1
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Hollister KK, Wentz KE, Gilliard RJ. Redox- and Charge-State Dependent Trends in 5, 6, and 7-Membered Boron Heterocycles: A Neutral Ligand Coordination Chemistry Approach to Boracyclic Cations, Anions, and Radicals. Acc Chem Res 2024; 57:1510-1522. [PMID: 38708938 DOI: 10.1021/acs.accounts.4c00096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
ConspectusBoron heterocycles represent an important subset of heteroatom-incorporated rings, attracting attention from organic, inorganic, and materials chemists. The empty pz orbital at the boron center makes them stand out as quintessential Lewis acidic molecules, also serving as a means to modulate electronic structure and photophysical properties in a facile manner. As boracycles are ripe for extensive functionalization, they are used in catalysis, chemical biology, materials science, and continue to be explored as chemical synthons for conjugated materials and reagents. Neutral boron(III)-incorporated polycyclic molecules are some of the most studied types of boracycles, and understanding their redox transformations is important for applications relying on electron transfer and charge transport. While relevant redox species can often be electrochemically observed, it remains challenging to isolate and characterize boracycles where the boron center and/or polycyclic skeleton have been chemically reduced.We describe our recent work isolating 5-, 6-, and 7-membered boracyclic radicals, anions, and cations, focusing on stabilization strategies, ligand-mediated bonding situations, and reactivity. We present a versatile neutral ligand coordination chemistry approach that permits the transformation of boracycles from potent electrophiles to powerful nucleophilic heterocycles that facilitate diverse electron transfer and bond activation chemistry. Although there are a wide range of suitable stabilizing ligands, we have employed both diamino-N-heterocyclic carbenes (NHCs) and cyclic(alkyl)(amino) carbenes (CAACs), which led to boracycles with tunable electronic structures and aromaticity trends. We highlight successful isolation of borafluorene radicals and demonstrate their reversible redox behavior, undergoing oxidation to the cation or reduction to the anion. The borafluorene anion is a chemical synthon that has been used to prepare boryl main-group and transition-metal bonds, luminescent oxabora-spirocycles, borafluorenate-crown ethers, and CO-releasing molecules via carbon dioxide activation. We expanded to 6-membered boracycles and characterized neutral bis(NHC-supported 9-boraphenanthrene)s and the corresponding bis(CAAC-stabilized 9-boraphenanthrene) biradical. We detail the interconvertible multiredox states of boraphenalene, where the boraphenalenyl radical, anion, and cation mimic the charge-states of the all-hydrocarbon analogue. Reactivity studies of the boraphenalenyl anion displayed unusual nucleophilic reactivity at multiple sites on the periphery of the boraphenalenyl tricyclic scaffold. Reduced borepins, 7-membered boron containing heterocycles, have also been isolated. We used a stepwise one-pot synthesis combining the halo-borepin precursor, CAAC, and KC8 to afford the monomeric borepin radicals and anions. The π-system was extended to contain two borepin rings fused in a pentacyclic scaffold, which permitted isolation of diborepin biradicals and a diborepin containing a dibora-quinone core.Our goal is to provide a guide explaining the current structure-function trends and isolation strategies for redox-active boron-incorporated polycyclic molecules to initiate the rational design and use of these types of compounds across a vast chemical space.
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Affiliation(s)
- Kimberly K Hollister
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Building 18-596, Cambridge, Massachusetts 02139-4307, United States
| | - Kelsie E Wentz
- Department of Chemistry, Johns Hopkins University, Remson Hall, 3400 N Charles Street, Baltimore, Maryland 21218-2625, United States
| | - Robert J Gilliard
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Building 18-596, Cambridge, Massachusetts 02139-4307, United States
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2
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Zeng J, You F, Zhu J. Screening seven-electron boron-centered radicals for dinitrogen activation. J Comput Chem 2024; 45:648-654. [PMID: 38073508 DOI: 10.1002/jcc.27281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 11/23/2023] [Accepted: 11/27/2023] [Indexed: 03/02/2024]
Abstract
The activation of dinitrogen is significant as nitrogen-containing compounds play an important role in industries. However, the inert NN triple bond caused by its large HOMO-LUMO gap (10.8 eV) and high bond dissociation energy (945 kJ mol-1 ) renders its activation under mild conditions particularly challenging. Recent progress shows that a few main group species can mimic transition metal complexes to activate dinitrogen. Here, we demonstrate that a series of seven-electron (7e) boron-centered radical can be used to activate N2 via density functional theory calculations. It is found that boron-centered radicals containing amine ligand perform best on the thermodynamics of dinitrogen activation. In addition, when electron-donating groups are introduced at the boron atom, these radicals can be used to activate N2 with low reaction barriers. Further analysis suggests that the electron transfer from the boron atom to the π* orbitals of dinitrogen is essential for its activation. Our findings suggest great potential of 7e boron radicals in the field of dinitrogen activation.
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Affiliation(s)
- Jie Zeng
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, China
- Pharmaceutical Research Institute, Wuhan Institute of Technology, Wuhan, China
| | - Feiying You
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Jun Zhu
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, China
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
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3
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Deng CL, Hollister KK, Molino A, Tra BYE, Dickie DA, Wilson DJD, Gilliard RJ. Unveiling Three Interconvertible Redox States of Boraphenalene. J Am Chem Soc 2024; 146:6145-6156. [PMID: 38380615 DOI: 10.1021/jacs.3c13726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Neutral 1-boraphenalene displays the isoelectronic structure of the phenalenyl carbocation and is expected to behave as an attractive organoboron multi-redox system. However, the isolation of new redox states have remained elusive even though the preparation of neutral boron(III)-containing phenalene compounds have been extensively studied. Herein, we have adopted an N-heterocyclic carbene ligand stabilization approach to achieve the first isolation of the stable and ambipolar 1-boraphenalenyl radical 1•. The 1-boraphenalenyl cation 1+ and anion 1- have also been electrochemically observed and chemically isolated, representing new redox forms of boraphenalene for the study of non-Kekulé polynuclear benzenoid molecules. Experimental and theoretical investigations suggest that the interconvertible three-redox-state species undergo reversible electronic structure modifications, which primarily take place on the polycyclic framework of the molecules, exhibiting atypical behavior compared to known donor-stabilized organoboron compounds. Initial reactivity studies, aromaticity evaluations, and photophysical studies show redox-state-dependent trends. While 1+ is luminescent in both the solution and solid states, 1• exhibits boron-centered reactivity and 1- undergoes substitution chemistry on the boraphenalenyl skeleton and serves as a single-electron transfer reductant.
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Affiliation(s)
- Chun-Lin Deng
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Kimberly K Hollister
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Andrew Molino
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086 Victoria, Australia
| | - Bi Youan E Tra
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Diane A Dickie
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - David J D Wilson
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086 Victoria, Australia
| | - Robert J Gilliard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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4
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Ritch JS. Chalcogen-substituted carbenes: a density functional study of structure, stability, and donor ability. RSC Adv 2023; 13:16828-16836. [PMID: 37283867 PMCID: PMC10240176 DOI: 10.1039/d3ra03324d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 05/26/2023] [Indexed: 06/08/2023] Open
Abstract
Chalcogen-substituted carbenes are examined computationally using density functional theory. Several approaches are used to assess the stability and reactivity of chalcogenazol-2-ylidene carbenes (NEHCs; E = O, S, Se, Te). The known unsaturated species 1,3-dimethylimidazol-2-ylidene is studied at the same level of theory as the NEHC molecules, as a reference. Electronic structures, stability towards dimerization, and ligand properties are discussed. The results highlight the NEHCs as potentially valuable ancillary ligands for stabilizing low-valent metals or paramagnetic main group molecules. A simple, effective computational method for evaluating σ donor ability and π acidity of carbenes is presented.
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Affiliation(s)
- Jamie S Ritch
- Department of Chemistry, The University of Winnipeg 515 Portage Avenue Winnipeg MB R3B 2E9 Canada +1-204-774-2401 +1-204-786-9730
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5
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Liu TT, Chen J, Chen XL, Ma L, Guan BT, Lin Z, Shi ZJ. Neutral Boryl Radicals in Mixed-Valent B (III) Br-B (II) Adducts. Chemistry 2023; 29:e202202634. [PMID: 36217568 DOI: 10.1002/chem.202202634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Indexed: 11/06/2022]
Abstract
The general strategies to stabilize a boryl radical involve single electron delocalization by π-system and the steric hinderance from bulky groups. Herein, a new class of boryl radicals is reported, with intramolecular mixed-valent B(III) Br-B(II) adducts ligated by a cyclic (alkyl)(amino)carbene (CAAC). The radicals feature a large spin density on the boron center, which is ascertained by EPR spectroscopy and DFT calculations. Structural and computational analyses revealed that the stability of radical species was assisted by the CAAC ligand and a weak but significant B(III)Br-B(II) interaction, suggesting a cooperative avenue for stabilization of boryl radicals. Two-electron reduction of these new boryl radicals provides C-H insertion products via a borylene intermediate.
