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Liu TT, Chen J, Chen XL, Ma L, Guan BT, Lin Z, Shi ZJ. Neutral Boryl Radicals in Mixed-Valent B (III) Br-B (II) Adducts. Chemistry 2023; 29:e202202634. [PMID: 36217568 DOI: 10.1002/chem.202202634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Indexed: 11/06/2022]
Abstract
The general strategies to stabilize a boryl radical involve single electron delocalization by π-system and the steric hinderance from bulky groups. Herein, a new class of boryl radicals is reported, with intramolecular mixed-valent B(III) Br-B(II) adducts ligated by a cyclic (alkyl)(amino)carbene (CAAC). The radicals feature a large spin density on the boron center, which is ascertained by EPR spectroscopy and DFT calculations. Structural and computational analyses revealed that the stability of radical species was assisted by the CAAC ligand and a weak but significant B(III)Br-B(II) interaction, suggesting a cooperative avenue for stabilization of boryl radicals. Two-electron reduction of these new boryl radicals provides C-H insertion products via a borylene intermediate.
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Affiliation(s)
- Tong-Tong Liu
- Department of Chemistry, Fudan University, Shanghai, 200438, P. R. China
| | - Jiaxin Chen
- Department of Chemistry, The Hong Kong University of Science and Technology Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Xin-Lei Chen
- Department of Chemistry, Fudan University, Shanghai, 200438, P. R. China
| | - Li Ma
- Department of Chemistry, Fudan University, Shanghai, 200438, P. R. China
| | - Bing-Tao Guan
- Department of Chemistry, Fudan University, Shanghai, 200438, P. R. China
| | - Zhenyang Lin
- Department of Chemistry, The Hong Kong University of Science and Technology Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Zhang-Jie Shi
- Department of Chemistry, Fudan University, Shanghai, 200438, P. R. China
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Li Y, Zhu J. Mechanistic Insight into the Ni-Catalyzed Kumada Cross-Coupling: Alkylmagnesium Halide Promotes C-F Bond Activation and Electron-Deficient Metal Center Slows Down β-H Elimination. J Org Chem 2022; 87:8902-8909. [PMID: 35762620 DOI: 10.1021/acs.joc.2c00586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Ni-catalyzed Kumada-Tamao-Corriu (KTC) cross-coupling between aryl fluorides and alkyl Grignard reagents has been used to achieve a highly selective Csp2-Csp3 bond construction via the carbon-fluorine (C-F) bond activation. However, the detailed mechanism of this groundbreaking KTC reaction remains unclear. Herein, we perform a series of analyses by density functional theory (DFT) calculations in order to understand the reaction mechanisms for the selective activation of a highly inert C-F bond by Ni catalysts with bidentate phosphorus ligands. An alternative mechanism for Ni/Mg bimetallic cooperation C-F bond cleavage instead of a traditional oxidative addition was proposed. The push-pull interaction in the transition state provided by the Ni center and the Lewis acid of the Mg cation smoothly breaks the C-F bond, supported by the significantly decreased activation energy from 30.9 to 4.6 kcal mol-1 and principal interacting orbital analysis. Owing to the elevated lowest unoccupied molecular orbital energy level and the electron-deficient metal center caused by the bidentate phosphorus ligand, the β-H elimination could be impeded, increasing the selectivity of KTC cross-coupling. Our DFT results rationally explain the experimental observations, which will be helpful for further development of KTC cross-coupling.
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Affiliation(s)
- Yuanyuan Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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3
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Zhou TP, Deng WH, Wu Y, Liao RZ. QM/MM Calculations Suggested Concerted O‒O Bond Cleavage and Substrate Oxidation by Nonheme Diiron Toluene/o‐xylene Monooxygenase. Chem Asian J 2022; 17:e202200490. [DOI: 10.1002/asia.202200490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/01/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Tai-Ping Zhou
- Huazhong University of Science and Technology School of chemistry and chemical engineering CHINA
| | - Wen-Hao Deng
- Huazhong University of Science and Technology School of chemistry and chemical engineering CHINA
| | - Yuzhou Wu
- Huazhong University of Science and Technology School of chemistry and chemical engineering CHINA
| | - Rong-Zhen Liao
- Huazhong University of Science and technology College of Chemistry and Chemical Engeneering Luoyulu 1037 430074 Wuhan CHINA
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Fantuzzi F, Jiao Y, Dewhurst RD, Weinhold F, Braunschweig H, Engels B. Can a Wanzlick-like equilibrium exist between dicoordinate borylenes and diborenes? Chem Sci 2022; 13:5118-5129. [PMID: 35655568 PMCID: PMC9093173 DOI: 10.1039/d1sc05988b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 03/03/2022] [Indexed: 12/23/2022] Open
Abstract
Boron chemistry has experienced tremendous progress in the last few decades, resulting in the isolation of a variety of compounds with remarkable electronic structures and properties. Some examples are the singly Lewis-base-stabilised borylenes, wherein boron has a formal oxidation state of +I, and their dimers featuring a boron-boron double bond, namely diborenes. However, no evidence of a Wanzlick-type equilibrium between borylenes and diborenes, which would open a valuable route to the latter compounds, has been found. In this work, we combine DFT, coupled-cluster, multireference methods, and natural bond orbital/natural resonance theory analyses to investigate the electronic, structural, and kinetic factors controlling the reactivity of the transient CAAC-stabilised cyanoborylene, which spontaneously cyclotetramerises into a butterfly-type, twelve-membered (BCN)4 ring, and the reasons why its dimerisation through the boron atoms is hampered. The computations are also extended to the NHC-stabilised borylene counterparts. We reveal that the borylene ground state multiplicity dictates the preference for self-stabilising cyclooligomerisation over boron-boron dimerisation. Our comparison between NHC- vs. CAAC-stabilised borylenes provides a convincing rationale for why the reduction of the former always gives diborenes while a range of other products is found for the latter. Our findings provide a theoretical background for the rational design of base-stabilised borylenes, which could pave the way for novel synthetic routes to diborenes or alternatively non-dimerising systems for small-molecule activation.
