lewis pair regime and the cleavage of Csp 3 -Si bonds. The demonstration of such type of rich chemical behavior and flexibility on a single molecular compound make it a unique mediator of chemical transformations generally restricted to transition metals.
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Affiliation(s)
- Arnaud Osi
- University of Namur: Universite de Namur, Chemistry, BELGIUM
| | - Damien Mahaut
- University of Namur: Universite de Namur, Chemistry, BELGIUM
| | - Nikolay Tumanov
- University of Namur: Universite de Namur, Chemistry, BELGIUM
| | - Luca Fusaro
- University of Namur: Universite de Namur, Chemistry, BELGIUM
| | - Johan Wouters
- University of Namur: Universite de Namur, Chemistry, BELGIUM
| | | | | | - Guillaume Berionni
- University of Namur, Chemistry Department, Rue de Bruxelles 61, 5000, Namur, BELGIUM
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21
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Guo CX, Schwedtmann K, Fidelius J, Hennersdorf F, Dickschat A, Bauzá A, Frontera A, Weigand JJ. Bifunctional Fluorophosphonium Triflates as Intramolecular Frustrated Lewis Pairs: Reversible CO 2 Sequestration and Binding of Carbonyls, Nitriles and Acetylenes. Chemistry 2021; 27:13709-13714. [PMID: 34432918 PMCID: PMC8518062 DOI: 10.1002/chem.202102382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Indexed: 11/07/2022]
Abstract
Electrophilic fluorophosphonium triflates bearing pyridyl (3[OTf]) or imidazolyl (4[OTf])-substituents act as intramolecular frustrated Lewis pairs (FLPs) and reversibly form 1 : 1 adducts with CO2 (5+ and 6+ ). An unusual and labile spirocyclic tetrahedral intermediate (72+ ) is observed in CO2 -pressurized (0.5-2.0 bar) solutions of cation 4+ at low temperatures, as demonstrated by variable-temperature NMR studies, which were confirmed crystallographically. In addition, cations 3+ and 4+ actively bind carbonyls, nitriles and acetylenes by 1,3-dipolar cycloaddition, as shown by selected examples.
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Affiliation(s)
- Chun-Xiang Guo
- Faculty of Chemistry and Food Chemistry, TU Dresden, Chair of Inorganic Molecular Chemistry, 01062, Dresden, Germany
| | - Kai Schwedtmann
- Faculty of Chemistry and Food Chemistry, TU Dresden, Chair of Inorganic Molecular Chemistry, 01062, Dresden, Germany
| | - Jannis Fidelius
- Faculty of Chemistry and Food Chemistry, TU Dresden, Chair of Inorganic Molecular Chemistry, 01062, Dresden, Germany
| | - Felix Hennersdorf
- Faculty of Chemistry and Food Chemistry, TU Dresden, Chair of Inorganic Molecular Chemistry, 01062, Dresden, Germany
| | - Arne Dickschat
- Faculty of Chemistry and Food Chemistry, TU Dresden, Chair of Inorganic Molecular Chemistry, 01062, Dresden, Germany
| | - Antonio Bauzá
- Department of Chemistry, Universitat de Illes Balears, 07122, Palma de Mallorca, Spain
| | - Antonio Frontera
- Department of Chemistry, Universitat de Illes Balears, 07122, Palma de Mallorca, Spain
| | - Jan J Weigand
- Faculty of Chemistry and Food Chemistry, TU Dresden, Chair of Inorganic Molecular Chemistry, 01062, Dresden, Germany
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22
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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23
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Wübker A, Koppe J, Bradtmüller H, Keweloh L, Pleschka D, Uhl W, Hansen MR, Eckert H. Solid-State Nuclear Magnetic Resonance Techniques for the Structural Characterization of Geminal Alane-Phosphane Frustrated Lewis Pairs and Secondary Adducts. Chemistry 2021; 27:13249-13257. [PMID: 34270155 PMCID: PMC8518393 DOI: 10.1002/chem.202102113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Indexed: 11/17/2022]
Abstract
The first comprehensive solid-state nuclear magnetic resonance (NMR) characterization of geminal alane-phosphane frustrated Lewis pairs (Al/P FLPs) is reported. Their relevant NMR parameters (isotropic chemical shifts, direct and indirect 27 Al-31 P spin-spin coupling constants, and 27 Al nuclear electric quadrupole coupling tensor components) have been determined by numerical analysis of the experimental NMR line shapes and compared with values computed from the known crystal structures by using density functional theory (DFT) methods. Our work demonstrates that the 31 P NMR chemical shifts for the studied Al/P FLPs are very sensitive to slight structural inequivalences. The 27 Al NMR central transition signals are spread out over a broad frequency range (>200 kHz), owing to the presence of strong nuclear electric quadrupolar interactions that can be well-reproduced by the static 27 Al wideband uniform rate smooth truncation (WURST) Carr-Purcell-Meiboom-Gill (WCPMG) NMR experiment. 27 Al chemical shifts and quadrupole tensor components offer a facile and clear distinction between three- and four-coordinate aluminum environments. For measuring internuclear Al⋅⋅⋅P distances a new resonance-echo saturation-pulse double-resonance (RESPDOR) experiment was developed by using efficient saturation via frequency-swept WURST pulses. The successful implementation of this widely applicable technique indicates that internuclear Al⋅⋅⋅P distances in these compounds can be measured within a precision of ±0.1 Å.