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Affiliation(s)
- Tong-Tong Liu
- Department of Chemistry, Fudan University, Shanghai, 200438, P. R. China
| | - Jiaxin Chen
- Department of Chemistry, The Hong Kong University of Science and Technology Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Xin-Lei Chen
- Department of Chemistry, Fudan University, Shanghai, 200438, P. R. China
| | - Li Ma
- Department of Chemistry, Fudan University, Shanghai, 200438, P. R. China
| | - Bing-Tao Guan
- Department of Chemistry, Fudan University, Shanghai, 200438, P. R. China
| | - Zhenyang Lin
- Department of Chemistry, The Hong Kong University of Science and Technology Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Zhang-Jie Shi
- Department of Chemistry, Fudan University, Shanghai, 200438, P. R. China
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6
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Wentz KE, Molino A, Freeman LA, Dickie DA, Wilson DJD, Gilliard RJ. Systematic Electronic and Structural Studies of 9-Carbene-9-Borafluorene Monoanions and Transformations into Luminescent Boron Spirocycles. Inorg Chem 2022; 61:17049-17058. [PMID: 36259945 DOI: 10.1021/acs.inorgchem.2c01945] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The impact of the exact spatial arrangement of the alkali metal on the electronic properties of 9-carbene-9-borafluorene monoanions is assessed, and a series of [K][9-CAAC-9-borafluorene] complexes (1-4) have been isolated (CAAC = cyclic(alkyl)(amino) carbene, (2,6-diisopropylphenyl)-4,4-diethyl-2,2-dimethyl-pyrrolidin-5-ylidene). Compound 1, which contains [B]-K(THF)3 interactions, is compared to charge-separated 2-4, which were prepared by capturing the potassium cations with 18-crown-6, 2.2.2-cryptand, or 1,10-phenanthroline. Notably, the 11B NMR spectra of charge-separated borafluorene monoanions 2-4 show distinct low-field signatures compared to 1. Theoretical calculations indicate that charge separation may be exploited to influence the nucleophilic and electron transfer properties of 9-carbene-9-borafluorene monoanions. When [K(2.2.2-cryptand)][9-CAAC-9-borafluorene] (3) is reacted with 9,10-phenanthrenequinone and 1,10-phenanthroline-5,6-dione, the carbene ligand is displaced, and new air-stable R2BO2 spirocycles are formed (5 and 6, respectively). Remarkably, compounds 5 and 6 display fluorescence under UV light in both the solid and solution phases with quantum yields of up to 20%. In addition, a drastic red-shift in the emission color is observed in 6 because of the presence of the nitrogen atoms on the phenanthroline moiety. Mechanistic insights into the formation of these spirocycles are also described based on density functional theory calculations.
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Affiliation(s)
- Kelsie E Wentz
- Department of Chemistry, University of Virginia, Charlottesville 22904, Virginia, United States
| | - Andrew Molino
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia
| | - Lucas A Freeman
- Department of Chemistry, University of Virginia, Charlottesville 22904, Virginia, United States
| | - Diane A Dickie
- Department of Chemistry, University of Virginia, Charlottesville 22904, Virginia, United States
| | - David J D Wilson
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia
| | - Robert J Gilliard
- Department of Chemistry, University of Virginia, Charlottesville 22904, Virginia, United States
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7
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Wentz KE, Molino A, Freeman LA, Dickie DA, Wilson DJD, Gilliard RJ. Activation of Carbon Dioxide by 9-Carbene-9-borafluorene Monoanion: Carbon Monoxide Releasing Transformation of Trioxaborinanone to Luminescent Dioxaborinanone. J Am Chem Soc 2022; 144:16276-16281. [PMID: 36037435 DOI: 10.1021/jacs.2c06845] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The first structurally characterized example of a trioxaborinanone (2) is produced by the reaction of a 9-carbene-9-borafluorene monoanion and carbon dioxide. When compound 2 is heated or irradiated with UV light, carbon monoxide (CO) is released, and a luminescent dioxaborinanone (3) is formed. Notably, carbon monoxide releasing molecules (CORMs) are of interest for their ability to deliver a specific amount of CO. Due to the turn-on fluorescence observed as a result of the conversion to 3, CORM 2 serves as a means to optically observe CO loss "by eye" under thermal or photochemical conditions.
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Affiliation(s)
- Kelsie E Wentz
- Department of Chemistry, University of Virginia, 409 McCormick Road, Charlottesville, Virginia 22904, United States
| | - Andrew Molino
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia
| | - Lucas A Freeman
- Department of Chemistry, University of Virginia, 409 McCormick Road, Charlottesville, Virginia 22904, United States
| | - Diane A Dickie
- Department of Chemistry, University of Virginia, 409 McCormick Road, Charlottesville, Virginia 22904, United States
| | - David J D Wilson
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia
| | - Robert J Gilliard
- Department of Chemistry, University of Virginia, 409 McCormick Road, Charlottesville, Virginia 22904, United States
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8
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Häring M, Kerpen C, Ribbeck T, Hennig PT, Bertermann R, Ignat'ev NV, Finze M. Dismutation of Tricyanoboryllead Compounds: The Homoleptic Tetrakis(tricyanoboryl)plumbate Tetraanion. Angew Chem Int Ed Engl 2022; 61:e202202882. [PMID: 35266266 PMCID: PMC9322310 DOI: 10.1002/anie.202202882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Indexed: 11/29/2022]
Abstract
A series of unprecedently air‐stable (tricyanoboryl)plumbate anions was obtained by the reaction of the boron‐centered nucleophile B(CN)32− with triorganyllead halides. Salts of the anions [R3PbB(CN)3]− (R=Ph, Et) were isolated and found to be stable in air at room temperature. In the case of Me3PbHal (Hal=Cl, Br), a mixture of the anions [Me4−nPb{B(CN)3}n]n− (n=1, 2) was obtained. The [Et3PbB(CN)3]− ion undergoes stepwise dismutation in aqueous solution to yield the plumbate anions [Et4−nPb{B(CN)3}n]n− (n=1–4) and PbEt4 as by‐product. The reaction rate increases with decreasing pH value of the aqueous solution or by bubbling O2 through the reaction mixture. Adjustment of the conditions allowed the selective formation and isolation of salts of all anions of the series [Et4−nPb{B(CN)3}n]n− (n=2–4) including the homoleptic tetraanion [Pb{B(CN)3}4]4−.
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Affiliation(s)
- Mathias Häring
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Christoph Kerpen
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Tatjana Ribbeck
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Philipp T. Hennig
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Rüdiger Bertermann
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Nikolai V. Ignat'ev
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Consultant, Merck KGaA 64293 Darmstadt Germany
| | - Maik Finze
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
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9
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Hollister KK, Yang W, Mondol R, Wentz KE, Molino A, Kaur A, Dickie DA, Frenking G, Pan S, Wilson DJD, Gilliard RJ. Isolation of Stable Borepin Radicals and Anions. Angew Chem Int Ed Engl 2022; 61:e202202516. [PMID: 35289046 PMCID: PMC9324096 DOI: 10.1002/anie.202202516] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Indexed: 12/31/2022]
Abstract
Borepin, a 7‐membered boron‐containing heterocycle, has become an emerging molecular platform for the development of new materials and optoelectronics. While electron‐deficient borepins are well‐established, reduced electron‐rich species have remained elusive. Herein we report the first isolable, crystalline borepin radical (2 a, 2 b) and anion (3 a, 3 b) complexes, which have been synthesized by potassium graphite (KC8) reduction of cyclic(alkyl)(amino) carbene‐dibenzo[b,d]borepin precursors. Borepin radicals and anions have been characterized by EPR or NMR, elemental analysis, X‐ray crystallography, and cyclic voltammetry. In addition, the bonding features have been investigated computationally using density functional theory.
