1
|
Li S, Shiri F, Xu G, Yiu SM, Lee HK, Ng TH, Lin Z, Lu Z. Reactivity of a Hexaaryldiboron(6) Dianion as Boryl Radical Anions. J Am Chem Soc 2024. [PMID: 38864188 DOI: 10.1021/jacs.4c04253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Our study unveils a novel approach to accessing boryl radicals through the spontaneous homolytic cleavage of B-B bonds. We synthesized a hexaaryl-substituted diboron(6) dianion, 1, via the reductive B-B coupling of 9-borafluorene. Intriguingly, compound 1 exhibits the ability to undergo homolytic B-B bond cleavage, leading to the formation of boryl radical anions, as confirmed by EPR studies, in the presence of the 2.2.2-cryptand at room temperature. Moreover, it directly reacts with diphenylacetylene, producing an unprecedented 1,6-diborylated allene species, where the phenyl ring is dearomatized. Density functional theory computational studies suggest that homolytic B-B bond cleavage is favored in the reaction path, and the formation of the boryl radical anion is crucial for dearomatization. Additionally, it achieves the dearomative diborylation of anthracene and the activation of elemental sulfur/selenium under mild conditions. The borylation products have been successfully characterized by NMR spectra, HRMS, and X-ray single-crystal diffraction.
Collapse
Affiliation(s)
- Shuchang Li
- Department of Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong SAR 999077, P. R. China
| | - Farshad Shiri
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR 999077, P. R. China
| | - Gan Xu
- Department of Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong SAR 999077, P. R. China
| | - Shek-Man Yiu
- Department of Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong SAR 999077, P. R. China
| | - Hung Kay Lee
- Department of Chemistry, Chinese University of Hong Kong, Shatin, Hong Kong SAR 999077, P. R. China
| | - Tik Hong Ng
- Department of Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong SAR 999077, P. R. China
| | - Zhenyang Lin
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR 999077, P. R. China
| | - Zhenpin Lu
- Department of Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong SAR 999077, P. R. China
| |
Collapse
|
2
|
Zapf L, Finze M. Lewis Acid Decorated Hexacyanodiborane(6) Dianion. Angew Chem Int Ed Engl 2024; 63:e202401681. [PMID: 38530744 DOI: 10.1002/anie.202401681] [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: 01/24/2024] [Revised: 03/03/2024] [Accepted: 03/04/2024] [Indexed: 03/28/2024]
Abstract
First examples of diborane(6) dianions decorated with weakly coordination B(C6F5)3 (BCF) groups and SiEt3 + moieties have been synthesized demonstrating the synthetic potential of the [B2(CN)6]2- dianion. [B2{CNB(C6F5)3}6]2- (1) was isolated as potassium and tetrabutylammonium salt. 1 is a rare example for a weakly coordinating dianion and it was used for the stabilization of the carbocation [Ph3C]+ and the oxonium acid [H(OEt2)2]+. Reaction of [Ph3C]21 with HSiEt3 resulted in the silylated neutral diborane(6) [B2{CNB(C6F5)3}4(CNSiEt3)2] (2) in which two BCF groups have been selectively replaced by SiEt3 + substituents, underscoring the stability and chemical versatility of the [B2(CN)6]2- dianion. The chemical properties and physicochemical data of 1 and 2 provide insight into electronic, coordinating, and steric properties of theses novel diborane(6) compounds.
Collapse
Affiliation(s)
- Ludwig Zapf
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Maik Finze
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| |
Collapse
|
3
|
Koshino K, Kinjo R. A Highly Strained Al-Al σ-Bond in Dianionic Aluminum Analog of Oxirane for Molecule Activation. J Am Chem Soc 2021; 143:18172-18180. [PMID: 34697939 DOI: 10.1021/jacs.1c07389] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Since aluminum is the most electropositive element among the p-block elements, the construction of molecules bearing a dianionic Al-Al σ-bond is inherently highly challenging. Herein, we report the first synthesis of a dianionic dialane(6) 2 based on the Al2O three-membered ring scaffold, namely, an aluminum analog of oxirane. The structure of 2 has been unambiguously ascertained by spectroscopic analysis as well as X-ray crystallography, and computational studies revealed that 2 bears a highly strained Al-Al σ-bond. 2 readily reacts with the unsaturated substrates such as isocyanide, ethylene, and ketone, concomitant with the cleavage of the Al-Al σ-bond under mild conditions, leading to the four- and five-membered heterocycles 3-5. Furthermore, the reaction of 2 with two molecules of benzonitrile (PhCN) furnishes a seven-membered heterocycle 6, resulting from the C-C coupling reaction of PhCN. We further delineate that 2 selectively activates an arene ring C-C bond of biphenylene, rendering a di-Al-substituted benzo[8]annulene derivative 7. Preliminary computational studies propose that the stepwise reaction mechanism involves the Al-Al σ-bond cleavage, dearomative Al-C bond formation, subsequent sigmatropic [1,3]shifts, and a pericyclic reaction.