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Affiliation(s)
- Anna‐Lena Wübker
- Institut für Physikalische Chemie WWU MünsterCorrensstraße 28/3048149MünsterGermany
| | - Jonas Koppe
- Institut für Physikalische Chemie WWU MünsterCorrensstraße 28/3048149MünsterGermany
| | - Henrik Bradtmüller
- Institut für Physikalische Chemie WWU MünsterCorrensstraße 28/3048149MünsterGermany
- Department of Materials EngineeringVitreous Materials LaboratoryFederal University of São CarlosCP 67613565-905São CarlosSPBrazil
| | - Lukas Keweloh
- Institut für Anorganische und Analytische Chemie WWU MünsterCorrensstraße 28/3048149MünsterGermany
| | - Damian Pleschka
- Institut für Anorganische und Analytische Chemie WWU MünsterCorrensstraße 28/3048149MünsterGermany
| | - Werner Uhl
- Institut für Anorganische und Analytische Chemie WWU MünsterCorrensstraße 28/3048149MünsterGermany
| | - Michael Ryan Hansen
- Institut für Physikalische Chemie WWU MünsterCorrensstraße 28/3048149MünsterGermany
| | - Hellmut Eckert
- Institut für Physikalische Chemie WWU MünsterCorrensstraße 28/3048149MünsterGermany
- Instituto de Física de São CarlosUniversidade de São PauloSão CarlosSP13566-590Brazil
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24
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Mahaut D, Chardon A, Mineur L, Berionni G, Champagne B. Rational Development of a Metal-Free Bifunctional System for the C-H Activation of Methane: A Density Functional Theory Investigation. Chemphyschem 2021; 22:1958-1966. [PMID: 34309144 DOI: 10.1002/cphc.202100527] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Indexed: 11/10/2022]
Abstract
The activation or heterolytic splitting of methane, a challenging substrate usually restricted to transition metals, has so far proven elusive in experimental frustrated Lewis pair (FLP) chemistry. In this article, we demonstrate, using density functional theory (DFT), that 1-aza-9-boratriptycene is a conceptually simple intramolecular FLP for the activation of methane. Systematic comparison with other FLP systems allows to gain insight into their reactivity with methane. The thermodynamics and kinetics of methane activation are interpreted by referring to the analysis of the natural charges and by employing the distortion-interaction/activation strain (DIAS) model. These showed that the nature of the Lewis base influences the selectivity over the reaction pathway, with N Lewis bases favoring the deprotonation mechanism and P bases the hydride abstraction one. The lower barrier of activation for 1-aza-9-boratriptycene and the higher products stability are due to a better interaction energy than its counterparts, itself due to electrostatic interactions with the methane moiety, favorable orbital overlaps allowed by the side-attack, and space proximity between the B and N atoms.
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Affiliation(s)
- Damien Mahaut
- Department of Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium
| | - Aurélien Chardon
- Department of Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium
| | - Loïc Mineur
- Department of Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium
| | - Guillaume Berionni
- Department of Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium
| | - Benoît Champagne
- Department of Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles 61, B-5000, Namur, Belgium
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25
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Liu X, Li X, Yao X, Zhao W, Liu L. Effects of Ionic Liquids on the Thermodynamics of Hydrogen Activation by Frustrated Lewis Pairs: A Density Functional Theory Study*. Chemphyschem 2021; 22:968-974. [PMID: 33749087 DOI: 10.1002/cphc.202100093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/15/2021] [Indexed: 11/05/2022]
Abstract
Nowadays, hydrogen activation by frustrated Lewis pairs (FLPs) and their applications are one of the emerging research topics in the field of catalysis. Previous studies have shown that the thermodynamics of this reaction is determined by electronic structures of FLPs and solvents. Herein, we investigated systems consisting of typical FLPs and ionic liquids (ILs), which are well known by their large number of types and excellent solvent effects. The density functional theory (DFT) calculations were performed to study the thermodynamics for H2 activation by both inter- and intra-molecular FLPs, as well as the individual components. The results show that the computed overall Gibbs free energies in ILs are more negative than that computed in toluene. Through the thermodynamics partitioning, we find that ILs favor the H-H cleavage elemental step over the elemental steps of proton attachment, hydride attachment and zwitterionic stabilization. Moreover, the results show that these effects are strongly dependent on the type of FLPs, where intra-molecular FLPs are more affected compared to the inter-molecular FLPs.
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Affiliation(s)
- Xiaoqing Liu
- School of Environment and Safety Engineering, North University of China, Taiyuan, 030051, China
| | - Xue Li
- School of Environment and Safety Engineering, North University of China, Taiyuan, 030051, China
| | - Xiaoqian Yao
- Beijing Key Laboratory of Ionic Liquids Clean Process, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100049, China
| | - Weizhen Zhao
- Beijing Key Laboratory of Ionic Liquids Clean Process, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100049, China
| | - Lei Liu
- Beijing Key Laboratory of Ionic Liquids Clean Process, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100049, China
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26
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Galdeano M, Ruipérez F, Matxain JM. Theoretical Characterization of New Frustrated Lewis Pairs for Responsive Materials. Polymers (Basel) 2021; 13:1573. [PMID: 34068943 DOI: 10.3390/polym13101573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/11/2021] [Accepted: 05/11/2021] [Indexed: 01/08/2023] Open
Abstract
In recent years, responsive materials including dynamic bonds have been widely acclaimed due to their expectation to pilot advanced materials. Within these materials, synthetic polymers have shown to be good candidates. Recently, the so-called frustrated Lewis pairs (FLP) have been used to create responsive materials. Concretely, the activation of diethyl azodicarboxylate (DEAD) by a triphenylborane (TPB) and triphenylphosphine (TPP) based FLP has been recently exploited for the production of dynamic cross-links. In this work, we computationally explore the underlying dynamic chemistry in these materials, in order to understand the nature and reversibility of the interaction between the FLP and DEAD. With this goal in mind, we first characterize the acidity and basicity of several TPB and TPP derivatives using different substituents, such as electron-donating and electron-withdrawing groups. Our results show that strong electron-donating groups increase the acidity of TPB and decrease the basicity of TPP. However, the FLP–DEAD interaction is not mainly dominated by the influence of these substituents in the acidity or basicity of the TPB or TPP systems, but by attractive or repulsive forces between substituents such as hydrogen bonds or steric effects. Based on these results, a new material is proposed based on FLP–DEAD complexes.
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27
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Zhang Q, Li Y, Zhang L, Luo S. Catalytic Asymmetric Disulfuration by a Chiral Bulky Three-Component Lewis Acid-Base. Angew Chem Int Ed Engl 2021; 60:10971-10976. [PMID: 33660896 DOI: 10.1002/anie.202101569] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/02/2021] [Indexed: 01/07/2023]
Abstract
A three-component Lewis acid-base (Lewis trio) involving a bulky chiral primary amine, B(C6 F5 )3 and a bulky tertiary amine has been developed as an effective enamine catalyst for enantioselective disulfuration reactions. The bulky tertiary amine was found to activate a bulky primary-tertiary diamine-borane Lewis pair for enamine catalysis via frustrated interaction. The resulted chiral bulky Lewis trio (BLT) allows for the construction of chiral disulfides via direct disulfuration with β-ketocarbonyls or α-branched aldehydes in a practical and highly stereocontrolled manner.