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Affiliation(s)
- Kimberly K Hollister
- Department of Chemistry, University of Virginia, 409 McCormick Rd./PO Box 400319, Charlottesville, VA 22904, USA
| | - Wenlong Yang
- Department of Chemistry, University of Virginia, 409 McCormick Rd./PO Box 400319, Charlottesville, VA 22904, USA
| | - Ranajit Mondol
- Department of Chemistry, University of Virginia, 409 McCormick Rd./PO Box 400319, Charlottesville, VA 22904, USA
| | - Kelsie E Wentz
- Department of Chemistry, University of Virginia, 409 McCormick Rd./PO Box 400319, Charlottesville, VA 22904, USA
| | - Andrew Molino
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, Latrobe University, Melbourne, 3086, Victoria, Australia
| | - Aishvaryadeep Kaur
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, Latrobe University, Melbourne, 3086, Victoria, Australia
| | - Diane A Dickie
- Department of Chemistry, University of Virginia, 409 McCormick Rd./PO Box 400319, Charlottesville, VA 22904, USA
| | - Gernot Frenking
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35043, Marburg, Germany
| | - Sudip Pan
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35043, Marburg, Germany
| | - David J D Wilson
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, Latrobe University, Melbourne, 3086, Victoria, Australia
| | - Robert J Gilliard
- Department of Chemistry, University of Virginia, 409 McCormick Rd./PO Box 400319, Charlottesville, VA 22904, USA
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10
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Häring M, Kerpen C, Ribbeck T, Hennig PT, Bertermann R, Ignat'ev NV, Finze M. Dismutation von Tricyanoborblei‐Verbindungen: Das homoleptische Tetrakis(tricyanoboryl)plumbat‐Tetraanion. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202882] [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)
- Mathias Häring
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Christoph Kerpen
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Tatjana Ribbeck
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Philipp T. Hennig
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Rüdiger Bertermann
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Nikolai V. Ignat'ev
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Consultant, Merck KGaA 64293 Darmstadt Deutschland
| | - Maik Finze
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
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11
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Hollister KK, Yang W, Mondol R, Wentz KE, Molino A, Kaur A, Dickie DA, Frenking G, Pan S, Wilson DJD, Gilliard RJ. Isolation of Stable Borepin Radicals and Anions. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Kimberly K. Hollister
- Department of Chemistry University of Virginia 409 McCormick Rd./PO Box 400319 Charlottesville VA 22904 USA
| | - Wenlong Yang
- Department of Chemistry University of Virginia 409 McCormick Rd./PO Box 400319 Charlottesville VA 22904 USA
| | - Ranajit Mondol
- Department of Chemistry University of Virginia 409 McCormick Rd./PO Box 400319 Charlottesville VA 22904 USA
| | - Kelsie E. Wentz
- Department of Chemistry University of Virginia 409 McCormick Rd./PO Box 400319 Charlottesville VA 22904 USA
| | - Andrew Molino
- Department of Chemistry and Physics La Trobe Institute for Molecular Science Latrobe University Melbourne 3086, Victoria Australia
| | - Aishvaryadeep Kaur
- Department of Chemistry and Physics La Trobe Institute for Molecular Science Latrobe University Melbourne 3086, Victoria Australia
| | - Diane A. Dickie
- Department of Chemistry University of Virginia 409 McCormick Rd./PO Box 400319 Charlottesville VA 22904 USA
| | - Gernot Frenking
- Fachbereich Chemie Philipps-Universität Marburg Hans-Meerwein-Strasse 4 35043 Marburg Germany
| | - Sudip Pan
- Fachbereich Chemie Philipps-Universität Marburg Hans-Meerwein-Strasse 4 35043 Marburg Germany
| | - David J. D. Wilson
- Department of Chemistry and Physics La Trobe Institute for Molecular Science Latrobe University Melbourne 3086, Victoria Australia
| | - Robert J. Gilliard
- Department of Chemistry University of Virginia 409 McCormick Rd./PO Box 400319 Charlottesville VA 22904 USA
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12
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Zeng J, Dong S, Dai C, Zhu J. Predicting Dinitrogen Activation by Five-Electron Boron-Centered Radicals. Inorg Chem 2022; 61:2234-2241. [PMID: 35044758 DOI: 10.1021/acs.inorgchem.1c03546] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Due to the high bond dissociation energy (945 kJ mol-1) and the large highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap (10.8 eV), dinitrogen activation under mild conditions is extremely challenging. On the other hand, the conventional Haber-Bosch ammonia synthesis under harsh conditions consumes more than 1% of the world's annual energy supply. Thus, it is important and urgent to develop an alternative approach for dinitrogen activation under mild conditions. In comparison with transition metals, main group compounds are less explored for nitrogen activation. Here, we carry out density functional theory calculation to screen boron radicals for dinitrogen activation. As a result, the experimentally available seven-electron boron-centered radicals are found to be inactive to N2 activation, whereas some five-electron boron-centered radicals become favorable for dinitrogen activation, inviting experimental chemists' examination. The principal interacting spin-orbital analyses suggest that a five-electron boron-centered radical can mimic a transition metal on a synergic interaction with dinitrogen in the transition states.
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Affiliation(s)
- Jie Zeng
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Shicheng Dong
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Chenshu Dai
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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13
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Xu J, Xu X, Li D, Jian J. Spectroscopic Characterization of Two Boron Heterocyclic Radicals in the Solid Neon Matrix. Phys Chem Chem Phys 2022; 24:7961-7968. [DOI: 10.1039/d2cp00076h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two novel boron heterocyclic radicals, 3,4,5-trihydroborinine radical and 1-methyl-2-dihydro-1H-borole radical, were observed in the reaction of boron atom with cyclopentene. These radicals were trapped in solid neon and identified by...
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14
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Roesky HW, Nazish M, Ding Y, Legendre CM, Kumar A, Graw N, Schwederski B, Herbst-Irmer R, P P, Parameswaran P, Stalke D, Kaim W. High yield of a variety of silicon-boron radicals and their reactivity. Dalton Trans 2022; 51:11040-11047. [DOI: 10.1039/d2dt01318e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein we report stable silicon-boron radicals of composition LSi(NMe2)-B(Br)Tip (1), LSi(NMe2)-B(I)Tip (2) LSi(tBu)-B(I)Tip (3) [L=PhC(NtBu)2]. They were prepared in high yield using a one-pot reaction of LSiR, X2BTip, and KC8...
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15
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Sarcevic J, Heitkemper T, Sindlinger CP. Borole-based half-sandwich complexes of germanium and tin. Chem Commun (Camb) 2021; 58:246-249. [PMID: 34878448 DOI: 10.1039/d1cc06227a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis and initial observations regarding the reactivity of borole-based half-sandwich complexes with apical divalent group 14 elements germanium and tin are described. The 2,5-disilylborole substitution pattern allows their access via salt metathesis of the respective borole dianions.
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Affiliation(s)
- Julijan Sarcevic
- Insitut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstr. 4, D-37077 Göttingen, Germany
| | - Tobias Heitkemper
- Insitut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstr. 4, D-37077 Göttingen, Germany.,Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1a, D-52074 Aachen, Germany.
| | - Christian P Sindlinger
- Insitut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstr. 4, D-37077 Göttingen, Germany.,Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1a, D-52074 Aachen, Germany.
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16
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Wentz KE, Molino A, Freeman LA, Dickie DA, Wilson DJD, Gilliard RJ. Reactions of 9-Carbene-9-Borafluorene Monoanion and Selenium: Synthesis of Boryl-Substituted Selenides and Diselenides. Inorg Chem 2021; 60:13941-13949. [PMID: 34472333 DOI: 10.1021/acs.inorgchem.1c02124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reactions of 9-carbene-9-borafluorene monoanion (1) with elemental selenium and selenium-containing reagents are reported. When compound 1 is reacted with grey selenium in THF, various boryl-substituted selenides and diselenides are produced (2-6), including molecules resulting from migration of the carbene ligand Dipp group (Dipp = 2,6-diisopropylphenyl). However, when a similar reaction between 1 and grey selenium is performed in toluene in the presence of 18-crown-6, boryl-substituted selenide 7 is obtained as the sole boron-containing product. As compound 7 is the monomeric variant of organoselenide 3, 18-crown-6 promotes both product selectivity and solubility in a nonpolar solvent. Diselenide 5, which features a trans-bent B-Se-Se-B core, was directly isolated via reaction of 1 with Se2Cl2 in THF. Computational modeling suggests that the formation of 5 proceeds via a radical mechanism. This was supported by an experiment demonstrating that the CAAC-borafluorene radical also reacts with SeCl2 to yield 5 [CAAC = (2,6-diisopropylphenyl)-4,4-diethyl-2,2-dimethyl-pyrrolidin-5-ylidene]. Energy decomposition analysis of 5 indicates a covalent borafluorene-diselenide bond (ΔEint, -168.9 kcal mol-1). All of the new compounds were fully characterized via single-crystal X-ray diffraction and multinuclear nuclear magnetic resonance (1H, 13C, 11B, and 77Se).
