1
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Dhara D, Endres L, Krummenacher I, Arrowsmith M, Dewhurst RD, Engels B, Bertermann R, Finze M, Demeshko S, Meyer F, Fantuzzi F, Braunschweig H. Synthesis and Reactivity of a Dialane-Bridged Diradical. Angew Chem Int Ed Engl 2024; 63:e202401052. [PMID: 38415886 DOI: 10.1002/anie.202401052] [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: 01/16/2024] [Revised: 02/07/2024] [Accepted: 02/09/2024] [Indexed: 02/29/2024]
Abstract
Radicals of the lightest group 13 element, boron, are well established and observed in numerous forms. In contrast to boron, radical chemistry involving the heavier group 13 elements (aluminum, gallium, indium, and thallium) remains largely underexplored, primarily attributed to the formidable synthetic challenges associated with these elements. Herein, we report the synthesis and isolation of planar and twisted conformers of a doubly CAAC (cyclic alkyl(amino)carbene)-radical-substituted dialane. Extensive characterization through spectroscopic analyses and X-ray crystallography confirms their identity, while quantum chemical calculations support their open-shell nature and provide further insights into their electronic structures. The dialane-connected diradicals exhibit high susceptibility to oxidation, as evidenced by electrochemical measurements and reactions with o-chloranil and a variety of organic azides. This study opens a previously uncharted class of dialuminum systems to study, broadening the scope of diradical chemistry and its potential applications.
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Affiliation(s)
- Debabrata Dhara
- 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
| | - Lukas Endres
- 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
- Institute for Physical and Theoretical Chemistry Julius-Maximilians-Universität Würzburg, Emil-Fischer-Str. 42, 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
| | - Merle Arrowsmith
- 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
| | - Bernd Engels
- Institute for Physical and Theoretical Chemistry Julius-Maximilians-Universität Würzburg, Emil-Fischer-Str. 42, 97074, Würzburg, Germany
| | - Rüdiger Bertermann
- 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
| | - Maik Finze
- 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
| | - Serhiy Demeshko
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstraße 4, 37077, Göttingen, Germany
| | - Franc Meyer
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstraße 4, 37077, Göttingen, Germany
| | - Felipe Fantuzzi
- School of Chemistry and Forensic Science, University of Kent, Canterbury, Park Wood Rd, CT2 7NH, United Kingdom
| | - 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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2
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Mao X, Qiu S, Guo R, Dai Y, Zhang J, Kong L, Xie Z. Cyclic (Alkyl)(Amino)Carbene-Iminoboryl Compounds with Three Formal Oxidation States. J Am Chem Soc 2024; 146:10917-10924. [PMID: 38587904 DOI: 10.1021/jacs.4c01934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
BN/CC isosterism is an effective strategy to build hybrid functional molecules with unique properties. In contrast to the alkynyl iminium salts derived from cyclic (alkyl)(amino)carbenes (CAACs) that feature only one reversible reduction wave, the isoelectronic cationic CAAC-iminoboryl adducts could be singly and doubly reduced smoothly. Both the resultant neutral radical and anionic azaborataallenes bear NBC-mixed allenic structures. The former radical has a high spin-density of 0.55e at CCAAC carbon, yet exhibits formal boron-centered radical reactivity. The latter azaborataallenes feature the nucleophilic CCAAC center and polar N(δ-)═B(δ+)═C(δ-) unit, and readily undergo nucleophilic substitution, isocyanide insertion, dipolar addition and cycloaddition reactions etc. The N-substituents have been shown to have a significant influence on the solid-state structure, thermal stability, and reactivity of azaborataallenes. This work showcases the allenic BN-unsaturated species as versatile building blocks in organic synthesis.
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Affiliation(s)
- Xiaofeng Mao
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong 999077, China
| | - Shuang Qiu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Rui Guo
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Yuyang Dai
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Jie Zhang
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong 999077, China
| | - Lingbing Kong
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Zuowei Xie
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong 999077, China
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
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3
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Heinz M, Arrowsmith M, Schweizer JI, Krummenacher I, Holthausen MC, Braunschweig H. Experimental and Computational Study of a Confirmed Borylene-to-Diborene Dimerization. J Am Chem Soc 2023; 145:22685-22696. [PMID: 37802099 DOI: 10.1021/jacs.3c07979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/08/2023]
Abstract
While the dimerization of heavier group 13 carbene analogues to the corresponding alkene analogues is known and relatively well understood, the dimerization of dicoordinate borylenes (LRB:, L = neutral donor; R = anionic substituent) to the corresponding diborenes (LRB═BRL) has never been directly observed. In this study we present the first example of a formal borylene-to-diborene dimerization through abstraction of a labile phosphine ligand from the tricoordinate hydroborylene precursor (CAAC)(Me3P)BH (CAAC = cyclic alkyl(amino)carbene) by bulky Lewis-acidic dihaloboranes (BX2Y, X = Cl, Br, Y = aryl, boryl), generating the corresponding dihydrodiborene (CAAC)HB═BH(CAAC) and (Me3P)BX2Y as the byproduct. An in-depth experimental and computational mechanistic analysis shows that this seemingly simple process (2 LL'BH + 2 BX2Y → LHB═BHL + 2 L'BX2Y) is in fact based on a complex sequence of finely tuned processes, involving the one-electron oxidation of and PMe3 abstraction from the borylene precursor by BX2Y, multiple halide transfers between (di)boron intermediates and BX2Y/[BX3Y]-, and multiple one-electron redox processes between diboron intermediates and the borylene precursor, which make the reaction ultimately autocatalytic in [(CAAC)(Me3P)BH]•+. The findings suggest that [LBXR]• boryl radicals are more likely coupling partners than dicoordinate LRB: borylenes in the reductive coupling of base-stabilized LBX2R boranes to LRB═BRL diborenes.
