1
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Xiang L, Wang J, Matler A, Ye Q. Structure-constraint induced increase in Lewis acidity of tris( ortho-carboranyl)borane and selective complexation with Bestmann ylides. Chem Sci 2024:d4sc06144f. [PMID: 39397822 PMCID: PMC11465496 DOI: 10.1039/d4sc06144f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2024] [Accepted: 10/02/2024] [Indexed: 10/15/2024] Open
Abstract
The Lewis acidity of tris(ortho-carboranyl)borane has been slightly increased by mimicking the structural evolution from triarylborane to 9-aryl-9-borafluorene. The o-carborane-based analogue (C2B10H10)2B(C2B10H11), obtained via salt elimination between LiC2B10H11 and (C2B10H10)2BBr, has been fully characterized. Gutmann-Beckett and computational fluoride/hydride ion affinity (FIA/HIA) studies have confirmed the increase in Lewis acidity, which is attributable to structural constraint imposed by the CC-coupling between two carboranyl groups. Selective complexation of (C2B10H10)2B(C2B10H11) with Bestmann ylides R3PCCO (R = Ph, Cy) has been achieved, enabling further conversion into the zwitterionic phospholium salt through NHC-catalyzed proton transfer.
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Affiliation(s)
- Libo Xiang
- 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
| | - Junyi Wang
- Department of Chemistry, Southern University of Science and Technology 518055 Shenzhen P. R. China
| | - Alexander Matler
- 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
| | - Qing Ye
- 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
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2
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Pei R, Chang W, He L, Wang T, Zhao Y, Liang Y, Wang X. Main-group compounds selectively activate natural gas alkanes under room temperature and atmospheric pressure. Nat Commun 2024; 15:7943. [PMID: 39261473 PMCID: PMC11391052 DOI: 10.1038/s41467-024-52185-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 08/26/2024] [Indexed: 09/13/2024] Open
Abstract
Most C-H bond activations of natural gas alkanes rely on transition metal complexes. Activations by using main-group systems have been reported but required heating or photo-irradiation under high atmospheric pressure with rather low regioselectivity. Here we report that Lewis acid-carbene adducts facilely undergo oxidative additions to C-H bonds of ethane, propane and n-butane with high selectivity under room temperature and atmospheric pressure. The Lewis acids can be moved by the addition of a base and the carbene-derived products can be easily converted into aldehydes. This work offers a route for main-group element compounds to selectively functionalise C-H bonds of natural gas alkanes and other small molecules.
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Affiliation(s)
- Runbo Pei
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
- State Key laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
| | - Wenju Chang
- College of Chemistry, Fuzhou University, Fuzhou, China
| | - Liancheng He
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
- State Key laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
| | - Tao Wang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Yue Zhao
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Yong Liang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.
- Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Center, Nanjing University, Nanjing, China.
| | - Xinping Wang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.
- State Key laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China.
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3
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Ma W, Wang Y, Xue Y, Wang M, Lu C, Guo W, Liu YH, Shu D, Shao G, Xu Q, Tu D, Yan H. Molecular engineering of AIE-active boron clustoluminogens for enhanced boron neutron capture therapy. Chem Sci 2024; 15:4019-4030. [PMID: 38487248 PMCID: PMC10935674 DOI: 10.1039/d3sc06222h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 02/01/2024] [Indexed: 03/17/2024] Open
Abstract
The development of boron delivery agents bearing an imaging capability is crucial for boron neutron capture therapy (BNCT), yet it has been rarely explored. Here we present a new type of boron delivery agent that integrates aggregation-induced emission (AIE)-active imaging and a carborane cluster for the first time. In doing so, the new boron delivery agents have been rationally designed by incorporating a high boron content unit of a carborane cluster, an erlotinib targeting unit towards lung cancer cells, and a donor-acceptor type AIE unit bearing naphthalimide. The new boron delivery agents demonstrate both excellent AIE properties for imaging purposes and highly selective accumulation in tumors. For example, at a boron delivery agent dose of 15 mg kg-1, the boron amount reaches over 20 μg g-1, and both tumor/blood (T/B) and tumor/normal cell (T/N) ratios reach 20-30 times higher than those required by BNCT. The neutron irradiation experiments demonstrate highly efficient tumor growth suppression without any observable physical tissue damage and abnormal behavior in vivo. This study not only expands the application scopes of both AIE-active molecules and boron clusters, but also provides a new molecular engineering strategy for a deep-penetrating cancer therapeutic protocol based on BNCT.