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Affiliation(s)
- Kelsie E Wentz
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Andrew Molino
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia
| | - Lucas A Freeman
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Diane A Dickie
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - David J D Wilson
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia
| | - Robert J Gilliard
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
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17
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Abstract
Structurally authenticated free B-alkyl boroles are presented and electronic implications of alkyl substitution were assessed. Deprotonation of a boron-bound exocyclic methyl group in a B-methyl borole yields the first 5-boratafulvene anion-an isomer to boratabenzene. Boratafulvene was structurally characterized and its electronic structure probed by DFT calculations. The pKa value of the exocyclic B-CH3 in a set of boroles was computationally approximated and confirmed a pronounced acidic character caused by the boron atom embedded in an anti-aromatic moiety. The non-aromatic boratafulvene reacts as a C-centered nucleophile with the mild electrophile Me3 SnCl to give a stannylmethyl borole, regenerating the anti-aromaticity. As nucleophilic synthons for boroles, boratafulvenes thus open an entirely new avenue for synthetic strategies toward this highly reactive class of heterocycles. Boratafulvene reacts as a methylene transfer reagent in a bora-Wittig-type reaction generating a borole oxide.
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Affiliation(s)
- Tobias Heitkemper
- Institut für Anorganische ChemieGeorg-August-Universität GöttingenTammannstrasse 437077GöttingenGermany
| | - Leonard Naß
- Institut für Anorganische ChemieGeorg-August-Universität GöttingenTammannstrasse 437077GöttingenGermany
| | - Christian P. Sindlinger
- Institut für Anorganische ChemieGeorg-August-Universität GöttingenTammannstrasse 437077GöttingenGermany
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18
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Heitkemper T, Naß L, Sindlinger CP. Ein Boratafulven. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107968] [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)
- Tobias Heitkemper
- Institut für Anorganische Chemie Georg-August-Universität Göttingen Tammannstraße 4 37077 Göttingen Deutschland
| | - Leonard Naß
- Institut für Anorganische Chemie Georg-August-Universität Göttingen Tammannstraße 4 37077 Göttingen Deutschland
| | - Christian P. Sindlinger
- Institut für Anorganische Chemie Georg-August-Universität Göttingen Tammannstraße 4 37077 Göttingen Deutschland
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19
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Abstract
Boron-centred radicals (boryl radicals) are potential and attractive species in main group chemistry and synthetic chemistry. Recently, the development of boron compounds ligated by N-heterocyclic carbenes (NHCs) has sparked off advavnces in boryl radical chemistry because NHCs can highly stabilise boryl radicals by electronic and steric factors. This review highlights recent synthesis and reactions of such NHC-boryl radicals. From the standpoint of main group chemistry, examples of isolation or detection of unique NHC-boryl radicals are presented. From the standpoint of synthetic chemistry, on the other hand, the development of reactions of user-friendly NHC-boryl radicals, which has contributed to radical chemistry, organoboron chemistry and polymer science, is comprehensively described.
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Affiliation(s)
- Tsuyoshi Taniguchi
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
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20
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Wentz KE, Molino A, Weisflog SL, Kaur A, Dickie DA, Wilson DJD, Gilliard RJ. Stabilization of the Elusive 9-Carbene-9-Borafluorene Monoanion. Angew Chem Int Ed Engl 2021; 60:13065-13072. [PMID: 33780572 DOI: 10.1002/anie.202103628] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Indexed: 01/09/2023]
Abstract
Two-electron reduction of carbene-supported 9-bromo-9-borafluorenes with excess KC8 , Na, or Li-naphthalenide affords six N-heterocyclic carbene (NHC)- or cyclic(alkyl)(amino) carbene (CAAC)-stabilized borafluorene anions (3-8)-the first isolated and structurally authenticated examples of the elusive 9-carbene-9-borafluorene monoanion. The electronic structure, bonding, and aromaticity of the boracyclic anions were comprehensively investigated via computational studies. Compounds 5 and 8 react with metal halides via salt elimination to give new B-E (E=Au, Se, Ge)-containing materials (9-12). Upon reaction with diketones, the carbene ligand cleanly dissociates from 5 or 8 to yield new B-O containing spirocycles (13-14) that cannot be easily obtained using "normal" valent borafluorene compounds. Collectively, these results support the notion that carbene-stabilized monoanionic borafluorenes may serve as a new platform for the one-step construction of higher-value boracyclic materials.
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Affiliation(s)
- Kelsie E Wentz
- Department of Chemistry, University of Virginia, 409 McCormick Rd./ PO Box 400319, Charlottesville, VA, 22904, USA
| | - Andrew Molino
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, Latrobe University, Melbourne, 3086, Victoria, Australia
| | - Sarah L Weisflog
- Department of Chemistry, University of Virginia, 409 McCormick Rd./ PO Box 400319, Charlottesville, VA, 22904, USA
| | - Aishvaryadeep Kaur
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, Latrobe University, Melbourne, 3086, Victoria, Australia
| | - Diane A Dickie
- Department of Chemistry, University of Virginia, 409 McCormick Rd./ PO Box 400319, Charlottesville, VA, 22904, USA
| | - David J D Wilson
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, Latrobe University, Melbourne, 3086, Victoria, Australia
| | - Robert J Gilliard
- Department of Chemistry, University of Virginia, 409 McCormick Rd./ PO Box 400319, Charlottesville, VA, 22904, USA
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21
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Wentz KE, Molino A, Weisflog SL, Kaur A, Dickie DA, Wilson DJD, Gilliard RJ. Stabilization of the Elusive 9‐Carbene‐9‐Borafluorene Monoanion. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202103628] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Kelsie E. Wentz
- Department of Chemistry University of Virginia 409 McCormick Rd./ PO Box 400319 Charlottesville VA 22904 USA
| | - Andrew Molino
- Department of Chemistry and Physics La Trobe Institute for Molecular Science Latrobe University Melbourne 3086 Victoria Australia
| | - Sarah L. Weisflog
- Department of Chemistry University of Virginia 409 McCormick Rd./ PO Box 400319 Charlottesville VA 22904 USA
| | - Aishvaryadeep Kaur
- Department of Chemistry and Physics La Trobe Institute for Molecular Science Latrobe University Melbourne 3086 Victoria Australia
| | - Diane A. Dickie
- Department of Chemistry University of Virginia 409 McCormick Rd./ PO Box 400319 Charlottesville VA 22904 USA
| | - David J. D. Wilson
- Department of Chemistry and Physics La Trobe Institute for Molecular Science Latrobe University Melbourne 3086 Victoria Australia
| | - Robert J. Gilliard
- Department of Chemistry University of Virginia 409 McCormick Rd./ PO Box 400319 Charlottesville VA 22904 USA
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22
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Beerhues J, Neubrand M, Sobottka S, Neuman NI, Aberhan H, Chandra S, Sarkar B. Directed Design of a Au I Complex with a Reduced Mesoionic Carbene Radical Ligand: Insights from 1,2,3-Triazolylidene Selenium Adducts and Extensive Electrochemical Investigations. Chemistry 2021; 27:6557-6568. [PMID: 33502818 PMCID: PMC8252451 DOI: 10.1002/chem.202100105] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Indexed: 11/07/2022]
Abstract
Carbene-based radicals are important for both fundamental and applied chemical research. Herein, extensive electrochemical investigations of nine different 1,2,3-triazolylidene selenium adducts are reported. It is found that the half-wave potentials of the first reduction of the selones correlate with their calculated LUMO levels and the LUMO levels of the corresponding triazolylidene-based mesoionic carbenes (MICs). Furthermore, unexpected quasi-reversibility of the reduction of two triazoline selones, exhibiting comparable reduction potentials, was discovered. Through UV/Vis/NIR and EPR spectroelectrochemical investigations supported by DFT calculations, the radical anion was unambiguously assigned to be triazoline centered. This electrochemical behavior was transferred to a triazolylidene-type MIC-gold phenyl complex resulting in a MIC-radical coordinated AuI species. Apart from UV-Vis-NIR and EPR spectroelectrochemical investigations of the reduction, the reduced gold-coordinated MIC radical complex was also formed in situ in the bulk through chemical reduction. This is the first report of a monodentate triazolylidene-based MIC ligand that can be reduced to its anion radical in a metal complex. The results presented here provide design principles for stabilizing radicals based on MICs.