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Affiliation(s)
- Felipe Fantuzzi
- Institute for Physical and Theoretical Chemistry, Julius-Maximilians-Universität Würzburg Emil-Fischer-Str. 42 97074 Würzburg Germany
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- School of Physical Sciences, Ingram Building, University of Kent Park Wood Road Canterbury CT2 7NH UK
| | - Yinchun Jiao
- Key Laboratory of Theoretical Organic Chemistry and Functional Molecules, Hunan University of Science and Technology Xiangtan 411201 China
| | - Rian D Dewhurst
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Frank Weinhold
- Theoretical Chemistry Institute and Department of Chemistry, University of Wisconsin-Madison Madison WI 53706 USA
| | - Holger Braunschweig
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Bernd Engels
- Institute for Physical and Theoretical Chemistry, Julius-Maximilians-Universität Würzburg Emil-Fischer-Str. 42 97074 Würzburg Germany
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You F, Zeng J, Rouf AM, Dong S, Zhu J. Theoretical Study on Reaction Mechanisms of Dinitrogen Activation and Coupling by Carbene-Stabilized Borylenes in Comparison with Intramolecular C-H Bond Activation. Chem Asian J 2022; 17:e202200232. [PMID: 35452168 DOI: 10.1002/asia.202200232] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/21/2022] [Indexed: 11/06/2022]
Abstract
Dinitrogen (N 2 ) activation is particularly challenging due to the significantly strong N≡N bond, let alone the catenation of two N 2 molecules. Recent experimental study shows that cyclic (alkyl)(amino)carbene (CAAC)-stabilized borylenes are able to tackle N 2 activation and coupling below room temperature. Here we carry out density functional theory calculations to explore the corresponding reaction mechanisms. The results indicate that the reaction barrier for the dinitrogen activation by the first borylene is slightly higher than that by the second borylene. In addition, replacing the CAAC moiety of the borylenes with cyclic diaminocarbenes (CDACs) could make such dinitrogen activation and coupling more favorable thermodynamically. The reaction mechanisms of the intramolecular C-H bond activation of borylene have also been discussed, which is found to be favorable both thermodynamically and kinetically in comparison with N 2 activation. Thus, adequate attention should be paid to the design of borylenes aiming at N 2 activation. In addition, our calculations suggest that the CDAC moiety of the borylene could lead to a different product in terms of intramolecular C-H bond activation. All these findings could be useful for the development of dinitrogen activation as well as C-H bond activation by main group species.
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Affiliation(s)
| | - Jie Zeng
- Xiamen University, Chemistry, CHINA
| | | | | | - Jun Zhu
- Xiamen University, Department of Chemistry, No. 422, South Siming Road, 361005, Xiamen, CHINA
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6
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Ghosh B, Cabrera-Trujillo JJ, Fernández I, Phukan AK. Stable N-heterocyclic borylenes with promising ligand properties: a contribution from theory. Inorg Chem Front 2022. [DOI: 10.1039/d2qi01511k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
DFT calculations reveal the power of ylides in stabilizing neutral singlet cyclic borylenes that are found to be capable of activating a variety of small molecules having enthalpically strong bonds.
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Affiliation(s)
- Bijoy Ghosh
- Department of Chemical Sciences, Tezpur University, Napam 784028, Assam, India
| | - Jorge Juan Cabrera-Trujillo
- Departamento de Química Orgánica I and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040-Madrid, Spain
| | - Israel Fernández
- Departamento de Química Orgánica I and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040-Madrid, Spain
| | - Ashwini K. Phukan
- Department of Chemical Sciences, Tezpur University, Napam 784028, Assam, India
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Czernetzki C, Arrowsmith M, Fantuzzi F, Gärtner A, Tröster T, Krummenacher I, Schorr F, Braunschweig H. A Neutral Beryllium(I) Radical. Angew Chem Int Ed Engl 2021; 60:20776-20780. [PMID: 34263524 PMCID: PMC8518760 DOI: 10.1002/anie.202108405] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Indexed: 01/07/2023]
Abstract
The reduction of a cyclic alkyl(amino)carbene (CAAC)-stabilized organoberyllium chloride yields the first neutral beryllium radical, which was characterized by EPR, IR, and UV/Vis spectroscopy, X-ray crystallography, and DFT calculations.
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Affiliation(s)
- Corinna Czernetzki
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Merle Arrowsmith
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Felipe Fantuzzi
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Annalena Gärtner
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Tobias Tröster
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Ivo Krummenacher
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Fabian Schorr
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Holger Braunschweig
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
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8
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Czernetzki C, Arrowsmith M, Fantuzzi F, Gärtner A, Tröster T, Krummenacher I, Schorr F, Braunschweig H. Ein neutrales Beryllium(I)‐Radikal. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202108405] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Corinna Czernetzki
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Merle Arrowsmith
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Felipe Fantuzzi
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Annalena Gärtner
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Tobias Tröster
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Ivo Krummenacher
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Fabian Schorr
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Holger Braunschweig
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
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