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Affiliation(s)
- Myron Heinz
- Institute for Inorganic and Analytical Chemistry, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Merle Arrowsmith
- 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
| | - Julia I Schweizer
- Institute for Inorganic and Analytical Chemistry, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, 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
| | - Max C Holthausen
- Institute for Inorganic and Analytical Chemistry, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, 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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4
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Gärtner A, Meier L, Arrowsmith M, Dietz M, Krummenacher I, Bertermann R, Fantuzzi F, Braunschweig H. Highly Strained Arene-Fused 1,2-Diborete Biradicaloid. J Am Chem Soc 2022; 144:21363-21370. [DOI: 10.1021/jacs.2c09971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Annalena Gärtner
- 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
| | - Lukas Meier
- 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
| | - Merle Arrowsmith
- 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
| | - Rüdiger Bertermann
- 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
| | - Felipe Fantuzzi
- School of Chemistry and Forensic Science, University of Kent, CT2 7NH Canterbury, U.K
| | - 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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5
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Stoy A, Härterich M, Dewhurst RD, Jiménez-Halla JOC, Endres P, Eyßelein M, Kupfer T, Deissenberger A, Thiess T, Braunschweig H. Evidence for Borylene Carbonyl (LHB═C═O) and Base-Stabilized (LHB═O) and Base-Free Oxoborane (RB≡O) Intermediates in the Reactions of Diborenes with CO 2. J Am Chem Soc 2022; 144:3376-3380. [PMID: 35179031 DOI: 10.1021/jacs.2c00479] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Doubly N-heterocyclic-carbene-stabilized diborenes undergo facile reactions with CO2, initially providing dibora-β-lactones. These lactones convert over time to their 2,4-diboraoxetan-3-one isomers through a presumed dissociative pathway and hypovalent boron species borylene carbonyls (LHB═C═O) and base-stabilized oxoboranes (LHB═O). Repeating these reactions with doubly cyclic(alkyl)(amino)carbene-stabilized diborenes allowed the isolation of a borylene carbonyl intermediate, whereas a base-stabilized oxoborane could be inferred by the isolation of a boroxine from the reaction mixture. These results, supported by calculations, confirm the presumed mechanism of the diboralactone-to-diboraoxetanone isomerization while also establishing a surprising level of stability for three unknown or very rare hypovalent boron species: base-stabilized derivatives of the parent borylene carbonyl (LHB═C═O) and parent oxoborane (LHB═O) as well as base-free oxoboranes (RB≡O).
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Affiliation(s)
- Andreas Stoy
- 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
| | - 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
| | - J Oscar C Jiménez-Halla
- Department of Chemistry, Division of Natural and Exact Sciences, University of Guanajuato, Campus Gto, Noria Alta s/n, 36050 Guanajuato, Mexico
| | - Peter Endres
- 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 Eyßelein
- 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
| | - Thomas Kupfer
- 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
| | - Andrea Deissenberger
- 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
| | - Torsten Thiess
- 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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6
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Lu W, Jayaraman A, Fantuzzi F, Dewhurst RD, Härterich M, Dietz M, Hagspiel S, Krummenacher I, Hammond K, Cui J, Braunschweig H. Ein unsymmetrisches, cyclisches Diboren basierend auf einem chelatisierenden CAAC‐Liganden sowie dessen Aktivierung kleiner Moleküle und Umlagerungsreaktionen. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202113947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Wei Lu
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Key Laboratory of Green Chemistry & Technology of Ministry of Education College of Chemistry Sichuan University 29 Wangjiang Road Chengdu 610064 P. R. China
| | - Arumugam Jayaraman
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Felipe Fantuzzi
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- School of Physical Sciences Ingram Building University of Kent Park Wood Road Canterbury CT2 7NH United Kingdom
| | - Rian D. Dewhurst
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Marcel Härterich
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Maximilian Dietz
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Stephan Hagspiel
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Ivo Krummenacher
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Kai Hammond
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Jingjing Cui
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Holger Braunschweig
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
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7
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Roesky HW, Kushvaha SK, Mishra A, Mondal KC. Recent advances in the domain of Cyclic (alkyl)(amino) carbenes. Chem Asian J 2022; 17:e202101301. [PMID: 34989475 PMCID: PMC9307053 DOI: 10.1002/asia.202101301] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/25/2021] [Indexed: 12/03/2022]
Abstract
Isolation of cyclic (alkyl) amino carbenes (cAACs) in 2005 has been a major achievement in the field of stable carbenes due to their better electronic properties. cAACs and bicyclic(alkyl)(amino)carbene (BicAAC) in essence are the most electrophilic as well as nucleophilic carbenes are known till date. Due to their excellent electronic properties in terms of nucleophilic and electrophilic character, cAACs have been utilized in different areas of chemistry, including stabilization of low valent main group and transition metal species, activation of small molecules, and catalysis. The applications of cAACs in catalysis have opened up new avenues of research in the field of cAAC chemistry. This review summarizes the major results of cAAC chemistry published until August 2021.