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Affiliation(s)
- Qi Zhang
- Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,Department of Chemistry, University of Chinese Academy of Sciences, Beijing, 100490, China
| | - Yao Li
- Center of Basic Molecular Science, Department of Chemistry, Tsinghua University, Beijing, China
| | - Long Zhang
- Center of Basic Molecular Science, Department of Chemistry, Tsinghua University, Beijing, China
| | - Sanzhong Luo
- Center of Basic Molecular Science, Department of Chemistry, Tsinghua University, Beijing, China
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28
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Holtkamp P, Poier D, Neumann B, Stammler H, Mitzel NW. Exploring the Reactivity of a Frustrated Sn/P Lewis Pair: The Highly Selective Complexation of the cis-Azobenzene Photoisomer. Chemistry 2021; 27:3793-3798. [PMID: 33284497 PMCID: PMC7986075 DOI: 10.1002/chem.202004600] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Indexed: 12/16/2022]
Abstract
The reactivity of the geminal frustrated Lewis pair (FLP) (F5 C2 )3 SnCH2 P(tBu)2 (1) was explored by reacting it with a variety of small molecules (PhOCN, PhNCS, PhCCH, tBuCCH, H3 CC(O)CH=CH2 , Ph[C(O)]2 Ph, PhN=NPh and Me3 SiCHN2 ), featuring polar or non-polar multiple bonds and/or represent α,β-unsaturated systems. While most adducts are formed readily, the binding of azobenzene requires UV-induced photoisomerization, which results in the highly selective complexation of cis-azobenzene. In the case of benzil, the reaction does not lead to the expected 1,2- or 1,4-addition products, but to the non-stereoselective (tBu)2 PCH2 -transfer to a prochiral keto function of benzil. All adducts of 1 were characterised by means of multinuclear NMR spectroscopy, elemental analyses and X-ray diffraction experiments.
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Affiliation(s)
- Philipp Holtkamp
- Lehrstuhl für Anorganische Chemie und StrukturchemieFakultät für ChemieUniversität BielefeldUniversitätsstraße 2533615BielefeldGermany
| | - Dario Poier
- Lehrstuhl für Anorganische Chemie und StrukturchemieFakultät für ChemieUniversität BielefeldUniversitätsstraße 2533615BielefeldGermany
| | - Beate Neumann
- Lehrstuhl für Anorganische Chemie und StrukturchemieFakultät für ChemieUniversität BielefeldUniversitätsstraße 2533615BielefeldGermany
| | - Hans‐Georg Stammler
- Lehrstuhl für Anorganische Chemie und StrukturchemieFakultät für ChemieUniversität BielefeldUniversitätsstraße 2533615BielefeldGermany
| | - Norbert W. Mitzel
- Lehrstuhl für Anorganische Chemie und StrukturchemieFakultät für ChemieUniversität BielefeldUniversitätsstraße 2533615BielefeldGermany
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29
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Omaña AA, Green RK, Kobayashi R, He Y, Antoniuk ER, Ferguson MJ, Zhou Y, Veinot JGC, Iwamoto T, Brown A, Rivard E. Frustrated Lewis Pair Chelation as a Vehicle for Low-Temperature Semiconductor Element and Polymer Deposition. Angew Chem Int Ed Engl 2021; 60:228-231. [PMID: 32960472 DOI: 10.1002/anie.202012218] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Indexed: 01/03/2023]
Abstract
The stabilization of silicon(II) and germanium(II) dihydrides by an intramolecular Frustrated Lewis Pair (FLP) ligand, PB, i Pr2 P(C6 H4 )BCy2 (Cy=cyclohexyl) is reported. The resulting hydride complexes [PB{SiH2 }] and [PB{GeH2 }] are indefinitely stable at room temperature, yet can deposit films of silicon and germanium, respectively, upon mild thermolysis in solution. Hallmarks of this work include: 1) the ability to recycle the FLP phosphine-borane ligand (PB) after element deposition, and 2) the single-source precursor [PB{SiH2 }] deposits Si films at a record low temperature from solution (110 °C). The dialkylsilicon(II) adduct [PB{SiMe2 }] was also prepared, and shown to release poly(dimethylsilane) [SiMe2 ]n upon heating. Overall, this study introduces a "closed loop" deposition strategy for semiconductors that steers materials science away from the use of harsh reagents or high temperatures.
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Affiliation(s)
- Alvaro A Omaña
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta, T6G 2G2, Canada
| | - Rachel K Green
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta, T6G 2G2, Canada
| | - Ryo Kobayashi
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai, 980-8578, Japan
| | - Yingjie He
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta, T6G 2G2, Canada
| | - Evan R Antoniuk
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta, T6G 2G2, Canada
| | - Michael J Ferguson
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta, T6G 2G2, Canada
| | - Yuqiao Zhou
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta, T6G 2G2, Canada
| | - Jonathan G C Veinot
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta, T6G 2G2, Canada
| | - Takeaki Iwamoto
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai, 980-8578, Japan
| | - Alex Brown
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta, T6G 2G2, Canada
| | - Eric Rivard
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta, T6G 2G2, Canada
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30
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Hasenbeck M, Ahles S, Averdunk A, Becker J, Gellrich U. Formation of Nucleophilic Allylboranes from Molecular Hydrogen and Allenes Catalyzed by a Pyridonate Borane that Displays Frustrated Lewis Pair Reactivity. Angew Chem Int Ed Engl 2020; 59:23885-23891. [PMID: 32926511 PMCID: PMC7814673 DOI: 10.1002/anie.202011790] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Indexed: 11/05/2022]
Abstract
Here we report the in situ generation of nucleophilic allylboranes from H2 and allenes mediated by a pyridonate borane that displays frustrated‐Lewis‐pair reactivity. Experimental and computational mechanistic investigations reveal that upon H2 activation, the covalently bound pyridonate substituent becomes a datively bound pyridone ligand. Dissociation of the formed pyridone borane complex liberates Piers borane and enables a hydroboration of the allene. The allylboranes generated in this way are reactive towards nitriles. A catalytic protocol for the formation of allylboranes from H2 and allenes and the allylation of nitriles has been devised. This catalytic reaction is a conceptually new way to use molecular H2 in organic synthesis.
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Affiliation(s)
- Max Hasenbeck
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Sebastian Ahles
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Arthur Averdunk
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Jonathan Becker
- Institut für Anorganische und Analytische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
| | - Urs Gellrich
- Institut für Organische Chemie, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany
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31
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Holtrop F, Jupp AR, Kooij BJ, van Leest NP, de Bruin B, Slootweg JC. Single-Electron Transfer in Frustrated Lewis Pair Chemistry. Angew Chem Int Ed Engl 2020; 59:22210-22216. [PMID: 32840947 PMCID: PMC7756365 DOI: 10.1002/anie.202009717] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Indexed: 02/05/2023]
Abstract
Frustrated Lewis pairs (FLPs) are well known for their ability to activate small molecules. Recent reports of radical formation within such systems indicate single-electron transfer (SET) could play an important role in their chemistry. Herein, we investigate radical formation upon reacting FLP systems with dihydrogen, triphenyltin hydride, or tetrachloro-1,4-benzoquinone (TCQ) both experimentally and computationally to determine the nature of the single-electron transfer (SET) events; that is, being direct SET to B(C6 F5 )3 or not. The reactions of H2 and Ph3 SnH with archetypal P/B FLP systems do not proceed via a radical mechanism. In contrast, reaction with TCQ proceeds via SET, which is only feasible by Lewis acid coordination to the substrate. Furthermore, SET from the Lewis base to the Lewis acid-substrate adduct may be prevalent in other reported examples of radical FLP chemistry, which provides important design principles for radical main-group chemistry.