Collapse
Affiliation(s)
- Kota Koshino
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
| | - Rei Kinjo
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
| |
Collapse
|
4
|
Thiess T, Bélanger‐Chabot G, Fantuzzi F, Michel M, Ernst M, Engels B, Braunschweig H. Diborane(4) Azides: Surprisingly Stable Sources of Transient Iminoboranes. Angew Chem Int Ed Engl 2020; 59:15480-15486. [PMID: 32270577 PMCID: PMC7497274 DOI: 10.1002/anie.202003050] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/06/2020] [Indexed: 01/30/2023]
Abstract
Herein we describe the first examples of isolable electron-precise diboranes(4) that bear azide moieties: the acyclic 1,2-diazido-1,2-bis(dimethylamino)diborane(4) and the cyclic 1,4-diaryl-2,3-diazido-1,4-diaza-2,3-diborinines (aryl=mesityl, 2,6-xylyl, 4-tolyl). The reported examples are not only stable enough to be observed and isolated (putative transient diborane(4) azides previously reported by our group spontaneously decompose even below room temperature), but some of them are even robust enough to undergo controlled pyrolysis without explosive decomposition at temperatures well above 100 °C. In two cases, the controlled pyrolysis allows the isolation of complex diazaboretidines, which are the apparent dimerization products of endocyclic boryl-iminoboranes.
Collapse
Affiliation(s)
- Torsten Thiess
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Guillaume Bélanger‐Chabot
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Département de ChimieUniversité Laval1045 Avenue de la MédecineQuébecG1V 0A6Canada
| | - Felipe Fantuzzi
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität WürzburgEmil-Fischer-Straße 4297074WürzburgGermany
| | - Maximilian Michel
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Moritz Ernst
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Bernd Engels
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität WürzburgEmil-Fischer-Straße 4297074WürzburgGermany
| | - Holger Braunschweig
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| |
Collapse
|
5
|
Thiess T, Bélanger‐Chabot G, Fantuzzi F, Michel M, Ernst M, Engels B, Braunschweig H. Diboran(4)azide als stabile Quelle für kurzlebige Iminoborane. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202003050] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Torsten Thiess
- Institut für Anorganische Chemie und Institut für nachhaltige Chemie und Katalyse mit Bor als Schlüsselelement Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Guillaume Bélanger‐Chabot
- Institut für Anorganische Chemie und Institut für nachhaltige Chemie und Katalyse mit Bor als Schlüsselelement Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Département de Chimie Université Laval 1045 Avenue de la Médecine Québec G1V 0A6 Kanada
| | - Felipe Fantuzzi
- Institut für Anorganische Chemie und Institut für nachhaltige Chemie und Katalyse mit Bor als Schlüsselelement Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für Physikalische und Theoretische Chemie Julius-Maximilians-Universität Würzburg Emil-Fischer-Straße 42 97074 Würzburg Deutschland
| | - Maximilian Michel
- Institut für Anorganische Chemie und Institut für nachhaltige Chemie und Katalyse mit Bor als Schlüsselelement Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Moritz Ernst
- Institut für Anorganische Chemie und Institut für nachhaltige Chemie und Katalyse mit Bor als Schlüsselelement Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Bernd Engels
- Institut für Physikalische und Theoretische Chemie Julius-Maximilians-Universität Würzburg Emil-Fischer-Straße 42 97074 Würzburg Deutschland
| | - Holger Braunschweig
- Institut für Anorganische Chemie und Institut für nachhaltige Chemie und Katalyse mit Bor als Schlüsselelement Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| |
Collapse
|
6
|
Vogler D, Wolf N, Kaifer E, Himmel HJ. Electron transfer in complexes of B II cations with organic π-acceptors: a combined experimental and quantum-chemical study. Dalton Trans 2019; 48:14354-14366. [PMID: 31513209 DOI: 10.1039/c9dt03151k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Due to their combined Lewis acidity and electron-donor capability, BII cations exhibit an interesting reactivity, which is almost unexplored so far. In this work, we compare the reduction in a dicationic diborane of a series of vicinal diones with different redox potentials, namely 3,5-di-tert-butylbenzoquinone, 3,4,5,6-tetrachlorobenzoquinone, 1,2-naphthalene-dione, 9,10-phenanthrene-dione, 2,2'-dichlorobenzil, benzil and 1,2-acenaphthylene-dione. The experimental work is complemented by quantum-chemical calculations, illuminating the electron-transfer step in the reactions.