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Affiliation(s)
- Herbert W Roesky
- Georg-August-Universitat Gottingen, Department of Chemistry, Tammannstrasse 4, 37077, Göttingen, GERMANY
| | | | - Ankush Mishra
- IIT Madras: Indian Institute of Technology Madras, Chemistry, INDIA
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8
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Lu W, Jayaraman A, Fantuzzi F, Dewhurst RD, Härterich M, Dietz M, Hagspiel S, Krummenacher I, Hammond K, Cui J, Braunschweig H. An Unsymmetrical, Cyclic Diborene Based on a Chelating CAAC Ligand and its Small-Molecule Activation and Rearrangement Chemistry. Angew Chem Int Ed Engl 2021; 61:e202113947. [PMID: 34750945 PMCID: PMC9299934 DOI: 10.1002/anie.202113947] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Indexed: 01/15/2023]
Abstract
A one‐pot synthesis of a CAAC‐stabilized, unsymmetrical, cyclic diborene was achieved via consecutive two‐electron reduction steps from an adduct of CAAC and B2Br4(SMe2)2. Theoretical studies revealed that this diborene has a considerably smaller HOMO–LUMO gap than those of reported NHC‐ and phosphine‐supported diborenes. Complexation of the diborene with [AuCl(PCy3)] afforded two diborene–AuI π complexes, while reaction with DurBH2, P4 and a terminal acetylene led to the cleavage of B−H, P−P, and C−C π bonds, respectively. Thermal rearrangement of the diborene gave an electron‐rich cyclic alkylideneborane, which readily coordinated to AgI via its B=C double bond.
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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
| | - Arumugam Jayaraman
- 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
| | - Felipe Fantuzzi
- 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, United Kingdom
| | - 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
| | - 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
| | - 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
| | - 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
| | - Kai Hammond
- 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
| | - Jingjing Cui
- 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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9
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Härterich M, Ritschel B, Arrowsmith M, Böhnke J, Krummenacher I, Phukan AK, Braunschweig H. Hybrid Inorganic-Organic Cross-Metathesis between Diborenes and Acetylene. J Am Chem Soc 2021; 143:18339-18345. [PMID: 34677063 DOI: 10.1021/jacs.1c10131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ruthenium-catalyzed cross-metathesis of alkenes and alkynes, which splits the alkene C═C double bond and couples one-half to each carbon of the alkyne C≡C triple bond, is one of the most efficient tools for the synthesis of 1,3-dienes, with wide-ranging applications, including pharmaceutical and polymer chemistry. In contrast, inorganic main-group metathesis reactions are restricted to a handful of examples of heavier p-block multiple bonds (P═P, Ge═Ge, and E≡E, E = Ge, Sn, Pb). We now report the first examples of thermally induced, transition-metal-free cross-metathesis between an organic alkyne and inorganic cyclic alkyl(amino)carbene (CAAC)-stabilized B═B double bonds, which yield fully planar, π-delocalized 1,8-diaza-3,6-diboraoctatetraenes. Density functional theory studies show that these compounds have an open-shell singlet biradical ground state with a thermally accessible closed-shell state. In-depth computational mechanistic analyses show that they are formed via a biradical cycloaddition-cycloreversion mechanism. Finally, unlike their organic counterparts, these B,N-analogues of octatetraene can undergo two-electron chemical reduction to form diamagnetic dianions.
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Affiliation(s)
- Marcel Härterich
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany
| | - Benedikt Ritschel
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany
| | - Merle Arrowsmith
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany
| | - Julian Böhnke
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany
| | - Ivo Krummenacher
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany
| | - Ashwini K Phukan
- Department of Chemical Sciences, Tezpur University, Tezpur 784028, Assam, India
| | - Holger Braunschweig
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany.,Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany
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10
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Arrowsmith M, Endres S, Heinz M, Nestler V, Holthausen MC, Braunschweig H. Probing the Boundaries between Lewis-Basic and Redox Behavior of a Parent Borylene. Chemistry 2021; 27:17660-17668. [PMID: 34596278 PMCID: PMC9299150 DOI: 10.1002/chem.202103256] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Indexed: 11/09/2022]
Abstract
The parent borylene (CAAC)(Me3P)BH, 1 (CAAC=cyclic alkyl(amino)carbene), acts both as a Lewis base and one‐electron reducing agent towards group 13 trichlorides (ECl3, E=B, Al, Ga, In), yielding the adducts 1‐ECl3 and increasing proportions of the radical cation [1]•+ for the heavier group 13 analogues. With boron trihalides (BX3, X=F, Cl, Br, I) 1 undergoes sequential adduct formation and halide abstraction reactions to yield borylboronium cations and shows an increasing tendency towards redox processes for the heavier halides. Calculations confirm that 1 acts as a strong Lewis base towards EX3 and show a marked increase in the B−E bond dissociation energies down both group 13 and the halide group.