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Affiliation(s)
- Flip Holtrop
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | - Andrew R. Jupp
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | - Bastiaan J. Kooij
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | - Nicolaas P. van Leest
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | - Bas de Bruin
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | - J. Chris Slootweg
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
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32
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Abstract
Phosphagallenes (1 a/1 b) featuring double bonds between phosphorus and gallium were synthesized by reaction of (phosphanyl)phosphaketenes with the gallium carbenoid Ga(Nacnac) (Nacnac=HC[C(Me)N(2,6-i-Pr2 C6 H3 )]2 ). The stability of these species is dependent on the saturation of the phosphanyl moiety. 1 a, which bears an unsaturated phosphanyl ring, rearranges in solution to yield a spirocyclic compound (2) which contains a P=P bond. The saturated variant 1 b is stable even at elevated temperatures. 1 b behaves as a frustrated Lewis pair capable of activation of H2 and forms a 1:1 adduct with CO2 .
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Affiliation(s)
- Daniel W. N. Wilson
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory12 Mansfield RoadOxfordOX1 3TAUK
| | - Joey Feld
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory12 Mansfield RoadOxfordOX1 3TAUK
| | - Jose M. Goicoechea
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory12 Mansfield RoadOxfordOX1 3TAUK
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33
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Iashin V, Berta D, Chernichenko K, Nieger M, Moslova K, Pápai I, Repo T. Metal-Free C-H Borylation of N-Heteroarenes by Boron Trifluoride. Chemistry 2020; 26:13873-13879. [PMID: 32478432 PMCID: PMC7702085 DOI: 10.1002/chem.202001436] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 05/28/2020] [Indexed: 01/08/2023]
Abstract
Organoboron compounds are essential reagents in modern C-C coupling reactions. Their synthesis via catalytic C-H borylation by main group elements is emerging as a powerful tool alternative to transition metal based catalysis. Herein, a straightforward metal-free synthesis of aryldifluoroboranes from BF3 and heteroarenes is reported. The reaction is assisted by sterically hindered amines and catalytic amounts of thioureas. According to computational studies the reaction proceeds via frustrated Lewis pair (FLP) mechanism. The obtained aryldifluoroboranes are further stabilized against destructive protodeborylation by converting them to the corresponding air stable tetramethylammonium organotrifluoroborates.
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Affiliation(s)
- Vladimir Iashin
- Department of ChemistryUniversity of HelsinkiA. I. Virtasen aukio, 100014HelsinkiFinland
| | - Dénes Berta
- Institute of Organic ChemistryResearch Centre for Natural SciencesMagyar tudósok körútja 21117BudapestHungary
| | - Konstantin Chernichenko
- Department of ChemistryUniversity of HelsinkiA. I. Virtasen aukio, 100014HelsinkiFinland
- Present address: API Small Molecule DevelopmentJanssen Pharmaceutica N.V.Turnhoutseweg 302340BeerseBelgium
| | - Martin Nieger
- Department of ChemistryUniversity of HelsinkiA. I. Virtasen aukio, 100014HelsinkiFinland
| | - Karina Moslova
- Department of ChemistryUniversity of HelsinkiA. I. Virtasen aukio, 100014HelsinkiFinland
| | - Imre Pápai
- Institute of Organic ChemistryResearch Centre for Natural SciencesMagyar tudósok körútja 21117BudapestHungary
| | - Timo Repo
- Department of ChemistryUniversity of HelsinkiA. I. Virtasen aukio, 100014HelsinkiFinland
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34
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Pacholak P, Gontarczyk K, Kamiński R, Durka K, Luliński S. Boronate Covalent and Hybrid Organic Frameworks Featuring P III and P=O Lewis Base Sites. Chemistry 2020; 26:12758-12768. [PMID: 32468680 PMCID: PMC7589431 DOI: 10.1002/chem.202001960] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/25/2020] [Indexed: 11/16/2022]
Abstract
Two covalent organic frameworks comprising Lewis basic PIII centers and Lewis acidic boron atoms were prepared by poly-condensation reactions of newly obtained tris(4-diisopropoxyborylphenyl)phosphine with 2,3,6,7,10,11-hexahydroxytriphenylene and 2,3,6,7-tetrahydroxy-9,10-dimethylanthracene. Obtained materials exhibit significant sorption of dihydrogen (100 cm3 g-1 at 1 bar at 77 K), methane (20 cm3 g-1 at 1 bar at 273 K) and carbon dioxide (50 cm3 g-1 at 1 bar at 273 K). They were exploited as solid-state ligands for coordination of Pd0 centers. Alternatively, in a bottom-up approach, boronated phosphine was treated with Pd2 dba3 and poly-condensated, yielding hybrid materials where the polymer networks are formed by means of covalent boronate linkages and coordination P-Pd bonds. In addition, the analogous materials based on phosphine oxide were synthesized. The DFT calculations on framework-guest interactions revealed that the behavior of adjacent boron and phosphorus/phosphine oxide centers is reminiscent of that found in Frustrated Lewis Pairs and may improve sorption of selected molecules.
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Affiliation(s)
- Piotr Pacholak
- Faculty of ChemistryWarsaw University of TechnologyNoakowskiego 300-664WarsawPoland
| | - Krzysztof Gontarczyk
- Faculty of ChemistryWarsaw University of TechnologyNoakowskiego 300-664WarsawPoland
| | - Radosław Kamiński
- Department of ChemistryUniversity of WarsawŻwirki i Wigury 10102-089WarsawPoland
| | - Krzysztof Durka
- Faculty of ChemistryWarsaw University of TechnologyNoakowskiego 300-664WarsawPoland
| | - Sergiusz Luliński
- Faculty of ChemistryWarsaw University of TechnologyNoakowskiego 300-664WarsawPoland
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35
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Holtkamp P, Glodde T, Poier D, Neumann B, Stammler H, Mitzel NW. An Adduct of Sulfur Monoxide to a Frustrated Sn/P Lewis Pair. Angew Chem Int Ed Engl 2020; 59:17388-17392. [PMID: 32558235 PMCID: PMC7540458 DOI: 10.1002/anie.202007653] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Indexed: 11/14/2022]
Abstract
The geminal frustrated Lewis pair (F5 C2 )3 SnCH2 P(tBu)2 (1) reacted with N-sulfinylaniline PhNSO to afford the first sulfur monoxide adduct of a main group metal, (F5 C2 )3 SnCH2 P(tBu)2 ⋅SO (2), which contains a SnCPSO ring. The second product is a phenylnitrene adduct of 1. The surprising stability of 2 was compared with the stabilities of the so far inaccessible O2 and S2 adducts of 1. Attempts to prepare these from 1 and the elemental chalcogens (O2 , S8 , Se∞ , Te∞ ) led to four-membered SnCPE ring systems. Quantum-chemical investigations of 2 demonstrate the bond polarity of the SO unit to stabilize 2.