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Affiliation(s)
- Julia Beerhues
- Lehrstuhl für Anorganische KoordinationschemieInstitut für Anorganische ChemieUniversität StuttgartPfaffenwaldring 5570569StuttgartGermany
- Institut für Chemie und BiochemieFreie Universität BerlinFabeckstraße 34–3614195BerlinGermany
| | - Maren Neubrand
- Lehrstuhl für Anorganische KoordinationschemieInstitut für Anorganische ChemieUniversität StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Sebastian Sobottka
- Institut für Chemie und BiochemieFreie Universität BerlinFabeckstraße 34–3614195BerlinGermany
| | - Nicolás I. Neuman
- Lehrstuhl für Anorganische KoordinationschemieInstitut für Anorganische ChemieUniversität StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Hannes Aberhan
- Institut für Chemie und BiochemieFreie Universität BerlinFabeckstraße 34–3614195BerlinGermany
| | - Shubhadeep Chandra
- Lehrstuhl für Anorganische KoordinationschemieInstitut für Anorganische ChemieUniversität StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Biprajit Sarkar
- Lehrstuhl für Anorganische KoordinationschemieInstitut für Anorganische ChemieUniversität StuttgartPfaffenwaldring 5570569StuttgartGermany
- Institut für Chemie und BiochemieFreie Universität BerlinFabeckstraße 34–3614195BerlinGermany
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23
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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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24
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Budy H, Gilmer J, Trageser T, Wagner M. Anionic Organoboranes: Delicate Flowers Worth Caring for. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000786] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Hendrik Budy
- Institut für Anorganische Chemie Goethe‐Universität Frankfurt Max‐von‐Laue‐Str. 7 60438 Frankfurt (Main) Germany
| | - Jannik Gilmer
- Institut für Anorganische Chemie Goethe‐Universität Frankfurt Max‐von‐Laue‐Str. 7 60438 Frankfurt (Main) Germany
| | - Timo Trageser
- Institut für Anorganische Chemie Goethe‐Universität Frankfurt Max‐von‐Laue‐Str. 7 60438 Frankfurt (Main) Germany
| | - Matthias Wagner
- Institut für Anorganische Chemie Goethe‐Universität Frankfurt Max‐von‐Laue‐Str. 7 60438 Frankfurt (Main) Germany
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25
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Abstract
This work describes the synthesis and characterization of a highly reactive cationic borole. Halide abstraction with Li{Al[OC(CF3 )3 ]4 } from the NHC-chloroborole adduct yields the first stable NHC-supported 1-(Me NHC)-2,5-(SiMe3 )2 -3,4-(Ph*)2 -borole cation. Electronically, it features both a five-membered cyclic conjugated 4 π-electron system and a cationic charge and thus resembles the yet elusive cyclopentadienyl cation. The borole cation was characterized crystallographically, spectroscopically (NMR, UV/Vis), by cyclovoltammetry, microanalysis and mass-spectrometry and its electronic structure was probed computationally. The cation reacts with tolane and reversibly binds carbon monoxide. Direct comparison with the structurally related, yet neutral, 1-mesityl borole reveals strong Lewis acidity, reduced HOMO-LUMO gaps, and increased anti-aromatic character.
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Affiliation(s)
- Tobias Heitkemper
- Institut für Anorganische ChemieGeorg-August-Universität GöttingenTammannstr. 437077GöttingenGermany
| | - Christian P. Sindlinger
- Institut für Anorganische ChemieGeorg-August-Universität GöttingenTammannstr. 437077GöttingenGermany
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26
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Jian J, Wu X, Chen M, Zhou M. Boron-Mediated Carbon-Carbon Bond Cleavage and Rearrangement of Benzene Forming the Borepinyl Radical and Borole Derivatives. J Am Chem Soc 2020; 142:10079-10086. [PMID: 32383858 DOI: 10.1021/jacs.0c02131] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The reaction of atomic boron with benzene in solid neon has been investigated by matrix isolation infrared spectroscopy with isotopic substitutions as well as quantum chemical calculations. The reaction is initiated by boron atom addition to benzene in forming an η2-(1, 4) π adduct (A). A borepinyl radical (B) formed by C-C bond insertion is also observed on annealing. The η2-(1,4) π adduct photoisomerizes to an unprecedented borole substituted vinyl radical intermediate (C) via ring-opening and rearrangement reactions involving an antiaromatic borole subunit. A previously unconsidered 1-ethynyl-2-dihydro-1H-borole radical (D) is generated as the final product under UV light irradiation. The results presented herein give new insight into the benzene carbon-carbon bond cleavage and rearrangement reactions mediated by a nonmetal and provide a possible route for the construction of heterocyclic borepinyl and borole species via benzene ring opening and rearrangement reactions.
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Affiliation(s)
- Jiwen Jian
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, China
| | - Xuan Wu
- Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative materials, Fudan University, Shanghai 200433, China
| | - Mohua Chen
- Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative materials, Fudan University, Shanghai 200433, China
| | - Mingfei Zhou
- Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative materials, Fudan University, Shanghai 200433, China
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27
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Feng Z, Fang Y, Ruan H, Zhao Y, Tan G, Wang X. Stable Radical Cation and Dication of an N‐Heterocyclic Carbene Stabilized Digallene: Synthesis, Characterization and Reactivity. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202000051] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Zhongtao Feng
- State Key Laboratory of Coordination ChemistryJiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringCollaborative Innovation Center of Advanced MicrostructuresNanjing University Nanjing 210023 P. R. China
| | - Yong Fang
- State Key Laboratory of Coordination ChemistryJiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringCollaborative Innovation Center of Advanced MicrostructuresNanjing University Nanjing 210023 P. R. China
| | - Huapeng Ruan
- State Key Laboratory of Coordination ChemistryJiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringCollaborative Innovation Center of Advanced MicrostructuresNanjing University Nanjing 210023 P. R. China
| | - Yue Zhao
- State Key Laboratory of Coordination ChemistryJiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringCollaborative Innovation Center of Advanced MicrostructuresNanjing University Nanjing 210023 P. R. China
| | - Gengwen Tan
- State Key Laboratory of Coordination ChemistryJiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringCollaborative Innovation Center of Advanced MicrostructuresNanjing University Nanjing 210023 P. R. China
- College of Chemistry, Chemical Engineering and Materials ScienceSoochow University Suzhou 215123 P. R. China
| | - Xinping Wang
- State Key Laboratory of Coordination ChemistryJiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringCollaborative Innovation Center of Advanced MicrostructuresNanjing University Nanjing 210023 P. R. China
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28
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Feng Z, Fang Y, Ruan H, Zhao Y, Tan G, Wang X. Stable Radical Cation and Dication of an N-Heterocyclic Carbene Stabilized Digallene: Synthesis, Characterization and Reactivity. Angew Chem Int Ed Engl 2020; 59:6769-6774. [PMID: 31994317 DOI: 10.1002/anie.202000051] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Indexed: 11/06/2022]
Abstract
One- and two-electron oxidation of a digallene stabilized by an N-heterocyclic carbene afforded the first stable gallium-based radical cation and dication salts, respectively. Structural analysis and theoretical calculations reveal that the oxidation occurs at the Ga=Ga double bond, leading to removal of π electrons of the double bond and a decrease of the bond order. The spin density of the radical cation mainly locates at the two gallium centers as demonstrated by EPR spectroscopy and theoretical calculations. Moreover, the reactivity of the radical cation salt toward nBu3 SnH and cyclo-S8 was studied; a digallium-hydride cation salt containing a Ga-Ga single bond and a gallium sulfide cluster bearing an unprecedented ladder-like Ga4 S4 core structure were obtained, respectively.
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Affiliation(s)
- Zhongtao Feng
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
| | - Yong Fang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
| | - Huapeng Ruan
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
| | - Yue Zhao
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
| | - Gengwen Tan
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China.,College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P. R. China
| | - Xinping Wang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
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29
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Gilmer J, Budy H, Kaese T, Bolte M, Lerner H, Wagner M. The 9H-9-Borafluorene Dianion: A Surrogate for Elusive Diarylboryl Anion Nucleophiles. Angew Chem Int Ed Engl 2020; 59:5621-5625. [PMID: 31834978 PMCID: PMC7155136 DOI: 10.1002/anie.201914219] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Indexed: 11/13/2022]
Abstract
Double reduction of the THF adduct of 9H-9-borafluorene (1⋅THF) with excess alkali metal affords the dianion salts M2 [1] in essentially quantitative yields (M=Li-K). Even though the added charge is stabilized through π delocalization, [1]2- acts as a formal boron nucleophile toward organoboron (1⋅THF) and tetrel halide electrophiles (MeCl, Et3 SiCl, Me3 SnCl) to form B-B/C/Si/Sn bonds. The substrate dependence of open-shell versus closed-shell pathways has been investigated.