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Affiliation(s)
- Merle Arrowsmith
- 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
| | - Sara Endres
- 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
| | - Myron Heinz
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, Max-von-Laue-Str. 7, 60438, Frankfurt am Main, Germany
| | - Vincent Nestler
- 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
| | - Max C Holthausen
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, Max-von-Laue-Str. 7, 60438, Frankfurt am Main, 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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11
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Xu B, Beckers H, Ye H, Lu Y, Cheng J, Wang X, Riedel S. Cleavage of the N≡N Triple Bond and Unpredicted Formation of the Cyclic 1,3‐Diaza‐2,4‐Diborete (FB)
2
N
2
from N
2
and Fluoroborylene BF. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202106984] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Bing Xu
- School of Chemical Science and Engineering Department Shanghai Key lab of Chemical Assessment and Sustainability Tongji University Shanghai 200092 China
- Institut für Chemie und Biochemie – Anorganische Chemie Freie Universität Berlin Fabeckstrasse 34–36 14195 Berlin Germany
| | - Helmut Beckers
- Institut für Chemie und Biochemie – Anorganische Chemie Freie Universität Berlin Fabeckstrasse 34–36 14195 Berlin Germany
| | - Haoyu Ye
- School of Chemical Science and Engineering Department Shanghai Key lab of Chemical Assessment and Sustainability Tongji University Shanghai 200092 China
| | - Yan Lu
- Institut für Chemie und Biochemie – Anorganische Chemie Freie Universität Berlin Fabeckstrasse 34–36 14195 Berlin Germany
| | - Juanjuan Cheng
- School of Chemical Science and Engineering Department Shanghai Key lab of Chemical Assessment and Sustainability Tongji University Shanghai 200092 China
| | - Xuefeng Wang
- School of Chemical Science and Engineering Department Shanghai Key lab of Chemical Assessment and Sustainability Tongji University Shanghai 200092 China
| | - Sebastian Riedel
- Institut für Chemie und Biochemie – Anorganische Chemie Freie Universität Berlin Fabeckstrasse 34–36 14195 Berlin Germany
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12
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Xu B, Beckers H, Ye H, Lu Y, Cheng J, Wang X, Riedel S. Cleavage of the N≡N Triple Bond and Unpredicted Formation of the Cyclic 1,3-Diaza-2,4-Diborete (FB) 2 N 2 from N 2 and Fluoroborylene BF. Angew Chem Int Ed Engl 2021; 60:17205-17210. [PMID: 34114317 PMCID: PMC8361949 DOI: 10.1002/anie.202106984] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Indexed: 12/13/2022]
Abstract
A complete cleavage of the triple bond of N2 by fluoroborylene (:BF) was achieved in a low-temperature N2 matrix by the formation of the four-membered heterocycle FB(μ-N)2 BF, which lacks a trans-annular N-N bond. Additionally, the linear complex FB=N-N=BF and cyclic FB(η2 -N2 ) were formed. These novel species were characterized by their matrix infrared spectra and quantum-chemical calculations. The puckered four-membered-ring B2 N2 complex shows a delocalized aromatic two-electron π-system in conjugation with the exo-cyclic fluorine π lone pairs. This work may contribute to a rational design of catalysts based on borylene for artificial dinitrogen activation.
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Affiliation(s)
- Bing Xu
- School of Chemical Science and Engineering DepartmentShanghai Key lab of Chemical Assessment and SustainabilityTongji UniversityShanghai200092China
- Institut für Chemie und Biochemie – Anorganische ChemieFreie Universität BerlinFabeckstrasse 34–3614195BerlinGermany
| | - Helmut Beckers
- Institut für Chemie und Biochemie – Anorganische ChemieFreie Universität BerlinFabeckstrasse 34–3614195BerlinGermany
| | - Haoyu Ye
- School of Chemical Science and Engineering DepartmentShanghai Key lab of Chemical Assessment and SustainabilityTongji UniversityShanghai200092China
| | - Yan Lu
- Institut für Chemie und Biochemie – Anorganische ChemieFreie Universität BerlinFabeckstrasse 34–3614195BerlinGermany
| | - Juanjuan Cheng
- School of Chemical Science and Engineering DepartmentShanghai Key lab of Chemical Assessment and SustainabilityTongji UniversityShanghai200092China
| | - Xuefeng Wang
- School of Chemical Science and Engineering DepartmentShanghai Key lab of Chemical Assessment and SustainabilityTongji UniversityShanghai200092China
| | - Sebastian Riedel
- Institut für Chemie und Biochemie – Anorganische ChemieFreie Universität BerlinFabeckstrasse 34–3614195BerlinGermany
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13
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Schmid P, Fantuzzi F, Klopf J, Schröder NB, Dewhurst RD, Braunschweig H, Engel V, Engels B. Twisting versus Delocalization in CAAC- and NHC-Stabilized Boron-Based Biradicals: The Roles of Sterics and Electronics. Chemistry 2021; 27:5160-5170. [PMID: 33225473 PMCID: PMC8048672 DOI: 10.1002/chem.202004619] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/12/2020] [Indexed: 11/06/2022]
Abstract
Twisted boron-based biradicals featuring unsaturated C2 R2 (R=Et, Me) bridges and stabilization by cyclic (alkyl)(amino)carbenes (CAACs) were recently prepared. These species show remarkable geometrical and electronic differences with respect to their unbridged counterparts. Herein, a thorough computational investigation on the origin of their distinct electrostructural properties is performed. It is shown that steric effects are mostly responsible for the preference for twisted over planar structures. The ground-state multiplicity of the twisted structure is modulated by the σ framework of the bridge, and different R groups lead to distinct multiplicities. In line with the experimental data, a planar structure driven by delocalization effects is observed as global minimum for R=H. The synthetic elusiveness of C2 R2 -bridged systems featuring N-heterocyclic carbenes (NHCs) was also investigated. These results could contribute to the engineering of novel main group biradicals.