Collapse
Affiliation(s)
- Daniel Vogler
- Anorganisch-Chemisches Institut, Ruprecht-Karls-University of Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
| | - Nina Wolf
- Anorganisch-Chemisches Institut, Ruprecht-Karls-University of Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
| | - Elisabeth Kaifer
- Anorganisch-Chemisches Institut, Ruprecht-Karls-University of Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
| | - Hans-Jörg Himmel
- Anorganisch-Chemisches Institut, Ruprecht-Karls-University of Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
| |
Collapse
|
7
|
Bélanger‐Chabot G, Braunschweig H. Hexahalogendiborat‐Dianionen: Eine neue Klasse binärer Borhalogenide. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201906666] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Guillaume Bélanger‐Chabot
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Holger Braunschweig
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institute for Sustainable Chemistry & Catalysis with Boron Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| |
Collapse
|
8
|
Bélanger-Chabot G, Braunschweig H. Hexahalodiborate Dianions: A New Family of Binary Boron Halides. Angew Chem Int Ed Engl 2019; 58:14270-14274. [PMID: 31361383 PMCID: PMC7028027 DOI: 10.1002/anie.201906666] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Indexed: 01/05/2023]
Abstract
The electron‐precise binary boron subhalide species [B2X6]2− X=F, Br, I) were synthesized and their structures confirmed by X‐ray crystallography. The existence of the previously claimed [B2Cl6]2−, which had been questioned, was also confirmed by X‐ray crystallography. The dianions are isoelectronic to hexahaloethanes, are subhalide analogues of the well‐known tetrahaloborate anions (BX4−), and are rare examples of molecular electron‐precise binary boron species beyond B2X4, BX3, and [BX4]−.
Collapse
Affiliation(s)
- Guillaume Bélanger-Chabot
- 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
| |
Collapse
|
9
|
Cao LL, Stephan DW. Homolytic Cleavage Reactions of a Neutral Doubly Base Stabilized Diborane(4). Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00522] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Levy L. Cao
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, Canada M5S 3H6
| | - Douglas W. Stephan
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, Canada M5S 3H6
| |
Collapse
|
10
|
Kong L, Lu W, Li Y, Ganguly R, Kinjo R. Isolation of a Diborane(6) Dication: Formation and Cleavage of an Electron-Precise B(sp3)–B(sp3) Bond. J Am Chem Soc 2016; 138:8623-9. [DOI: 10.1021/jacs.6b04858] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lingbing Kong
- Division
of Chemistry and Biological Chemistry, School of Physical
and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University, 637371, Singapore
| | - Wei Lu
- Division
of Chemistry and Biological Chemistry, School of Physical
and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University, 637371, Singapore
| | - Yongxin Li
- Division
of Chemistry and Biological Chemistry, School of Physical
and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University, 637371, Singapore
| | - Rakesh Ganguly
- Division
of Chemistry and Biological Chemistry, School of Physical
and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University, 637371, Singapore
| | - Rei Kinjo
- Division
of Chemistry and Biological Chemistry, School of Physical
and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University, 637371, Singapore
| |
Collapse
|
11
|
Landmann J, Sprenger JAP, Hailmann M, Bernhardt-Pitchougina V, Willner H, Ignat'ev N, Bernhardt E, Finze M. The Hexacyanodiborane(6) Dianion [B2(CN)6]2−. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/anie.201504579] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
12
|
Landmann J, Sprenger JAP, Hailmann M, Bernhardt-Pitchougina V, Willner H, Ignat'ev N, Bernhardt E, Finze M. Das Hexacyanodiboran(6)-Dianion [B2(CN)6]2−. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201504579] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
13
|
Shoji Y, Matsuo T, Hashizume D, Gutmann MJ, Fueno H, Tanaka K, Tamao K. Boron-boron σ-bond formation by two-electron reduction of a H-bridged dimer of monoborane. J Am Chem Soc 2011; 133:11058-61. [PMID: 21711029 DOI: 10.1021/ja203333j] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Diborane(6) as a H-bridged dimer of monoborane can be converted cleanly by two-electron reduction into diborane(6) dianion, which is isoelectronic with ethane, through B-B σ-bond formation when each boron atom has a bulky ligand on it. The existence of the B-B σ bond is supported by the X-ray molecular structure [B-B bond length of 1.924(3) Å], NMR studies, magnetic susceptibility measurements, and DFT calculations. Stepwise hydride abstraction reactions of the diborane(6) dianion produce the corresponding H-bridged diborane(5) anion and doubly H-bridged diborane(4) without B-B bond scission.
Collapse
Affiliation(s)
- Yoshiaki Shoji
- Functional Elemento-Organic Chemistry Unit, RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | | | | | | | | | | | | |
Collapse
|
14
|
Eckert AK, Rodríguez-Morgade MS, Torres T. Molecular diabolos: synthesis of subphthalocyanine-based diboranes. Chem Commun (Camb) 2007:4104-6. [DOI: 10.1039/b708496j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
15
|
|
16
|
Nachtigal C, Steuer B, Preetz W. Selenocyanato Derivatives of Hydro-closo-borates: Syntheses and Crystal Structures of (PPh4)2[SeCN)BnHn–1] (n = 6, 10, 12). ACTA ACUST UNITED AC 1996. [DOI: 10.1002/cber.19961291220] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|