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Affiliation(s)
- Philipp Holtkamp
- Lehrstuhl für Anorganische Chemie und StrukturchemieFakultät für ChemieUniversität BielefeldUniversitätsstraße 2533615BielefeldGermany
| | - Timo Glodde
- Lehrstuhl für Anorganische Chemie und StrukturchemieFakultät für ChemieUniversität BielefeldUniversitätsstraße 2533615BielefeldGermany
| | - Dario Poier
- Lehrstuhl für Anorganische Chemie und StrukturchemieFakultät für ChemieUniversität BielefeldUniversitätsstraße 2533615BielefeldGermany
| | - Beate Neumann
- Lehrstuhl für Anorganische Chemie und StrukturchemieFakultät für ChemieUniversität BielefeldUniversitätsstraße 2533615BielefeldGermany
| | - Hans‐Georg Stammler
- Lehrstuhl für Anorganische Chemie und StrukturchemieFakultät für ChemieUniversität BielefeldUniversitätsstraße 2533615BielefeldGermany
| | - Norbert W. Mitzel
- Lehrstuhl für Anorganische Chemie und StrukturchemieFakultät für ChemieUniversität BielefeldUniversitätsstraße 2533615BielefeldGermany
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36
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Andrews RJ, Stephan DW. Isolable Anionic, Neutral and Cationic Radicals from Reactions of N,N'-Dimesityldiamidocarbene and Lewis Acids. Chemistry 2020; 26:7194-7198. [PMID: 32149432 DOI: 10.1002/chem.202001191] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Indexed: 01/04/2023]
Abstract
B(C6 F5 )3 undergoes nucleophilic attack by N,N'-dimesityldiamidocarbene (DAC) with fluoride transfer to the boron center, resulting in a new zwitterion (1). This B-F fluoride can be replaced or abstracted to give the corresponding hydride (2) or triflate (3) derivatives or the corresponding cation (4). These species are reduced with KC8 or Cp2 Co to give isolable anionic and neutral radicals (5-8). Similarly, the [Ph3 C] cation undergoes nucleophilic attack by DAC resulting in the spontaneous formation of the radical cation (9).
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Affiliation(s)
- Ryan J Andrews
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON, M5S 3H4, Canada
| | - Douglas W Stephan
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON, M5S 3H4, Canada
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37
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Bismuto A, Nichol GS, Duarte F, Cowley MJ, Thomas SP. Characterization of the Zwitterionic Intermediate in 1,1-Carboboration of Alkynes. Angew Chem Int Ed Engl 2020; 59:12731-12735. [PMID: 32343867 DOI: 10.1002/anie.202003468] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Indexed: 11/12/2022]
Abstract
The reaction of a Lewis acidic borane with an alkyne is a key step in a diverse range of main group transformations. Alkyne 1,1-carboboration, the Wrackmeyer reaction, is an archetypal transformation of this kind. 1,1-Carboboration has been proposed to proceed through a zwitterionic intermediate. We report the isolation and spectroscopic, structural and computational characterization of the zwitterionic intermediates generated by reaction of B(C6 F5 )3 with alkynes. The stepwise reactivity of the zwitterion provides new mechanistic insight for 1,1-carboboration and wider B(C6 F5 )3 catalysis. Making use of intramolecular stabilization by a ferrocene substituent, we have characterized the zwitterionic intermediate in the solid state and diverted reactivity towards alkyne cyclotrimerization.
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Affiliation(s)
- Alessandro Bismuto
- EaStCHEM, School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Gary S Nichol
- EaStCHEM, School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Fernanda Duarte
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Michael J Cowley
- EaStCHEM, School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Stephen P Thomas
- EaStCHEM, School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
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38
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Yanagisawa T, Mizuhata Y, Tokitoh N. Additive-Free Conversion of Internal Alkynes by Phosphanylalumanes: Production of Phosphorus/Aluminum Frustrated Lewis Pairs. Chempluschem 2020; 85:933-942. [PMID: 32401435 DOI: 10.1002/cplu.202000239] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/24/2020] [Accepted: 04/29/2020] [Indexed: 11/10/2022]
Abstract
Internal and terminal alkynes react with phosphanylalumanes, i. e., P-Al single-bond species, through heating but without any additional additives. The reactions with internal alkynes afforded the corresponding adducts with cis-1,2-form in moderate yields (54-80 %). In addition, alkyne adducts thus obtained function as P/Al-based C2 -vicinal FLPs, and the FLP addition reactions with benzaldehyde and CO2 were demonstrated. Furthermore, in the reaction of 2,4,6-trimethylphenyl-substituted alkyne adducts with dimethyl acetylenedicarboxylate, an unexpected CAr -CMe bond cleavage characteristic of this system was demonstrated.
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Affiliation(s)
- Tatsuya Yanagisawa
- Institute for Chemical Research, Kyoto University Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Yoshiyuki Mizuhata
- Institute for Chemical Research, Kyoto University Gokasho, Uji, Kyoto, 611-0011, Japan.,Integrated Research Consortium on Chemical Sciences Uji, Kyoto, Japan
| | - Norihiro Tokitoh
- Institute for Chemical Research, Kyoto University Gokasho, Uji, Kyoto, 611-0011, Japan.,Integrated Research Consortium on Chemical Sciences Uji, Kyoto, Japan
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39
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Hidalgo N, Moreno JJ, Pérez-Jiménez M, Maya C, López-Serrano J, Campos J. Evidence for Genuine Bimetallic Frustrated Lewis Pair Activation of Dihydrogen with Gold(I)/Platinum(0) Systems. Chemistry 2020; 26:5982-5993. [PMID: 31971290 DOI: 10.1002/chem.201905793] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/22/2020] [Indexed: 01/07/2023]
Abstract
A joint experimental/computational effort to elucidate the mechanism of dihydrogen activation by a gold(I)/platinum(0) metal-only frustrated Lewis pair (FLP) is described herein. The drastic effects on H2 activation derived from subtle ligand modifications have also been investigated. The importance of the balance between bimetallic adduct formation and complete frustration has been interrogated, providing for the first time evidence for genuine metal-only FLP reactivity in solution. The origin of a strong inverse kinetic isotopic effect has also been clarified, offering further support for the proposed bimetallic FLP-type cleavage of dihydrogen.