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Affiliation(s)
- Paul Schmid
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Felipe Fantuzzi
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
- Institute for Inorganic ChemistryJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Jonas Klopf
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Niklas B. Schröder
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Rian D. Dewhurst
- 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
| | - Volker Engel
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Bernd Engels
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
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14
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Borthakur B, Ghosh B, Phukan AK. The flourishing chemistry of carbene stabilized compounds of group 13 and 14 elements. Polyhedron 2021. [DOI: 10.1016/j.poly.2021.115049] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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15
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Trose M, Cordes DB, Slawin AMZ, Stasch A. A Facile Synthesis of Robinson's NHC‐Stabilised Diborane(4). Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000596] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Michael Trose
- EaStCHEM School of Chemistry University of St Andrews North Haugh KY16 9ST St Andrews UK
| | - David B. Cordes
- EaStCHEM School of Chemistry University of St Andrews North Haugh KY16 9ST St Andrews UK
| | - Alexandra M. Z. Slawin
- EaStCHEM School of Chemistry University of St Andrews North Haugh KY16 9ST St Andrews UK
| | - Andreas Stasch
- EaStCHEM School of Chemistry University of St Andrews North Haugh KY16 9ST St Andrews UK
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16
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Saalfrank C, Fantuzzi F, Kupfer T, Ritschel B, Hammond K, Krummenacher I, Bertermann R, Wirthensohn R, Finze M, Schmid P, Engel V, Engels B, Braunschweig H. cAAC-Stabilized 9,10-diboraanthracenes-Acenes with Open-Shell Singlet Biradical Ground States. Angew Chem Int Ed Engl 2020; 59:19338-19343. [PMID: 32662218 PMCID: PMC7589216 DOI: 10.1002/anie.202008206] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Indexed: 12/19/2022]
Abstract
Narrow HOMO-LUMO gaps and high charge-carrier mobilities make larger acenes potentially high-efficient materials for organic electronic applications. The performance of such molecules was shown to significantly increase with increasing number of fused benzene rings. Bulk quantities, however, can only be obtained reliably for acenes up to heptacene. Theoretically, (oligo)acenes and (poly)acenes are predicted to have open-shell singlet biradical and polyradical ground states, respectively, for which experimental evidence is still scarce. We have now been able to dramatically lower the HOMO-LUMO gap of acenes without the necessity of unfavorable elongation of their conjugated π system, by incorporating two boron atoms into the anthracene skeleton. Stabilizing the boron centers with cyclic (alkyl)(amino)carbenes gives neutral 9,10-diboraanthracenes, which are shown to feature disjointed, open-shell singlet biradical ground states.
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Affiliation(s)
- Christian Saalfrank
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Felipe Fantuzzi
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institut für Physikalische und Theoretische ChemieJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Thomas Kupfer
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Benedikt Ritschel
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Kai Hammond
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Ivo Krummenacher
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Rüdiger Bertermann
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Raphael Wirthensohn
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Maik Finze
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Paul Schmid
- Institut für Physikalische und Theoretische ChemieJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Volker Engel
- Institut für Physikalische und Theoretische ChemieJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Bernd Engels
- Institut für Physikalische und Theoretische ChemieJulius-Maximilians-Universität WürzburgEmil-Fischer-Strasse 4297074WürzburgGermany
| | - Holger Braunschweig
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
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17
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One-pot, room-temperature conversion of dinitrogen to ammonium chloride at a main-group element. Nat Chem 2020; 12:1076-1080. [DOI: 10.1038/s41557-020-0520-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/01/2020] [Indexed: 11/09/2022]
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18
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Saalfrank C, Fantuzzi F, Kupfer T, Ritschel B, Hammond K, Krummenacher I, Bertermann R, Wirthensohn R, Finze M, Schmid P, Engel V, Engels B, Braunschweig H. cAAC‐stabilisierte 9,10‐Diboraanthracene – offenschalige Singulettbiradikale. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202008206] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Christian Saalfrank
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Felipe Fantuzzi
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Physikalische und Theoretische Chemie Julius-Maximilians-Universität Würzburg Emil-Fischer-Straße 42 97074 Würzburg Germany
| | - Thomas Kupfer
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Benedikt Ritschel
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Kai Hammond
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Ivo Krummenacher
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Rüdiger Bertermann
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Raphael Wirthensohn
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Maik Finze
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Paul Schmid
- Institut für Physikalische und Theoretische Chemie Julius-Maximilians-Universität Würzburg Emil-Fischer-Straße 42 97074 Würzburg Germany
| | - Volker Engel
- Institut für Physikalische und Theoretische Chemie Julius-Maximilians-Universität Würzburg Emil-Fischer-Straße 42 97074 Würzburg Germany
| | - Bernd Engels
- Institut für Physikalische und Theoretische Chemie Julius-Maximilians-Universität Würzburg Emil-Fischer-Straße 42 97074 Würzburg Germany
| | - Holger Braunschweig
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
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19
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Hagspiel S, Arrowsmith M, Fantuzzi F, Hermann A, Paprocki V, Drescher R, Krummenacher I, Braunschweig H. Reduction of a dihydroboryl cation to a boryl anion and its air-stable, neutral hydroboryl radical through hydrogen shuttling. Chem Sci 2020; 11:551-555. [PMID: 32206272 PMCID: PMC7069503 DOI: 10.1039/c9sc05026d] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 11/23/2019] [Indexed: 02/05/2023] Open
Abstract
The addition of Lewis bases to a cyclic (alkyl)(amino)carbene (CAAC)-supported dihydroboron triflate yields the mixed doubly base-stabilised dihydroboryl cations [(CAAC)BH2L]+. Of these, [(CAAC)2BH2]OTf (OTf = triflate) underwent facile two-electron reduction with KC8 owing to a 1,2-hydride migration from boron to the carbene carbon to yield a stable hydroboryl anion. One-electron oxidation of the latter yielded the first neutral hydroboryl radical, which is bench-stable in the solid state.