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Affiliation(s)
- Jannik Gilmer
- Institut für Anorganische ChemieGoethe-Universität FrankfurtMax-von-Laue-Strasse 760438Frankfurt (Main)Germany
| | - Hendrik Budy
- Institut für Anorganische ChemieGoethe-Universität FrankfurtMax-von-Laue-Strasse 760438Frankfurt (Main)Germany
| | - Thomas Kaese
- Institut für Anorganische ChemieGoethe-Universität FrankfurtMax-von-Laue-Strasse 760438Frankfurt (Main)Germany
| | - Michael Bolte
- Institut für Anorganische ChemieGoethe-Universität FrankfurtMax-von-Laue-Strasse 760438Frankfurt (Main)Germany
| | - Hans‐Wolfram Lerner
- Institut für Anorganische ChemieGoethe-Universität FrankfurtMax-von-Laue-Strasse 760438Frankfurt (Main)Germany
| | - Matthias Wagner
- Institut für Anorganische ChemieGoethe-Universität FrankfurtMax-von-Laue-Strasse 760438Frankfurt (Main)Germany
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30
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Yang W, Krantz KE, Freeman LA, Dickie DA, Molino A, Frenking G, Pan S, Wilson DJD, Gilliard RJ. Persistent Borafluorene Radicals. Angew Chem Int Ed Engl 2020; 59:3850-3854. [PMID: 31816143 PMCID: PMC7064902 DOI: 10.1002/anie.201909627] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/19/2019] [Indexed: 01/23/2023]
Abstract
N‐Heterocyclic carbene (NHC)‐ and cyclic (alkyl)(amino)carbene (CAAC)‐stabilized borafluorene radicals have been isolated and characterized by elemental analysis, single‐crystal X‐ray diffraction, UV/Vis absorption, cyclic voltammetry (CV), electron paramagnetic resonance (EPR) spectroscopy, and theoretical studies. Both the CAAC–borafluorene radical (2) and the NHC–borafluorene radical (4) have a considerable amount of spin density localized on the boron atoms (0.322 for 2 and 0.369 for 4). In compound 2, the unpaired electron is also partly delocalized over the CAAC ligand carbeneC and N atoms. However, the unpaired electron in compound 4 mainly resides throughout the borafluorene π‐system, with significantly less delocalization over the NHC ligand. These results highlight the Lewis base dependent electrostructural tuning of materials‐relevant radicals. Notably, this is the first report of crystalline borafluorene radicals, and these species exhibit remarkable solid‐state and solution stability.
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Affiliation(s)
- Wenlong Yang
- Department of Chemistry, University of Virginia, 409 McCormick Rd./ PO Box 400319, Charlottesville, VA, 22904, USA
| | - Kelsie E Krantz
- Department of Chemistry, University of Virginia, 409 McCormick Rd./ PO Box 400319, Charlottesville, VA, 22904, USA
| | - Lucas A Freeman
- Department of Chemistry, University of Virginia, 409 McCormick Rd./ PO Box 400319, Charlottesville, VA, 22904, USA
| | - Diane A Dickie
- Department of Chemistry, University of Virginia, 409 McCormick Rd./ PO Box 400319, Charlottesville, VA, 22904, USA
| | - Andrew Molino
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Victoria, Australia
| | - Gernot Frenking
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35043, Marburg, Germany
| | - Sudip Pan
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35043, Marburg, Germany
| | - David J D Wilson
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Victoria, Australia
| | - Robert J Gilliard
- Department of Chemistry, University of Virginia, 409 McCormick Rd./ PO Box 400319, Charlottesville, VA, 22904, USA
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31
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Yang W, Krantz KE, Freeman LA, Dickie DA, Molino A, Frenking G, Pan S, Wilson DJD, Gilliard RJ. Persistent Borafluorene Radicals. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201909627] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Wenlong Yang
- Department of Chemistry University of Virginia 409 McCormick Rd./ PO Box 400319 Charlottesville VA 22904 USA
| | - Kelsie E. Krantz
- Department of Chemistry University of Virginia 409 McCormick Rd./ PO Box 400319 Charlottesville VA 22904 USA
| | - Lucas A. Freeman
- Department of Chemistry University of Virginia 409 McCormick Rd./ PO Box 400319 Charlottesville VA 22904 USA
| | - Diane A. Dickie
- Department of Chemistry University of Virginia 409 McCormick Rd./ PO Box 400319 Charlottesville VA 22904 USA
| | - Andrew Molino
- Department of Chemistry and Physics La Trobe Institute for Molecular Science La Trobe University Melbourne 3086 Victoria Australia
| | - Gernot Frenking
- Fachbereich Chemie Philipps-Universität Marburg Hans-Meerwein-Straße 35043 Marburg Germany
| | - Sudip Pan
- Fachbereich Chemie Philipps-Universität Marburg Hans-Meerwein-Straße 35043 Marburg Germany
| | - David J. D. Wilson
- Department of Chemistry and Physics La Trobe Institute for Molecular Science La Trobe University Melbourne 3086 Victoria Australia
| | - Robert J. Gilliard
- Department of Chemistry University of Virginia 409 McCormick Rd./ PO Box 400319 Charlottesville VA 22904 USA
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32
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Gilmer J, Budy H, Kaese T, Bolte M, Lerner H, Wagner M. The 9
H
‐9‐Borafluorene Dianion: A Surrogate for Elusive Diarylboryl Anion Nucleophiles. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201914219] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Jannik Gilmer
- Institut für Anorganische Chemie Goethe-Universität Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Hendrik Budy
- Institut für Anorganische Chemie Goethe-Universität Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Thomas Kaese
- Institut für Anorganische Chemie Goethe-Universität Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Michael Bolte
- Institut für Anorganische Chemie Goethe-Universität Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Hans‐Wolfram Lerner
- Institut für Anorganische Chemie Goethe-Universität Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Matthias Wagner
- Institut für Anorganische Chemie Goethe-Universität Frankfurt Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
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33
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Rohman SS, Sarmah B, Borthakur B, Remya GS, Suresh CH, Phukan AK. Extending the Library of Boron Bases: A Contribution from Theory. Organometallics 2019. [DOI: 10.1021/acs.organomet.9b00317] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Bikash Sarmah
- Department of Chemical Sciences, Tezpur University, Napaam 784028, Assam India
| | - Bitupon Borthakur
- Department of Chemical Sciences, Tezpur University, Napaam 784028, Assam India
| | - Geetha S. Remya
- Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum, Kerala 695 019, India
| | - Cherumuttathu H. Suresh
- Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum, Kerala 695 019, India
| | - Ashwini K. Phukan
- Department of Chemical Sciences, Tezpur University, Napaam 784028, Assam India
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34
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Vallet AL, Lacôte E. Thiolation of NHC-boranes: influence of the substitution at boron. Org Biomol Chem 2019; 17:4234-4237. [PMID: 30951071 DOI: 10.1039/c9ob00578a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Several N-Heterocyclic Carbene (NHC)-boryl sulfides with B-substituents were prepared. The added steric hindrance leads to much improved selectivities as only the NHC-boryl mono-sulfides were obtained. The B-substituted NHC-boranes are also conducive to more selective S to N NHC-boryl shift, provided that the NHC used is not too sterically demanding.
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Affiliation(s)
- Anne-Laure Vallet
- ICSN-CNRS, Bâtiment 27, 1 avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France
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35
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Doddi A, Peters M, Tamm M. N-Heterocyclic Carbene Adducts of Main Group Elements and Their Use as Ligands in Transition Metal Chemistry. Chem Rev 2019; 119:6994-7112. [PMID: 30983327 DOI: 10.1021/acs.chemrev.8b00791] [Citation(s) in RCA: 302] [Impact Index Per Article: 60.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
N-Heterocyclic carbenes (NHC) are nowadays ubiquitous and indispensable in many research fields, and it is not possible to imagine modern transition metal and main group element chemistry without the plethora of available NHCs with tailor-made electronic and steric properties. While their suitability to act as strong ligands toward transition metals has led to numerous applications of NHC complexes in homogeneous catalysis, their strong σ-donating and adaptable π-accepting abilities have also contributed to an impressive vitalization of main group chemistry with the isolation and characterization of NHC adducts of almost any element. Formally, NHC coordination to Lewis acids affords a transfer of nucleophilicity from the carbene carbon atom to the attached exocyclic moiety, and low-valent and low-coordinate adducts of the p-block elements with available lone pairs and/or polarized carbon-element π-bonds are able to act themselves as Lewis basic donor ligands toward transition metals. Accordingly, the availability of a large number of novel NHC adducts has not only produced new varieties of already existing ligand classes but has also allowed establishment of numerous complexes with unusual and often unprecedented element-metal bonds. This review aims at summarizing this development comprehensively and covers the usage of N-heterocyclic carbene adducts of the p-block elements as ligands in transition metal chemistry.