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Affiliation(s)
- Nereida Hidalgo
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and, University of Sevilla, Avenida Américo Vespucio 49, 41092, Sevilla, Spain
| | - Juan José Moreno
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and, University of Sevilla, Avenida Américo Vespucio 49, 41092, Sevilla, Spain
| | - Marina Pérez-Jiménez
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and, University of Sevilla, Avenida Américo Vespucio 49, 41092, Sevilla, Spain
| | - Celia Maya
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and, University of Sevilla, Avenida Américo Vespucio 49, 41092, Sevilla, Spain
| | - Joaquín López-Serrano
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and, University of Sevilla, Avenida Américo Vespucio 49, 41092, Sevilla, Spain
| | - Jesús Campos
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and, University of Sevilla, Avenida Américo Vespucio 49, 41092, Sevilla, Spain
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40
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Li J, Mück-Lichtenfeld C, Daniliuc CG, Kehr G, Erker G. Using the Secondary PH/BH Functional Groups of an Active Geminal Frustrated Lewis Pair for Carbon Monoxide Reduction and Reactions with Nitriles and Isonitriles. Angew Chem Int Ed Engl 2020; 59:12477-12483. [PMID: 31994804 DOI: 10.1002/anie.202000612] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Indexed: 11/10/2022]
Abstract
Reaction of the secondary alkynyl(Mes*)PH phosphane 2 with (Fmes)BH2 ⋅SMe2 gives the geminal PH/BH frustrated Lewis pair (FLP) 3. The PH and the BH functions are jointly used in the reduction of carbon monoxide under mild reaction conditions to give the [P]-CH2 -O-[B] product. A subsequent cycloaddition sequence results in the liberation of formaldehyde. The FLP 3 reacts with benzonitrile to give a P-benzamidine, and it couples two isonitriles at the FLP framework.
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Affiliation(s)
- Jun Li
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Christian Mück-Lichtenfeld
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
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41
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Bai Y, Wang H, He J, Zhang Y. Rapid and Scalable Access to Sequence-Controlled DHDM Multiblock Copolymers by FLP Polymerization. Angew Chem Int Ed Engl 2020; 59:11613-11619. [PMID: 32237265 DOI: 10.1002/anie.202004013] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 03/26/2020] [Indexed: 12/25/2022]
Abstract
An immortal N-(diphenylphosphanyl)-1,3-diisopropyl-4,5-dimethyl-1,3-dihydro-2H-imidazol-2-imine/diisobutyl (2,6-di-tert-butyl-4-methylphenoxy) aluminum (P(NIi Pr)Ph2 /(BHT)Ali Bu2 )-based frustrated Lewis pair (FLP) polymerization strategy is presented for rapid and scalable synthesis of the sequence-controlled multiblock copolymers at room temperature. Without addition of extra initiator or catalyst and complex synthetic procedure, this method enabled a tripentacontablock copolymer (n=53, k=4, dpn =50) to be achieved with the highest reported block number (n=53) and molecular weight (Mn =310 kg mol-1 ) within 30 min. More importantly, this FLP polymerization strategy provided access to the multiblock copolymers with tailored properties by precisely adjusting the monomer sequence and block numbers.
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Affiliation(s)
- Yun Bai
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin, 130012, China
| | - Huaiyu Wang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin, 130012, China
| | - Jianghua He
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin, 130012, China
| | - Yuetao Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin, 130012, China
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42
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Abstract
Rare-earth metal cations have been used rarely as Lewis-acidic components in the chemistry of frustrated Lewis pairs (FLPs). Herein, we report the first cerium/phosphorus system (2) employing a heptadentate N4 P3 ligand, which exhibits triple FLP-type reactivity towards a series of organic substrates, including isocyanates, isothiocyanates, diazomethane, and azides on a single rare-earth Lewis acidic Ce center. This result shows that the Ce center and three P atoms in 2 could simultaneously activate three equivalents of small molecules under mild conditions. This study broadens the diversity of FLPs and demonstrates that rare earth based FLP exhibit unique properties compared with other FLP systems.
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Affiliation(s)
- Xiong Sun
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China
| | - Wei Su
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China
| | - Kaiying Shi
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China
| | - Zhuoyi Xie
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China
| | - Congqing Zhu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China
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43
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Dong S, Daniliuc CG, Kehr G, Erker G. Formation of Active Cyclic Five-membered Frustrated Phosphane/Borane Lewis Pairs and their Cycloaddition Reactions. Chemistry 2019; 26:745-753. [PMID: 31660668 DOI: 10.1002/chem.201904919] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Indexed: 12/14/2022]
Abstract
The cyclic five-membered frustrated phosphane/borane Lewis pairs 11 a, b featuring the bulky octaethylhydrindacenyl- (Eind) substituent or its mono-bromo derivative (Br Eind) at phosphorus are monomeric at room temperature. The reactive frustrated Lewis pairs (FLPs) cleave dihydrogen. The cyclic FLP 11 b (Br Eind) undergoes 1,2-P/B addition to ethylene to give the zwitterionic heteronorbornane derivative 14 b. It reacts similarly with the carbon-carbon double bond of norbornene. With a variety of organic π-reagents, the cyclic FLP 11 b often undergoes reaction sequences reminiscent of the Alder-Rickert reaction: the cycloaddition reaction is followed by rapid cycloreversion to form new five-membered heterocyclic FLP products with extrusion of ethene. Reactions of 11 b with benzaldehyde or with acetylenes follow this reaction pattern.
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Affiliation(s)
- Shunxi Dong
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149, Münster, Germany.,Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064, P. R. China
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149, Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149, Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149, Münster, Germany
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44
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Carmona M, Ferrer J, Rodríguez R, Passarelli V, Lahoz FJ, García-Orduña P, Cañadillas-Delgado L, Carmona D. Reversible Activation of Water by an Air- and Moisture-Stable Frustrated Rhodium Nitrogen Lewis Pair. Chemistry 2019; 25:13665-13670. [PMID: 31353749 DOI: 10.1002/chem.201902452] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/12/2019] [Indexed: 12/15/2022]
Abstract
[Cp*Rh(κ3 N,N',P-L)][SbF6 ] (Cp*=C5 Me5 ), bearing a guanidine-derived phosphano ligand L, behaves as a "dormant" frustrated Lewis pair and activates H2 and H2 O in a reversible manner. When D2 O is employed, a facile H/D exchange at the Cp* ring takes place through sequential C(sp3 )-H bond activation.