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Affiliation(s)
- Stephan Hagspiel
- Institut für Anorganische Chemie , 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
| | - Merle Arrowsmith
- Institut für Anorganische Chemie , 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
| | - Felipe Fantuzzi
- Institut für Anorganische Chemie , 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
- Institut für Physikalische und Theoretische Chemie , Julius-Maximilians-Universität Würzburg , Emil-Fischer-Straße 42 , 97074 Würzburg , Germany
| | - Alexander Hermann
- Institut für Anorganische Chemie , 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
| | - Valerie Paprocki
- Institut für Anorganische Chemie , 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
| | - Regina Drescher
- Institut für Anorganische Chemie , 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
- Institut für Anorganische Chemie , 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
- Institut für Anorganische Chemie , 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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20
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Schmidt U, Fantuzzi F, Arrowsmith M, Hermann A, Prieschl D, Rempel A, Engels B, Braunschweig H. Tuneable reduction of cymantrenylboranes to diborenes or borylene-derived boratafulvenes. Chem Commun (Camb) 2020; 56:14809-14812. [DOI: 10.1039/d0cc06398c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
By switching the reaction conditions, the reduction of a N-heterocyclic carbene-stabilised cymantrenyldibromoborane can be tuned to yield either the corresponding diborene or borylene, the latter being stabilised through a boratafulvene conformation.
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Affiliation(s)
- Uwe Schmidt
- Institute for Inorganic Chemistry
- Julius-Maximilians-Universität Würzburg
- Am Hubland
- Germany
- Institute for Sustainable Chemistry & Catalysis with Boron
| | - Felipe Fantuzzi
- Institute for Inorganic Chemistry
- Julius-Maximilians-Universität Würzburg
- Am Hubland
- Germany
- Institute for Sustainable Chemistry & Catalysis with Boron
| | - Merle Arrowsmith
- Institute for Inorganic Chemistry
- Julius-Maximilians-Universität Würzburg
- Am Hubland
- Germany
- Institute for Sustainable Chemistry & Catalysis with Boron
| | - Alexander Hermann
- Institute for Inorganic Chemistry
- Julius-Maximilians-Universität Würzburg
- Am Hubland
- Germany
- Institute for Sustainable Chemistry & Catalysis with Boron
| | - Dominic Prieschl
- Institute for Inorganic Chemistry
- Julius-Maximilians-Universität Würzburg
- Am Hubland
- Germany
- Institute for Sustainable Chemistry & Catalysis with Boron
| | - Anna Rempel
- Institute for Inorganic Chemistry
- Julius-Maximilians-Universität Würzburg
- Am Hubland
- Germany
- Institute for Sustainable Chemistry & Catalysis with Boron
| | - Bernd Engels
- Institute for Physical and Theoretical Chemistry
- Julius-Maximilians-Universität Würzburg
- 97074 Würzburg
- Germany
| | - Holger Braunschweig
- Institute for Inorganic Chemistry
- Julius-Maximilians-Universität Würzburg
- Am Hubland
- Germany
- Institute for Sustainable Chemistry & Catalysis with Boron
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21
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Manar KK, Porwal VK, Kamte RS, Adhikari M, Thakur SK, Bawari D, Choudhury AR, Singh S. Reactions of a BICAAC with hydroboranes: propensity for Lewis adduct formation and carbene insertion into the B-H bond. Dalton Trans 2019; 48:17472-17478. [PMID: 31714564 DOI: 10.1039/c9dt03382c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reactivity of a bicyclic (alkyl)(amino)carbene (BICAAC) towards different boranes has been examined in the present work. The reactions with boranes BX3·SMe2 (X = H, Cl, Br), BF3·OEt2 and BCl3 yield Lewis adducts [BICAAC·BH3] (1), [BICAAC·BHCl2] (2), [BICAAC·BH2Cl] (3), [BICAAC·BF3] (4), [BICAAC·BCl3] (5) and [BICAAC·BBr3] (6) respectively, whereas more hydridic boranes, 9-borabicyclo[3.3.1]nonane (9-BBN) and catecholborane (HBcat), enable the insertion of the carbene carbon into the B-H bond to form [BICAAC(H)-(9-BBN)] (7) and [BICAAC(H)-Bcat] (8). These complexes are the first examples of BICAAC-boron compounds and have been characterized using IR, multinuclear NMR spectroscopy, HRMS spectrometry and single crystal X-ray diffraction. Computational analyses were also performed to gain insight into the mechanism of B-H bond activation and adduct formation. Furthermore, the reactions of the BICAAC with boranes have been compared with the known reactions of CAACs and NHCs.
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Affiliation(s)
- Krishna K Manar
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Mohali 140306, Punjab, India.