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Affiliation(s)
- Adinarayana Doddi
- Technische Universität Braunschweig, Institut für Anorganische und Analytische Chemie, Hagenring 30, 38106 Braunschweig, Germany
| | - Marius Peters
- Technische Universität Braunschweig, Institut für Anorganische und Analytische Chemie, Hagenring 30, 38106 Braunschweig, Germany
| | - Matthias Tamm
- Technische Universität Braunschweig, Institut für Anorganische und Analytische Chemie, Hagenring 30, 38106 Braunschweig, Germany
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36
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Kundu S, Sinhababu S, Chandrasekhar V, Roesky HW. Stable cyclic (alkyl)(amino)carbene (cAAC) radicals with main group substituents. Chem Sci 2019; 10:4727-4741. [PMID: 31160949 PMCID: PMC6510188 DOI: 10.1039/c9sc01351b] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 04/06/2019] [Indexed: 11/21/2022] Open
Abstract
Recent attempts to isolate cyclic (alkyl)(amino)carbene stabilized radicals of p-block elements have been described here.
Isolation and characterization of stable radicals has been a long-pursued quest. While there has been some progress in this field particularly with respect to carbon, radicals involving heavier p-block elements are still considerably sparse. In this review we describe our recent successful efforts on the isolation of stable p-block element radicals particularly those involving aluminum, silicon, and phosphorus.
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Affiliation(s)
- Subrata Kundu
- Universität Göttingen , Institut für Anorganische Chemie , Tammannstrasse 4 , D-37077 , Göttingen , Germany .
| | - Soumen Sinhababu
- Universität Göttingen , Institut für Anorganische Chemie , Tammannstrasse 4 , D-37077 , Göttingen , Germany .
| | - Vadapalli Chandrasekhar
- Universität Göttingen , Institut für Anorganische Chemie , Tammannstrasse 4 , D-37077 , Göttingen , Germany . .,Tata Institute of Fundamental Research Hyderabad , Hyderabad 500107 , India.,Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur 208016 , India .
| | - Herbert W Roesky
- Universität Göttingen , Institut für Anorganische Chemie , Tammannstrasse 4 , D-37077 , Göttingen , Germany .
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37
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Essex LA, Taylor JW, Harman WH. Nickel complexes of phosphine-appended benzannulated boron heterocycles. Tetrahedron 2019. [DOI: 10.1016/j.tet.2019.02.047] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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38
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Goettel JT, Braunschweig H. Recent advances in boron-centered ligands and their transition metal complexes. Coord Chem Rev 2019. [DOI: 10.1016/j.ccr.2018.09.013] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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39
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Deissenberger A, Welz E, Drescher R, Krummenacher I, Dewhurst RD, Engels B, Braunschweig H. A New Class of Neutral Boron‐Based Diradicals Spanned by a Two‐Carbon‐Atom Bridge. Angew Chem Int Ed Engl 2019; 58:1842-1846. [DOI: 10.1002/anie.201813335] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Indexed: 11/12/2022]
Affiliation(s)
- Andrea Deissenberger
- Institute for Inorganic ChemistryJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Eileen Welz
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Regina Drescher
- Institute for Inorganic ChemistryJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Ivo Krummenacher
- Institute for Inorganic ChemistryJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Rian D. Dewhurst
- Institute for Inorganic ChemistryJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Bernd Engels
- Institute for Physical and Theoretical ChemistryJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Holger Braunschweig
- Institute for Inorganic ChemistryJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
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40
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Deissenberger A, Welz E, Drescher R, Krummenacher I, Dewhurst RD, Engels B, Braunschweig H. Eine neue Strukturklasse neutraler borhaltiger Diradikale verbrückt über zwei Kohlenstoffatome. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201813335] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Andrea Deissenberger
- Institut für Anorganische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit BorJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Eileen Welz
- Institut für Physikalische und Theoretische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Regina Drescher
- Institut für Anorganische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit BorJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Ivo Krummenacher
- Institut für Anorganische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit BorJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Rian D. Dewhurst
- Institut für Anorganische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit BorJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Bernd Engels
- Institut für Physikalische und Theoretische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Holger Braunschweig
- Institut für Anorganische ChemieJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für nachhaltige Chemie & Katalyse mit BorJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
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41
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Kim Y, Lee E. Stable Organic Radicals Derived from N‐Heterocyclic Carbenes. Chemistry 2018; 24:19110-19121. [PMID: 30058298 DOI: 10.1002/chem.201801560] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/23/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Youngsuk Kim
- Center for Self-assembly and ComplexityInstitute for Basic Science (IBS) Pohang 37673 Republic of Korea
- Department of ChemistryPohang University of Science and Technology Pohang 37673 Republic of Korea
| | - Eunsung Lee
- Center for Self-assembly and ComplexityInstitute for Basic Science (IBS) Pohang 37673 Republic of Korea
- Department of ChemistryPohang University of Science and Technology Pohang 37673 Republic of Korea
- Division of Advanced Materials SciencePohang University of Science and Technology Pohang 37673 Republic of Korea
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42
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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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43
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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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44
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Chung MH, Yu IF, Liu YH, Lin TS, Peng SM, Chiu CW. Destabilizing Character of a π-Conjugated Boron Center in Bisphenol Radicals. Inorg Chem 2018; 57:11732-11737. [PMID: 30179003 DOI: 10.1021/acs.inorgchem.8b01865] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although boron-containing radicals are promising materials for molecular electronic devices, the electronic effect of the σ-donating yet π-accepting boron center on the stability of open-shell species has been less discussed. In this work, the role of a tricoordinate boron center in π-conjugated radicals was explored through electron paramagnetic resonance measurement of several boron-linked bisphenol radicals and diradicals. Replacing the bridging methine fragment of a neutral Galvinoxyl radical with an arylboryl group led to the corresponding boron-linked radical anion that requires excessive steric protection at the boron center to be persistent in solution. Experimental and theoretical investigations revealed that the introduction of boron would diminish the quinoidal character of the phenoxyl radical and increase both the electrophilicity and nucleophilicity of the open-shell species. Therefore, it is important to consider the steric protection of the boron center in boron-containing π-conjugated organic radicals.
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Affiliation(s)
- Ming-Han Chung
- Department of Chemistry , National Taiwan University , No. 1, Section 4, Roosevelt Road , Taipei 10617 , Taiwan
| | - Isaac Furay Yu
- Department of Chemistry , National Taiwan University , No. 1, Section 4, Roosevelt Road , Taipei 10617 , Taiwan
| | - Yi-Hung Liu
- Department of Chemistry , National Taiwan University , No. 1, Section 4, Roosevelt Road , Taipei 10617 , Taiwan
| | - Tien-Sung Lin
- Department of Chemistry , National Taiwan University , No. 1, Section 4, Roosevelt Road , Taipei 10617 , Taiwan
| | - Shie-Ming Peng
- Department of Chemistry , National Taiwan University , No. 1, Section 4, Roosevelt Road , Taipei 10617 , Taiwan
| | - Ching-Wen Chiu
- Department of Chemistry , National Taiwan University , No. 1, Section 4, Roosevelt Road , Taipei 10617 , Taiwan
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45
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Roy DK, Krummenacher I, Stennett TE, Lenczyk C, Thiess T, Welz E, Engels B, Braunschweig H. Selective one- and two-electron reductions of a haloborane enabled by a π-withdrawing carbene ligand. Chem Commun (Camb) 2018; 54:9015-9018. [PMID: 30046799 DOI: 10.1039/c8cc03433h] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
A carbene-stabilised neutral boryl radical and a boryl anion are isolated via selective one- and two-electron reduction of a diamidocarbene (DAC) adduct of dibromo(pentafluorophenyl)borane. Both the radical and the anion have been characterised by various spectroscopic techniques in solution, while the structures have been ascertained by single-crystal X-ray diffraction. In contrast, the reduction of the analogous cyclic (alkyl)(amino) carbene (CAAC) adduct yields a C-H activation product.