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Affiliation(s)
- María Carmona
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Joaquina Ferrer
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Ricardo Rodríguez
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Vincenzo Passarelli
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain.,Centro Universitario de la Defensa, Ctra. Huesca s/n, 50090, Zaragoza, Spain
| | - Fernando J Lahoz
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Pilar García-Orduña
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Laura Cañadillas-Delgado
- Centro Universitario de la Defensa, Ctra. Huesca s/n, 50090, Zaragoza, Spain.,Institut Laue-Langevin, 71 Avenue des Martyrs, Grenoble, 38042, France
| | - Daniel Carmona
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain
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45
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Abstract
The geminal frustrated Lewis pair (FLP) tBu2 PCH2 BPh2 (1) reacts with phenyl-, mesityl-, and tert-butyl azide affording, respectively, six, five, and four-membered rings as isolable products. DFT calculations revealed that the formation of all products proceeds via the six-membered ring structure, which is thermally stable with an N-phenyl group, but rearranges when sterically more encumbered Mes-N3 and tBu-N3 are used. The reaction of 1 with Me3 Si-N3 is believed to follow the same course, yet subsequent N2 elimination occurs to afford a four-membered heterocycle (5), which can be considered as a formal FLP-trimethylsilylnitrene adduct. Compound 5 reacts with hydrochloric acid or tetramethylammonium fluoride and showed frustrated Lewis pair reactivity towards phenylisocyanate.
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Affiliation(s)
- Devin H. A. Boom
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041090 GDAmsterdamThe Netherlands
| | - Andrew R. Jupp
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041090 GDAmsterdamThe Netherlands
| | - Martin Nieger
- Department of ChemistryUniversity of HelsinkiA. I. Virtasen aukio 1, PO Box 5500014HelsinkiFinland
| | - Andreas W. Ehlers
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041090 GDAmsterdamThe Netherlands
- Department of Chemistry, Science FacultyUniversity of JohannesburgPO Box 254Auckland Park, JohannesburgSouth Africa
| | - J. Chris Slootweg
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 9041090 GDAmsterdamThe Netherlands
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46
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Knitsch R, Özgün T, Chen GQ, Kehr G, Erker G, Hansen MR, Eckert H. Dihydrogen Splitting by Intramolecular Borane-Phosphane Frustrated Lewis Pairs: A Comprehensive Characterization Strategy Using Solid State NMR and DFT Calculations. Chemphyschem 2019; 20:1837-1849. [PMID: 31127674 DOI: 10.1002/cphc.201900406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/23/2019] [Indexed: 11/07/2022]
Abstract
Four hydrogenated intramolecular phosphane-borane frustrated Lewis pair (B/P FLP) compounds bearing unsaturated cyclic or aromatic carbon backbones have been synthesized and structurally characterized using 11 B, 31 P, 1 H and 2 H solid-state NMR spectroscopy. A comparison of the spectra with those of the corresponding free B/P FLPs shows that both 11 B isotropic chemical shifts as well as nuclear electric quadrupolar coupling constants decrease significantly upon FLP hydrogenation, revealing the breakage of the partial B-P bond present in the starting materials. Likewise, the 31 P isotropic chemical shift, the chemical shift anisotropy, and the asymmetry parameter decrease significantly upon FLP hydrogenation, reflecting the formation of a more symmetric, C3v -like local environment. 11 B{31 P} rotational echo double resonance (REDOR) experiments can be used to measure the B-P internuclear distance (about 3.2 Å) of these compounds. Observation of the hydrogen atoms bound to the Lewis centers is best accomplished via 31 P{1 H} and 11 B{1 H} cross-polarization-heteronuclear correlation experiments or by direct observation of the 2 H MAS NMR signals on especially prepared FLP-D2 adducts. For accurately measuring the phosphorus-deuterium distance via 31 P{2 H} rotational echo adiabatic passage double resonance (REAPDOR), it is essential to take the secondary dipolar coupling of 31 P with the boron-bonded 2 H nuclei explicitly into consideration, by simulating a 2 HP -31 P-2 HB three-spin system based on structural input. All of the experimental NMR interaction parameters are found in excellent agreement with values calculated by DFT methods, using the geometries obtained either by energy optimization or from single-crystal structures.
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Affiliation(s)
- Robert Knitsch
- Institut für Physikalische Chemie, WWU Münster, Corrensstraße 30, D-41849, Münster, Germany
| | - Thomas Özgün
- Organisch-Chemisches Institut, WWU Münster, Corrensstraße 40, D-41849, Münster, Germany
| | - Guo-Qiang Chen
- Organisch-Chemisches Institut, WWU Münster, Corrensstraße 40, D-41849, Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut, WWU Münster, Corrensstraße 40, D-41849, Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut, WWU Münster, Corrensstraße 40, D-41849, Münster, Germany
| | - Michael Ryan Hansen
- Institut für Physikalische Chemie, WWU Münster, Corrensstraße 30, D-41849, Münster, Germany
| | - Hellmut Eckert
- Institut für Physikalische Chemie, WWU Münster, Corrensstraße 30, D-41849, Münster, Germany.,Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP 13566-590, Brazil
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47
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Pleschka D, Uebing M, Lange M, Hepp A, Wübker AL, Hansen MR, Würthwein EU, Uhl W. Al/P- and Ga/P-Based Frustrated Lewis Pairs and Electronically Unsaturated Substrates: Ring Cleavage and Ring Closure, C-C and C-N Bond Formation. Chemistry 2019; 25:9315-9325. [PMID: 31081975 DOI: 10.1002/chem.201901659] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Indexed: 12/20/2022]
Abstract
Al/P- and Ga/P-based frustrated Lewis pairs (FLPs) reacted with an azirine under mild conditions under cleavage of the heterocycle on two different positions. Opening of the C-C bond yielded an unusual nitrile-ylide adduct in which a C-N moiety coordinated to the FLP backbone. Cleavage of a C-N bond afforded the thermodynamically favored enamine adduct with the N atom bound to P and Al or Ga atoms. Ring closure was observed upon treatment of an Al/P FLP with electronically unsaturated substrates (4-(1-cyclohexenyl)-1-aza-but-1-en-3-ynes) and yielded by C-N bond formation hexahydroquinoline derivatives, which coordinated to the FLP through P-C and Al-C bonds. Diphenylcyclopropenone showed a diverse reactivity, which depending on steric shielding and the polarizing effect of Al or Ga atoms afforded different products. An AltBu2 /P FLP yielded an adduct with the C=O group coordinated to P and Al. The dineopentyl derivative gave an equilibrium mixture consisting of a similar product and a simple adduct with O bound to Al and a three-coordinate P atom. Both compounds co-crystallize. The Ga/P FLP only formed the simple adduct with the same substrate. Rearrangement resulted in all cases in C3 -ring cleavage and migration of a mesityl group from P to a former ring C atom by C-C bond formation. Diphenylthiocyclopropenone (evidence for the presence of P=C bonds) and an imine derivative afforded similar products.