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22
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Liu D, Thomas T, Gong H, Li F, Li Q, Song L, Azhagan T, Jiang H, Yang M. A mechanism of alkali metal carbonates catalysing the synthesis of β-hydroxyethyl sulfide with mercaptan and ethylene carbonate. Org Biomol Chem 2019; 17:9367-9374. [PMID: 31621741 DOI: 10.1039/c9ob01816f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of β-hydroxyethylation is essential to the current practice of organic chemistry. Here, we proposed a new and green route to synthesize 2-hydroxyethyl n-alkyl sulfide with n-alkyl mercaptan and ethylene carbonate (EC) in the presence of alkali carbonates as catalysts and revealed the mechanism by experiments and theoretical calculations. The reaction reported proceeds rapidly with high yields when it is performed at 120 °C and the catalytic loading is ∼1 mol%. This protocol is applicable to other mercaptans to synthesize the corresponding β-hydroxyethyl sulfide. Density functional theory-based calculations show the energy profile for the reaction pathway. The rate-determining step is the ring-opening of EC. A negatively charged O atom of alkali carbonates approaches the S atom of -SH under the influence of hydrogen bonds. An activated S atom that carries more negative charge serves as a nucleophilic reagent and assists in the ring-opening of EC by reducing the Mayer bond orders of the C1-O1 bond in EC. Alkali cations also contribute to the C1-O1 bond cleavage. The energy barrier for the ring-opening of EC decreases with the decrease of electronegativity of alkali cations. Subsequent transference of a H atom leads to the formation of β-hydroxyethyl sulfide, the dissociation of CO2 and the reduction of K2CO3.
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Affiliation(s)
- Dongliang Liu
- College of Chemistry, Chemical Engineering and Environment Engineering, Liaoning Shihua University, Fushun 113001, China.
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23
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Himmel H. Electron‐Deficient Triborane and Tetraborane Ring Compounds: Synthesis, Structure, and Bonding. Angew Chem Int Ed Engl 2019; 58:11600-11617. [DOI: 10.1002/anie.201900563] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Hans‐Jörg Himmel
- Anorganisch-Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
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24
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Himmel H. Elektronen‐defizitäre Triboran‐ und Tetraboran‐Ringverbindungen: Synthese, Struktur und Bindung. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201900563] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Hans‐Jörg Himmel
- Anorganisch-Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Deutschland
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25
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Arrowsmith M, Schweizer JI, Heinz M, Härterich M, Krummenacher I, Holthausen MC, Braunschweig H. Synthesis and reduction chemistry of mixed-Lewis-base-stabilised chloroborylenes. Chem Sci 2019; 10:5095-5103. [PMID: 31183061 PMCID: PMC6531816 DOI: 10.1039/c9sc01039d] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/06/2019] [Indexed: 01/22/2023] Open
Abstract
Mixed-base-stabilised chloroborylenes are easily accessed by twofold reduction of a cyclic (alkyl)(amino)carbene-supported trichloroborane in the presence of a second Lewis base, thus enabling fine-tuning of the electronic properties of the electron-rich borylene centre.
The one-electron reduction of (CAACMe)BCl3 (CAACMe = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) yields the dichloroboryl radical [(CAACMe)BCl2]˙. Furthermore, the twofold reduction of (CAACMe)BCl3 in the presence of a range of Lewis bases (L = CAACMe, N-heterocyclic carbene, phosphine) yields a series of doubly base-supported (CAACMe)LBCl chloroborylenes, all of which were structurally characterised. NMR and UV-vis spectroscopic and electrochemical data for (CAACMe)LBCl show that the boron centre becomes more electron-rich and the HOMO–LUMO gap widens as L becomes less π-accepting. A [(CAACMe)BCl2]– boryl anion coordination polymer was isolated as a potential intermediate in these reductions. In most cases the reduction of the chloroborylenes resulted in the formation of the corresponding hydroborylenes or derivatives thereof, as well as ligand C–H activation products.
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Affiliation(s)
- Merle Arrowsmith
- Institut für Anorganische Chemie , The Institute for Sustainable Chemistry & Catalysis with Boron , Julius-Maximilians-Universität Würzburg , Am Hubland , 97074 Würzburg , Germany .
| | - Julia I Schweizer
- Institut für Anorganische und Analytische Chemie , Goethe-Universität Frankfurt am Main , Max-von-Laue-Str. 7 , 60438 Frankfurt am Main , Germany
| | - Myron Heinz
- Institut für Anorganische und Analytische Chemie , Goethe-Universität Frankfurt am Main , Max-von-Laue-Str. 7 , 60438 Frankfurt am Main , Germany
| | - Marcel Härterich
- Institut für Anorganische Chemie , The Institute for Sustainable Chemistry & Catalysis with Boron , Julius-Maximilians-Universität Würzburg , Am Hubland , 97074 Würzburg , Germany .
| | - Ivo Krummenacher
- Institut für Anorganische Chemie , The Institute for Sustainable Chemistry & Catalysis with Boron , Julius-Maximilians-Universität Würzburg , Am Hubland , 97074 Würzburg , Germany .
| | - Max C Holthausen
- Institut für Anorganische und Analytische Chemie , Goethe-Universität Frankfurt am Main , Max-von-Laue-Str. 7 , 60438 Frankfurt am Main , Germany
| | - Holger Braunschweig
- Institut für Anorganische Chemie , The Institute for Sustainable Chemistry & Catalysis with Boron , Julius-Maximilians-Universität Würzburg , Am Hubland , 97074 Würzburg , Germany .