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Affiliation(s)
- Wenli Ma
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Yanyang Wang
- Department of Nuclear Medicine, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University Nanjing 210008 China
| | - Yilin Xue
- Department of Nuclear Medicine, Nanjing First Hospital, Nanjing Medical University Nanjing 210033 China
| | - Mengmeng Wang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Changsheng Lu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Wanhua Guo
- Department of Nuclear Medicine, Nanjing Tongren Hospital, the Affiliated Hospital of Southeast University Medical School Nanjing 210033 China
| | - Yuan-Hao Liu
- Neuboron Therapy System Ltd. Xiamen 361028 China
- Nanjing University of Aeronautics and Astronautics Nanjing 210016 China
- Neuboron Medtech Ltd. Nanjing 211112 China
| | - Diyun Shu
- Neuboron Therapy System Ltd. Xiamen 361028 China
- Nanjing University of Aeronautics and Astronautics Nanjing 210016 China
- Neuboron Medtech Ltd. Nanjing 211112 China
| | - Guoqiang Shao
- Department of Nuclear Medicine, Nanjing First Hospital, Nanjing Medical University Nanjing 210033 China
| | - Qinfeng Xu
- Department of Nuclear Medicine, Jiangsu Province Hospital of Chinese Medicine, Affiliated Hospital of Nanjing University of Chinese Medicine Nanjing 210029 China
| | - Deshuang Tu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Hong Yan
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
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4
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Ju S, Zhang C, Tang B, Liu LL, Stephan DW, Wu Y. The Lewis superacidic aluminium cation: [(NHC)Al(C 6F 5) 2] . Chem Commun (Camb) 2024; 60:698-701. [PMID: 38111304 DOI: 10.1039/d3cc05440c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
The aluminium salt [(NHC)Al(tol)(C6F5)2][B(C6F5)4], (NHC = C3H2(N(iPr2C6H3))2) is shown to behave as a Lewis superacid as it abstracts fluoride from [SbF6]-. It also acts as a Lewis acid catalyst for hydrosilyation, hydrodefluorination and Friedel-Crafts reactions.
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Affiliation(s)
- Shaoying Ju
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China.
| | - Chi Zhang
- Department of Chemistry, Shenzhen Grubbs Institute and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China
| | - Beili Tang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China.
| | - Liu Leo Liu
- Department of Chemistry, Shenzhen Grubbs Institute and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China
| | - Douglas W Stephan
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China.
- Department of Chemistry, University of Toronto, Toronto, 80 St. George Street, Ontario M5S 3H6, Canada.
| | - Yile Wu
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China.
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5
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Wang T, Wang ZJ, Wang M, Wu L, Fang X, Liang Y, Lv J, Shi Z. Metal-Free Stereoconvergent C-H Borylation of Enamides. Angew Chem Int Ed Engl 2023; 62:e202313205. [PMID: 37721200 DOI: 10.1002/anie.202313205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/19/2023]
Abstract
Enamides, functional derivatives of enamines, play a significant role as synthetic targets. However, the stereoselective synthesis of these molecules has posed a longstanding challenge in organic chemistry, particularly for acyclic enamides that are less thermodynamically stable. In this study, we present a general strategy for constructing β-borylenamides by C-H borylation, which provides a versatile platform for generating the stereodefined enamides. Our approach involves the utilization of metalloid borenium cation, generated through the reaction of BBr3 and enamides in the presence of two different additives, avoiding any exogenous catalyst. Importantly, the stereoconvergent nature of this methodology allows for the use of starting materials with mixed E/Z configurations, thus highlighting the unique advantage of this chemistry. Mechanistic investigations have shed light on the pivotal roles played by the two additives, the reactive boron species, and the phenomenon of stereoconvergence.
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Affiliation(s)
- Tianhang Wang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Zheng-Jun Wang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210093, China
- Wenzhou Key Lab of Advanced Energy Storage and Conversion, Zhejiang Province Key Lab of Leather Engineering, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, Zhejiang, 325035, China
| | - Minyan Wang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Lei Wu
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Xiaowu Fang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Yong Liang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Jiahang Lv
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Zhuangzhi Shi
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu, 210093, China
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, 453007, China
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6
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Kumar Someswara Ashwathappa P, Higashi T, Desrosiers V, Omaña AA, Fontaine FG. Metal-Free Directed Site-Selective Csp 3 -H Borylation of Saturated Cyclic Amines. Angew Chem Int Ed Engl 2023; 62:e202309295. [PMID: 37535392 DOI: 10.1002/anie.202309295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/01/2023] [Accepted: 08/02/2023] [Indexed: 08/04/2023]
Abstract
The borylation of Csp3 -H bonds is a challenging transformation that is typically restricted to transition metal catalysis. Herein, we report the site-selective metal-free Csp3 -H borylation of saturated cyclic amines. It is possible to selectively borylate piperidine derivatives at the α or β positions according to the reaction conditions. The mechanism was supported by NMR spectroscopy, calorimetry experiments and density functional theory (DFT) computations. It suggests that the piperidine is dehydrogenated by complexation with BBr3 to produce an enamine intermediate, which is in turn borylated at either the α or β position according to the reaction conditions.