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Affiliation(s)
- Damian Pleschka
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 30, 48149, Münster, Germany
| | - Marten Uebing
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 30, 48149, Münster, Germany
| | - Merten Lange
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 30, 48149, Münster, Germany
| | - Alexander Hepp
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 30, 48149, Münster, Germany
| | - Anna-Lena Wübker
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 30, 48149, Münster, Germany
| | - Michael Ryan Hansen
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 30, 48149, Münster, Germany
| | - Ernst-Ulrich Würthwein
- Organisch-Chemisches Institut and Center for Multiscale Theory, and Computation (CMTC), Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149, Münster, Germany
| | - Werner Uhl
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 30, 48149, Münster, Germany
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48
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Brož B, Marek A. Tritiodefluorination of alkyl C-F groups. J Labelled Comp Radiopharm 2019; 62:743-750. [PMID: 31267564 DOI: 10.1002/jlcr.3782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/10/2019] [Accepted: 06/28/2019] [Indexed: 11/09/2022]
Abstract
A straightforward methodology of fluorine substitution by tritium/deuterium is reported. The described method is selective towards the F─C (sp3 ) group and leaves both the aromatic F─C (sp2 ) and F2 ─C (sp3 ) moieties unaffected. Alkylfluorides, readily synthesized from appropriate alcohols by treatment with diethylaminosulfur trifluoride (DAST) reagent in an overall yield up to 76%, undergoes activation with the boron-based Lewis acid B(C6 F5 )3 , and stoichiometric in situ reduction with a tritide/deuteride reagent-the [TMP2(3) H][2(3) HB(C6 F5 )3 ] system of frustrated Lewis pair. This methodology provides an isolated yield of up to 93% of regio-specifically labeled small organic compounds with superior 2 H-enrichment of over 95%. The specific activity of prepared 1-(2-[3 H]-ethyl)naphthalene was determined at 29.0 Ci/mmol. The site selectivity of the Lewis acid/ [TMP2(3) H][2(3) HB(C6 F5 )3 ] approach is orthogonal to currently used methods and allows for isotopic labeling of complementary positions in molecules. Reported labeling methodology proceeds well at ultra-mild reaction conditions (220 mbar of T2 ), allowing very low consumption of the radioactive source (4.2 Ci/156 GBq), and producing limited amount of radioactive waste.
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Affiliation(s)
- Břetislav Brož
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Prague, Czech Republic
| | - Aleš Marek
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Prague, Czech Republic
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Doubková S, Marek A. Frustrated Lewis pairs: A real alternative to deuteride/tritide reductions. J Labelled Comp Radiopharm 2019; 62:729-742. [PMID: 31170318 DOI: 10.1002/jlcr.3774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/17/2019] [Accepted: 05/17/2019] [Indexed: 11/11/2022]
Abstract
Deuterium- and tritium-labeled compounds play a principal role in tracing of biologically active molecules in complicated biochemical systems. The state-of-the-art techniques using noble metal catalysts or strong reducing agents often suffers from low functional group tolerances, poor selectivity, tricky or multistep synthesis of reagents, and low specific activity of the labeled product. Herein, we demonstrate a mild and nonmetallic technique of deuteration and tritiation of polarized double bonds, such as carbonyl compounds, yielding labeled alcohols of high specific activities. This one-pot synthesis uses carrier-free hydrogen gas in situ activated by a freshly prepared frustrated Lewis pair, generating reducing reagents. This labeling strategy shows better selectivity and functional group tolerances compared with current reductive methods. Reported is an example of the selective reduction of the aldehyde moiety of 3-acetylbenzaldehyde. What makes this technology groundbreaking is its mildness, selectivity, and generation of limited amount of radioactive waste as almost no byproducts were generated after use of (B(C6 F5 )3 3 H)(3 HTMP) reducing reagent. Radiochemical purity of desired 3 H-labeled product in a crude reaction mixture was determined of over 94%. This work provides, to the community of radiochemists, a practical protocol for frustrated Lewis pairs (FLP)-assisted deuterium/tritium labeling technology.
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Affiliation(s)
- Sabina Doubková
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Prague, Czech Republic
| | - Aleš Marek
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Prague, Czech Republic
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Kim Y, Liu LL, Stephan DW. N-Heterocyclic Carbene Derived 3-Azabutadiene as a π-Base in Classic and Frustrated Lewis Pair Chemistry. Chemistry 2019; 25:7110-7113. [PMID: 30968983 DOI: 10.1002/chem.201901609] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Indexed: 11/05/2022]
Abstract
N-Heterocyclic carbene (NHC) derived 3-azabutadienes 1 and 2 have been prepared by a single-step reaction of the corresponding NHC with cyclohexyl isocyanide. Compound 1 features π-basic, delocalized nucleophilic sites over the 3-azabutadiene moiety, therefore allowing for coordinating with small Lewis acids, such as AlCl3 , GaCl3 , and Me2 SAuCl, to form diverse classic Lewis adducts 3-5. Combination of 1 with B(C6 F5 )3 or [Ph3 C][B(C6 F5 )4 ] resulted in single-electron transfer and the obtained radical cation was detected by EPR. In addition, a frustrated Lewis pair comprised of the π-basic 1 and BPh3 effects the splitting of the O-H bond of phenol and the N-H bond of imidazole to give 7 and 8, respectively. An intrinsic bond orbital (IBO) analysis of the pathway leading to 8 showcases the transformation of the delocalized π-electrons of 1 to a newly formed C-H localized σ-bond.
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Affiliation(s)
- Youngsuk Kim
- Department of Chemistry, University of Toronto, 80 St. George St. Toronto, Ontario, M5S3H6, Canada.,Department of Chemistry, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Liu Leo Liu
- Department of Chemistry, University of Toronto, 80 St. George St. Toronto, Ontario, M5S3H6, Canada
| | - Douglas W Stephan
- Department of Chemistry, University of Toronto, 80 St. George St. Toronto, Ontario, M5S3H6, Canada
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