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26
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Yagi A, Kisu H, Yamashita M. Synthesis of a hydrogen-bridged tetraborane(6): a substituent effect of a diaminoboryl group toward the B–B multiple bond character. Dalton Trans 2019; 48:5496-5499. [DOI: 10.1039/c9dt01117j] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A hydrogen-bridging tetraborane(6) was synthesized from boryllithium, a boron nucleophile, in three steps.
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Affiliation(s)
- Atsumi Yagi
- Department of Molecular and Macromolecular Chemistry
- Graduate School of Engineering
- Nagoya University
- Nagoya
- Japan
| | - Haruki Kisu
- Department of Molecular and Macromolecular Chemistry
- Graduate School of Engineering
- Nagoya University
- Nagoya
- Japan
| | - Makoto Yamashita
- Department of Molecular and Macromolecular Chemistry
- Graduate School of Engineering
- Nagoya University
- Nagoya
- Japan
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27
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Yang MC, Su MD. Theoretical investigations of the reactivity of neutral molecules that feature an MM (M = B, Al, Ga, In, and Tl) double bond. NEW J CHEM 2019. [DOI: 10.1039/c9nj01294j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The geometry, the electronic structure and the reactivity of compounds that feature a central MM (M = group 13 element) double bond with two sterically bulky ligands (L1 = tBu2MeSi and L2 = NHCiPr), L1L2MML1L2 (Rea-MM) are studied at the B3LYP-D3(BJ)/def2-SVP level of theory.
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Affiliation(s)
- Ming-Chung Yang
- Department of Applied Chemistry, National Chiayi University
- Chiayi 60004
- Taiwan
| | - Ming-Der Su
- Department of Applied Chemistry, National Chiayi University
- Chiayi 60004
- Taiwan
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University
- Kaohsiung 80708
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28
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Arrowsmith M, Mattock JD, Hagspiel S, Krummenacher I, Vargas A, Braunschweig H. Facile Synthesis of a Stable Dihydroboryl {BH 2 } - Anion. Angew Chem Int Ed Engl 2018; 57:15272-15275. [PMID: 30238575 DOI: 10.1002/anie.201809983] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Indexed: 01/23/2023]
Abstract
While the one-electron reduction of (CAACMe )BH2 Br (CAACMe =1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) yields a hydride-shift isomer of the corresponding tetrahydrodiborane, a further reversible reduction leads to the first stable parent boryl anion, [(CAACMe )BH2 ]- , which acts as a powerful boron nucleophile.
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Affiliation(s)
- Merle Arrowsmith
- Institut für Anorganische Chemie, 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
| | - James D Mattock
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton, BN1 9QJ, Sussex, UK
| | - Stephan Hagspiel
- Institut für Anorganische Chemie, 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
- Institut für Anorganische Chemie, 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
| | - Alfredo Vargas
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton, BN1 9QJ, Sussex, UK
| | - Holger Braunschweig
- Institut für Anorganische Chemie, 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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29
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Arrowsmith M, Mattock JD, Hagspiel S, Krummenacher I, Vargas A, Braunschweig H. Einfacher Zugang zum ersten stabilen {BH
2
}
−
Dihydroborylanion. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201809983] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Merle Arrowsmith
- Institut für Anorganische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - James D. Mattock
- Department of ChemistrySchool of Life SciencesUniversity of Sussex Brighton BN1 9QJ Sussex Großbritannien
| | - Stephan Hagspiel
- Institut für Anorganische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Ivo Krummenacher
- Institut für Anorganische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Alfredo Vargas
- Department of ChemistrySchool of Life SciencesUniversity of Sussex Brighton BN1 9QJ Sussex Großbritannien
| | - Holger Braunschweig
- Institut für Anorganische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
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30
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Welz E, Böhnke J, Dewhurst RD, Braunschweig H, Engels B. Unravelling the Dramatic Electrostructural Differences Between N-Heterocyclic Carbene- and Cyclic (Alkyl)(amino)carbene-Stabilized Low-Valent Main Group Species. J Am Chem Soc 2018; 140:12580-12591. [DOI: 10.1021/jacs.8b07644] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Eileen Welz
- Institute for Physical and Theoretical Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Julian Böhnke
- 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
| | - 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 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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31
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Böhnke J, Arrowsmith M, Braunschweig H. Reactivity Enhancement of a Zerovalent Diboron Compound by Desymmetrization. J Am Chem Soc 2018; 140:10368-10373. [PMID: 30040887 DOI: 10.1021/jacs.8b06930] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The desymmetrization of the cyclic (alkyl)(amino)carbene-supported diboracumulene B2(cAACMe)2 (cAACMe = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) by monoadduct formation with IMeMe (1,3-dimethylimidazol-2-ylidene) yields the zerovalent sp-sp2 diboron compound B2(cAACMe)2(IMeMe), which provides a versatile platform for the synthesis of novel symmetrical and unsymmetrical zerovalent sp2-sp2 diboron compounds by adduct formation with IMeMe and CO, respectively. Furthermore, B2(cAACMe)2(IMeMe) displays enhanced reactivity compared to its symmetrical precursor, undergoing spontaneous intramolecular C-H activation and facile twofold hydrogenation, the latter resulting in B-B bond cleavage and the formation of the mixed-base parent borylene (cAACMe)(IMeMe)BH.
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Affiliation(s)
- Julian Böhnke
- Institut für Anorganische Chemie , 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
| | - Merle Arrowsmith
- Institut für Anorganische Chemie , 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
- Institut für Anorganische Chemie , 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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