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Affiliation(s)
| | - Takuya Higashi
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Bunkyo-Ku, Tokyo 113-8656, Japan
| | - Vincent Desrosiers
- Département de Chimie, Université Laval, 1045 Avenue de la Médecine, Québec, Québec G1 V 0 A6, Canada
| | - Alvaro A Omaña
- Département de Chimie, Université Laval, 1045 Avenue de la Médecine, Québec, Québec G1 V 0 A6, Canada
| | - Frédéric-Georges Fontaine
- Département de Chimie, Université Laval, 1045 Avenue de la Médecine, Québec, Québec G1 V 0 A6, Canada
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7
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Lv W, Dai Y, Guo R, Su Y, Ruiz DA, Liu LL, Tung CH, Kong L. Geometrically Constrained Organoboron Species as Lewis Superacids and Organic Superbases. Angew Chem Int Ed Engl 2023; 62:e202308467. [PMID: 37395499 DOI: 10.1002/anie.202308467] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/03/2023] [Accepted: 07/03/2023] [Indexed: 07/04/2023]
Abstract
This report unveils an advancement in the formation of a Lewis superacid (LSA) and an organic superbase by the geometrical deformation of an organoboron species towards a T-shaped geometry. The boron dication [2]2+ supported by an amido diphosphine pincer ligand features both a large fluoride ion affinity (FIA>SbF5 ) and hydride ion affinity (HIA>B(C6 F5 )3 ), which qualifies it as both a hard and soft LSA. The unusual Lewis acidic properties of [2]2+ are further showcased by its ability to abstract hydride and fluoride from Et3 SiH and AgSbF6 respectively, and effectively catalyze the hydrodefluorination, defluorination/arylation, as well as reduction of carbonyl compounds. One and two-electron reduction of [2]2+ affords stable boron radical cation [2]⋅+ and borylene 2, respectively. The former species has an extremely high spin density of 0.798e at the boron atom, whereas the latter compound has been demonstrated to be a strong organic base (calcd. pKBH + (MeCN)=47.4) by both theoretical and experimental assessment. Overall, these results demonstrate the strong ability of geometric constraining to empower the central boron atom.
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Affiliation(s)
- Weiwei Lv
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, China
| | - Yuyang Dai
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, China
| | - Rui Guo
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, China
| | - Yuanting Su
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, China
| | - David A Ruiz
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Liu Leo Liu
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Chen-Ho Tung
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, China
| | - Lingbing Kong
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, China
- State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, China
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8
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Akram MO, Tidwell JR, Dutton JL, Martin CD. Bis(1-Methyl-ortho-Carboranyl)Borane. Angew Chem Int Ed Engl 2023; 62:e202307040. [PMID: 37338991 DOI: 10.1002/anie.202307040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 06/22/2023]
Abstract
The Lewis superacid, bis(1-methyl-ortho-carboranyl)borane, is rapidly accessed in two steps. It is a very effective hydroboration reagent capable of B-H addition to alkenes, alkynes, and cyclopropanes. To date, this is the first identified Lewis superacidic secondary borane and most reactive neutral hydroboration reagent.