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Affiliation(s)
- Dipak Kumar Roy
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany. and 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. and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Tom E Stennett
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany. and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Carsten Lenczyk
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany. and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Torsten Thiess
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany. and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Eileen Welz
- Institute for Physical and Theoretical Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Bernd Engels
- Institute for Physical and Theoretical Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Holger Braunschweig
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany. and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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Subervie D, Graff B, Nerkar S, Curran DP, Lalevée J, Lacôte E. Difluorination at Boron Leads to the First Electrophilic Ligated Boryl Radical (NHC‐BF
2
.
). Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201806476] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Daniel Subervie
- Univ Lyon Université Claude Bernard Lyon 1 CNRS, CNES, ArianeGroup, LHCEP Bât. Raulin, 2 rue Victor Grignard 69622 Villeurbanne France
| | - Bernadette Graff
- Institut de Science des Matériaux de Mulhouse (IS2M), UMR CNRS 7361 Université de Haute Alsace 15 rue Jean Starcky 68057 Mulhouse France
| | - Swapnil Nerkar
- Department of Chemistry University of Pittsburgh Pittsburgh PA 15260 USA
| | - Dennis P. Curran
- Department of Chemistry University of Pittsburgh Pittsburgh PA 15260 USA
| | - Jacques Lalevée
- Institut de Science des Matériaux de Mulhouse (IS2M), UMR CNRS 7361 Université de Haute Alsace 15 rue Jean Starcky 68057 Mulhouse France
| | - Emmanuel Lacôte
- Univ Lyon Université Claude Bernard Lyon 1 CNRS, CNES, ArianeGroup, LHCEP Bât. Raulin, 2 rue Victor Grignard 69622 Villeurbanne France
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47
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Subervie D, Graff B, Nerkar S, Curran DP, Lalevée J, Lacôte E. Difluorination at Boron Leads to the First Electrophilic Ligated Boryl Radical (NHC-BF 2. ). Angew Chem Int Ed Engl 2018; 57:10251-10256. [PMID: 29928777 DOI: 10.1002/anie.201806476] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Indexed: 11/10/2022]
Abstract
1,3-Dimethylimidazol-2-ylidene difluoroborane (NHC-BF2 H) was prepared in a one-pot, two-step reaction from the parent ligated borane (NHC-BH3 ). The derived difluoroboryl radical (NHC-BF2. ) was generated by laser flash photolysis experiments and characterized by UV spectroscopy and rate-constant measurements. It is transient and reacts quickly with O2 . Unusually, it also reacts more rapidly with ethyl vinyl ether than with methyl acrylate. By this measure, it is the first electrophilic ligated boryl radical. Both NHC-BH3 and NHC-BF2 H serve as co-initiators in bulk photopolymerizations, converting both electron-poor and electron-rich monomers at roughly similar rates. However, the difluorinated coinitiator provides polymers with dramatically increased chain lengths from both monomers.
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Affiliation(s)
- Daniel Subervie
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, CNES, ArianeGroup, LHCEP, Bât. Raulin, 2 rue Victor Grignard, 69622, Villeurbanne, France
| | - Bernadette Graff
- Institut de Science des Matériaux de Mulhouse (IS2M), UMR CNRS 7361, Université de Haute Alsace, 15 rue Jean Starcky, 68057, Mulhouse, France
| | - Swapnil Nerkar
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Dennis P Curran
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Jacques Lalevée
- Institut de Science des Matériaux de Mulhouse (IS2M), UMR CNRS 7361, Université de Haute Alsace, 15 rue Jean Starcky, 68057, Mulhouse, France
| | - Emmanuel Lacôte
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, CNES, ArianeGroup, LHCEP, Bât. Raulin, 2 rue Victor Grignard, 69622, Villeurbanne, France
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48
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Nesterov V, Reiter D, Bag P, Frisch P, Holzner R, Porzelt A, Inoue S. NHCs in Main Group Chemistry. Chem Rev 2018; 118:9678-9842. [PMID: 29969239 DOI: 10.1021/acs.chemrev.8b00079] [Citation(s) in RCA: 518] [Impact Index Per Article: 86.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Since the discovery of the first stable N-heterocyclic carbene (NHC) in the beginning of the 1990s, these divalent carbon species have become a common and available class of compounds, which have found numerous applications in academic and industrial research. Their important role as two-electron donor ligands, especially in transition metal chemistry and catalysis, is difficult to overestimate. In the past decade, there has been tremendous research attention given to the chemistry of low-coordinate main group element compounds. Significant progress has been achieved in stabilization and isolation of such species as Lewis acid/base adducts with highly tunable NHC ligands. This has allowed investigation of numerous novel types of compounds with unique electronic structures and opened new opportunities in the rational design of novel organic catalysts and materials. This Review gives a general overview of this research, basic synthetic approaches, key features of NHC-main group element adducts, and might be useful for the broad research community.
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Affiliation(s)
- Vitaly Nesterov
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center , Technische Universität München , Lichtenbergstrasse 4 , Garching bei München 85748 , Germany
| | - Dominik Reiter
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center , Technische Universität München , Lichtenbergstrasse 4 , Garching bei München 85748 , Germany
| | - Prasenjit Bag
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center , Technische Universität München , Lichtenbergstrasse 4 , Garching bei München 85748 , Germany
| | - Philipp Frisch
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center , Technische Universität München , Lichtenbergstrasse 4 , Garching bei München 85748 , Germany
| | - Richard Holzner
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center , Technische Universität München , Lichtenbergstrasse 4 , Garching bei München 85748 , Germany
| | - Amelie Porzelt
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center , Technische Universität München , Lichtenbergstrasse 4 , Garching bei München 85748 , Germany
| | - Shigeyoshi Inoue
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center , Technische Universität München , Lichtenbergstrasse 4 , Garching bei München 85748 , Germany
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49
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Wang B, Li Y, Ganguly R, Webster RD, Kinjo R. A Crystalline Diazadiborinine Radical Cation and Its Boron-Centered Radical Reactivity. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201803547] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Baolin Wang
- Division of Chemistry and Biological Chemistry; School of Physical and Mathematical Sciences; Nanyang Technological University; Nanyang Link 21 Singapore 637371 Singapore
| | - Yongxin Li
- Division of Chemistry and Biological Chemistry; School of Physical and Mathematical Sciences; Nanyang Technological University; Nanyang Link 21 Singapore 637371 Singapore
| | - Rakesh Ganguly
- Division of Chemistry and Biological Chemistry; School of Physical and Mathematical Sciences; Nanyang Technological University; Nanyang Link 21 Singapore 637371 Singapore
| | - Richard D. Webster
- Division of Chemistry and Biological Chemistry; School of Physical and Mathematical Sciences; Nanyang Technological University; Nanyang Link 21 Singapore 637371 Singapore
| | - Rei Kinjo
- Division of Chemistry and Biological Chemistry; School of Physical and Mathematical Sciences; Nanyang Technological University; Nanyang Link 21 Singapore 637371 Singapore
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50
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Wang B, Li Y, Ganguly R, Webster RD, Kinjo R. A Crystalline Diazadiborinine Radical Cation and Its Boron-Centered Radical Reactivity. Angew Chem Int Ed Engl 2018; 57:7826-7829. [DOI: 10.1002/anie.201803547] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Baolin Wang
- Division of Chemistry and Biological Chemistry; School of Physical and Mathematical Sciences; Nanyang Technological University; Nanyang Link 21 Singapore 637371 Singapore
| | - Yongxin Li
- Division of Chemistry and Biological Chemistry; School of Physical and Mathematical Sciences; Nanyang Technological University; Nanyang Link 21 Singapore 637371 Singapore
| | - Rakesh Ganguly
- Division of Chemistry and Biological Chemistry; School of Physical and Mathematical Sciences; Nanyang Technological University; Nanyang Link 21 Singapore 637371 Singapore
| | - Richard D. Webster
- Division of Chemistry and Biological Chemistry; School of Physical and Mathematical Sciences; Nanyang Technological University; Nanyang Link 21 Singapore 637371 Singapore
| | - Rei Kinjo
- Division of Chemistry and Biological Chemistry; School of Physical and Mathematical Sciences; Nanyang Technological University; Nanyang Link 21 Singapore 637371 Singapore
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