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Affiliation(s)
- Manjur O Akram
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, TX, 76798, USA
| | - John R Tidwell
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, TX, 76798, USA
| | - Jason L Dutton
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Caleb D Martin
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, TX, 76798, USA
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9
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Lu W, Hensiek N, Saha K, Dewhurst RD, Härterich M, Pranckevicius C, Hagspiel S, Dietz M, Krummenacher I, Braunschweig H. Electron-Precise Dicationic Tetraboranes: Syntheses, Structures and Rearrangement to an Alkylidene Borate-Borenium Zwitterion and a 1,3-Azaborinine. Chemistry 2023; 29:e202300644. [PMID: 37272320 DOI: 10.1002/chem.202300644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 06/02/2023] [Accepted: 06/02/2023] [Indexed: 06/06/2023]
Abstract
Carbene-stabilized symmetrical and unsymmetrical dicationic tetraboranes, featuring an electron-precise tetraborane chain, were synthesized and fully characterized. Reactions of these tetraboranes with reductants/bases give rise to different outcomes according to the conditions employed, including: 1) reduction and rearrangement of the tetraborane chain to give a zwitterionic alkylidene borate-borenium species; 2) cleavage of the tetraborane chain to afford a 1,3-azaborinine; and 3) reduction of the supporting ligands to provide a diamino dipotassium salt. The zwitterionic alkylidene borate-borenium species can be viewed as an analogue of the base-stabilized diborenes. NMR spectroscopy and DFT calculations reveal a highly polarized B-B bond in the zwitterionic alkylidene borate-borenium, in which the formal oxidation states of the boron atoms can be considered as -1 and +2. These results suggest the considerable potential of tetraboranes as synthons for low-valent boron species.
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Affiliation(s)
- Wei Lu
- 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
- Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, P. R. China
| | - Nicola Hensiek
- 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
| | - Koushik Saha
- 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
| | - 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
| | - Marcel Härterich
- 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
| | - Conor Pranckevicius
- 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
| | - Stephan Hagspiel
- 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
| | - Maximilian Dietz
- 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
| | - Ivo Krummenacher
- 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
| | - 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
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10
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Ingleson MJ. Main Group Catalyzed Arene Borylation: Challenges and Opportunities. ACS Catal 2023; 13:7691-7697. [PMID: 37288098 PMCID: PMC10242676 DOI: 10.1021/acscatal.3c01668] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Indexed: 06/09/2023]
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11
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Ren H, Zhang P, Xu J, Ma W, Tu D, Lu CS, Yan H. Direct B-H Functionalization of Icosahedral Carboranes via Hydrogen Atom Transfer. J Am Chem Soc 2023; 145:7638-7647. [PMID: 36946888 DOI: 10.1021/jacs.3c01314] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
The efficient and selective functionalization of icosahedral carboranes (C2B10H12) at the boron vertexes is a long-standing challenge owing to the presence of 10 inert B-H bonds in a similar chemical environment. Herein, we report a new reaction paradigm for direct B-H functionalization of icosahedral carboranes via B-H homolysis enabled by a nitrogen-centered radical-mediated hydrogen atom transfer (HAT) strategy. Both the HAT process of the carborane B-H bond and the resulting boron-centered carboranyl radical intermediate have been confirmed experimentally. The reaction occurs at the most electron-rich boron vertex with the lowest B-H bond dissociation energy (BDE). Using this strategy, diverse carborane derivatization, including thiolation, selenation, alkynylation, alkenylation, cyanation, and halogenation, have been achieved in satisfactory yields under a photoinitiated condition in a metal-free and redox-neutral fashion. Moreover, the synthetic utility of the current protocol was also demonstrated by both the scale-up reaction and the construction of carborane-based functional molecules. Therefore, this methodology opens a radical pathway to carborane functionalization, which is distinct from the B-H heterolytic mechanism in the traditional strategies.
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Affiliation(s)
- Hongyuan Ren
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Ping Zhang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Jingkai Xu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Wenli Ma
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Deshuang Tu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Chang-Sheng Lu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Hong Yan
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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Mebs S, Beckmann J. In silico capture and activation of methane with light atom molecules. Phys Chem Chem Phys 2023; 25:5656-5662. [PMID: 36734164 DOI: 10.1039/d2cp05821a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Methane (CH4) can be captured in silico with a light atom molecule containing only C, H, Si, O, and B atoms, respectively. A tripodal peri-substituted ligand system was employed, namely, [(5-Ph2B-xan-4-)3Si]H (1, xan = xanthene), which after hydride abstraction (1+) carries four Lewis acidic sites within the cationic cage structure. In a previous study, this system was shown to be able to capture noble gas atoms He-Kr (Mebs & Beckmann 2022). In the corresponding methane complex, 1+CH4, a polarized Si+⋯CH4 contact of 2.289 Å as well as series of (H3)CH⋯O/CPh hydrogen bonds enforce spatial CH4 fixation (the molecule obeys C3-symmetry) and slight activation. A trigonal-pyramidal Si-CHeq3-Hax local geometry is thereby approached with Hax-C-Heq angles decreased to 103.7°. All attempts to replace the Lews acidic -BPh2 fragments in 1 with basic -PR2 (R = Ph, tBu) fragments indeed increased intra-molecular hydrogen bonding between host molecule and CH4, and thus caused stronger activation of the latter, however ultimately resulted in the formation of energetically favorable quenched structures with short P-Si contacts, making CH4 binding hard to achieve. The electronic situation of two hypothetic methane complexes, 1+CH4 and [(5-tBu2P-xan-4-)3SiCH4]+ (2+CH4), was determined by a set of calculated real-space bonding indicators (RSBIs) including the Atoms-In-Molecules (AIM), non-covalent interactions index (NCI), and electron localizability indicator (ELI-D) methods, highlighting crucial differences in the level of activation. The proposed ligand systems serve as blueprints for a more general structural design with adjustable trigonal ligand systems in which central atom, spacer fragment, and functional peri-partner can be varied to facilitate different chemical tasks.
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Affiliation(s)
- Stefan Mebs
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
| | - Jens Beckmann
- Institut für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Straße 7, 28359, Bremen, Germany
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Akram MO, Tidwell JR, Dutton JL, Martin CD. Tris(ortho-carboranyl)borane: An Isolable, Halogen-Free, Lewis Superacid. Angew Chem Int Ed Engl 2022; 61:e202212073. [PMID: 36135949 PMCID: PMC9828388 DOI: 10.1002/anie.202212073] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Indexed: 01/12/2023]
Abstract
The synthesis of tris(ortho-carboranyl)borane (BoCb3 ), a single site neutral Lewis superacid, in one pot from commercially available materials is achieved. The high fluoride ion affinity (FIA) confirms its classification as a Lewis superacid and the Gutmann-Beckett method as well as adducts with Lewis bases indicate stronger Lewis acidity over the widely used fluorinated aryl boranes. The electron withdrawing effect of ortho-carborane and lack of pi-delocalization of the LUMO rationalize the unusually high Lewis acidity. Catalytic studies indicate that BoCb3 is a superior catalyst for promoting C-F bond functionalization reactions than tris(pentafluorophenyl)borane [B(C6 F5 )3 ].
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Affiliation(s)
- Manjur O. Akram
- Department of Chemistry and BiochemistryBaylor UniversityOne Bear Place #97348WacoTX 76798USA
| | - John R. Tidwell
- Department of Chemistry and BiochemistryBaylor UniversityOne Bear Place #97348WacoTX 76798USA
| | - Jason L. Dutton
- Department of Biochemistry and ChemistryLa Trobe Institute for Molecular ScienceLa Trobe UniversityMelbourneVictoria3086Australia
| | - Caleb D. Martin
- Department of Chemistry and BiochemistryBaylor UniversityOne Bear Place #97348WacoTX 76798USA
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Hamdaoui M, Liu F, Cornaton Y, Lu X, Shi X, Zhang H, Liu J, Spingler B, Djukic JP, Duttwyler S. An Iridium-Stabilized Borenium Intermediate. J Am Chem Soc 2022; 144:18359-18374. [PMID: 36173688 DOI: 10.1021/jacs.2c06298] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Exploration of new organometallic systems based on polyhedral boron clusters has the potential to solve challenging chemical problems such as the stabilization of reactive intermediates and transition-state-like species postulated for E-H (E = H, B, C, Si) bond activation reactions. We report on facile and clean B-H activation of a hydroborane by a new iridium boron cluster complex. The product of this reaction is an unprecedented and fully characterized transition metal-stabilized boron cation or borenium. Moreover, this intermediate bears an unusual intramolecular B···H interaction between the hydrogen originating from the activated hydroborane and the cyclometallated metal-bonded boron atom of the boron cluster. This B···H interaction is proposed to be an arrested insertion of hydrogen into the Bcage-metal bond and the initiation step for iridium "cage-walking" around the upper surface of the boron cluster. The "cage-walking" process is supported by the hydrogen-deuterium exchange observed at the boron cluster, and a mechanism is proposed on the basis of theoretical methods with a special focus on the role of noncovalent interactions. All new compounds were isolated and fully characterized by NMR spectroscopy and elemental analysis. Key compounds were studied by single crystal X-ray diffraction and X-ray photoelectron spectroscopy.
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Affiliation(s)
- Mustapha Hamdaoui
- Department of Chemistry, Zheijang University, Hangzhou 310027, China
| | - Fan Liu
- Department of Chemistry, Zheijang University, Hangzhou 310027, China
| | - Yann Cornaton
- Laboratoire de Chimie et Systémique Organométalliques, Institut de Chimie de Strasbourg UMR 7177 CNRS, Université de Strasbourg, Strasbourg 67000, France
| | - Xingyu Lu
- Instrumentation Service Center for Molecular Sciences, Westlake University, Hangzhou 310024, China
| | - Xiaohuo Shi
- Instrumentation Service Center for Molecular Sciences, Westlake University, Hangzhou 310024, China
| | - Huan Zhang
- Instrumentation Service Center for Molecular Sciences, Westlake University, Hangzhou 310024, China
| | - Jiyong Liu
- Department of Chemistry, Zheijang University, Hangzhou 310027, China
| | - Bernhard Spingler
- Department of Chemistry, University of Zurich, Zurich 8057, Switzerland
| | - Jean-Pierre Djukic
- Laboratoire de Chimie et Systémique Organométalliques, Institut de Chimie de Strasbourg UMR 7177 CNRS, Université de Strasbourg, Strasbourg 67000, France
| | - Simon Duttwyler
- Department of Chemistry, Zheijang University, Hangzhou 310027, China
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Škoch K, Chen C, Daniliuc CG, Kehr G, Erker G. A deprotonation pathway to reactive [B]CH 2 boraalkenes. Dalton Trans 2022; 51:7695-7704. [PMID: 35521694 DOI: 10.1039/d2dt01193j] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The BH compounds IMes(ArF)BH(NTf2) (ArF: C6F5 or FpXyl) were converted to the IMes(ArF)BCH2 boraalkenes in a three step reaction sequence of B-methylation with methyllithium, hydride abstraction and deprotonation. The BCH2 boraalkenes reacted with elemental sulfur to give a thiaborirane product. They underwent [2+2] cycloaddition reactions with carbon dioxide or sulfur dioxide to give four-membered boron containing heterocycles. The boraalkenes added strongly Lewis acidic boranes at their CH2 carbon atoms. The corresponding HB(C6F5)2/boraalkene adduct reduced carbon monoxide to a -OCH(C6F5)- moiety inside a five-membered heterocycle at the B-CH2-B template. The boraalkenes reacted with the [(Me2S)AuCl] reagent to form the corresponding (boraalkene)AuCl complexes.
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Affiliation(s)
- Karel Škoch
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraβe 40, 48149 Münster, Germany.
| | - Chaohuang Chen
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraβe 40, 48149 Münster, Germany.
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraβe 40, 48149 Münster, Germany.
| | - Gerald Kehr
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraβe 40, 48149 Münster, Germany.
| | - Gerhard Erker
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraβe 40, 48149 Münster, Germany.
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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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Boron compounds for catalytic applications. ADVANCES IN CATALYSIS 2022. [DOI: 10.1016/bs.acat.2022.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Chen C, Daniliuc CG, Kehr G, Erker G. Formation and Cycloaddition Reactions of a Reactive Boraalkene Stabilized Internally by N-Heterocyclic Carbene. Angew Chem Int Ed Engl 2021; 60:19905-19911. [PMID: 34219331 DOI: 10.1002/anie.202106724] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/28/2021] [Indexed: 01/07/2023]
Abstract
The synthesis of element-carbon double bonds is of great importance for the development and understanding of reactive π-bonded systems in chemistry. The seven-membered heterocyclic system 4 b is readily made by internal C-H activation at a pendent isopropyl methyl group of the respective [(IPr)C6 F5 BH]+ borenium ion. Subsequent deprotonation with the IMes carbene gives the neutral cyclic boraalkene system 5 b. The B=C double bond in compound 5 b adds carbon dioxide, CS2 , sulfur dioxide, phenyl isocyanate, an acetylenic ester or two NO molecules to give the corresponding four-membered ring annulated heterocycles. With sulfur or selenium 5 b gives the respective three-membered ring systems. N2 O reacts with 5 b to give a mixture of the related oxaborirane 18 and a unique [B]OH containing diazoalkane product 19.
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Affiliation(s)
- Chaohuang Chen
- 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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Chen C, Daniliuc CG, Kehr G, Erker G. Formation and Cycloaddition Reactions of a Reactive Boraalkene Stabilized Internally by
N
‐Heterocyclic Carbene. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202106724] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Chaohuang Chen
- 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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22
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DuChane CM, Chen J. Harnessing the reactivity of borenium for methane activation. Chem 2021. [DOI: 10.1016/j.chempr.2021.06.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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