1
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Pahar S, van Ingen Y, Babaahmadi R, Kariuki BM, Wirth T, Richards E, Melen RL. Diverse Reactivity of Amidinate-Supported Boron Centers with the Hypersilyl Anion and Access to a Monomeric Secondary Boron Hydride. Inorg Chem 2024; 63:8302-8311. [PMID: 38652816 PMCID: PMC11080068 DOI: 10.1021/acs.inorgchem.4c00612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Revised: 04/05/2024] [Accepted: 04/08/2024] [Indexed: 04/25/2024]
Abstract
Diverse reactivity of the bulky tris(trimethylsilyl)silyl substituent [Si(SiMe3)3], also known as the hypersilyl group, was observed for amidinate-supported dichloro- and phenylchloroborane complexes. Treatment of the dichloroborane with potassium tris(trimethylsilyl)silyl led to the activation of the backbone β-carbon center and formation of saturated four-membered heterocyclic chloroboranes R'{Si(SiMe3)3}C(NR)2BCl [R' = Ph, R = Cy (3); R' = Ph, R = iPr (6); R' = tBu, R = Cy (8)], whereas the four-membered amidinate hypersilyl-substituted phenyl borane 4 {PhC(NCy)2B(Ph)[Si(SiMe3)3]} was observed for the case of an amidinate-supported phenylchloroborane. The highly deshielded 11B NMR spectroscopic resonance and the distinct difference in the 29Si NMR spectrum confirmed the presence of a σ-donating hypersilyl effect on compounds 3, 6, and 8. Reaction of 3 with the Lewis acid AlCl3 led to the formation of complex 11 in which an unusual cleavage of one of the C-N bonds of the amidinate backbone is observed. Nucleophilic substitution at the boron center of saturated chloroborane 3 with phenyllithium generated the phenylborane derivative 12, whereas the secondary monomeric boron hydride 13 was observed after treatment with alane (AlH3). All compounds (2-13) have been fully characterized by NMR spectroscopy and single-crystal X-ray structure determination studies.
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Affiliation(s)
- Sanjukta Pahar
- Cardiff
Catalysis Institute, School of Chemistry, Cardiff University, Translational Research Hub, Maindy Road, Cathays, Cardiff CF24 4HQ, Cymru/Wales, U.K.
| | - Yara van Ingen
- Cardiff
Catalysis Institute, School of Chemistry, Cardiff University, Translational Research Hub, Maindy Road, Cathays, Cardiff CF24 4HQ, Cymru/Wales, U.K.
| | - Rasool Babaahmadi
- Cardiff
Catalysis Institute, School of Chemistry, Cardiff University, Translational Research Hub, Maindy Road, Cathays, Cardiff CF24 4HQ, Cymru/Wales, U.K.
| | - Benson M. Kariuki
- School
of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, Cymru/Wales, U.K.
| | - Thomas Wirth
- School
of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, Cymru/Wales, U.K.
| | - Emma Richards
- Cardiff
Catalysis Institute, School of Chemistry, Cardiff University, Translational Research Hub, Maindy Road, Cathays, Cardiff CF24 4HQ, Cymru/Wales, U.K.
- School
of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, Cymru/Wales, U.K.
| | - Rebecca L. Melen
- Cardiff
Catalysis Institute, School of Chemistry, Cardiff University, Translational Research Hub, Maindy Road, Cathays, Cardiff CF24 4HQ, Cymru/Wales, U.K.
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2
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Röther A, Farmer JC, Portwich FL, Görls H, Kretschmer R. Anion-Dependent Reactivity of Mono- and Dinuclear Boron Cations. Chemistry 2023; 29:e202302544. [PMID: 37641815 DOI: 10.1002/chem.202302544] [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: 08/04/2023] [Revised: 08/28/2023] [Accepted: 08/28/2023] [Indexed: 08/31/2023]
Abstract
The dinuclear bis(N-heterocyclic carbene) borane adduct 2 rapidly reacts with tritylium salts at room temperature but the outcome is strongly impacted by the respective counter-ion. Using tritylium tetrakis(perfluoro-tert-butoxy)aluminate affords - depending on the solvent - either the bis(boronium) ion 4 or the hydride-bridged dication 5. In case of tritylium hexafluorophosphate, however, H/F exchange occurs between boron and phosphorus yielding the dinuclear BF3 adduct 3 along with phosphorus dihydride trifluoride. H/F exchange also takes place when using the mononuclear N-heterocyclic carbene BH3 adduct 6 and hence provides a facile route to PH2 F3 , which is usually synthesized in more complex reaction sequences regularly involving toxic hydrogen fluoride. DFT calculations shed light on the H/F exchange between the borenium ion and the [PF6 ]- counter-ion and the computed mechanism features only small barriers in line with the experimental observations.
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Affiliation(s)
- Alexander Röther
- Institute of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - James C Farmer
- Institute of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Flavio L Portwich
- Institute of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Helmar Görls
- Institute of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Robert Kretschmer
- Institute of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany
- Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
- Institute of Chemistry, Chemnitz University of Technology, Straße der Nationen 62, 09111, Chemnitz, Germany
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3
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Kaniewska-Laskowska K, Ordyszewska A, Wojnowski T, Halenka H, Czapla M, Chojnacki J, Grubba R. Phosphinoborenium cations stabilized by N-heterocyclic carbenes: synthesis, structure, and reactivity. Dalton Trans 2023; 52:16061-16066. [PMID: 37850531 DOI: 10.1039/d3dt03090c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2023]
Abstract
Phosphinoborenium cations stabilized by N-heterocyclic carbenes (NHCs) were synthesized via the reaction of bromo(phosphino)boranes with NHCs. Their structures were investigated by heteronuclear magnetic resonance spectroscopy, X-ray diffraction, and density functional theory calculations. They possess a planar trigonal boron center directly bonded with the pyramidal phosphanyl group (PR2) and can be treated as cationic phosphinoboranes. The reactivity of the selected NHC-phosphinoborenium cation was tested toward AuCl·SMe2 and Ph2PCl. In both reactions, the titled compound acted as a phosphido group donor under heterolytic cleavage of the P-B bond. Control experiments with parent phosphinoborane emphasized differences between the reactivity of low-coordinate neutral and cationic species with P-B functionality.
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Affiliation(s)
- Kinga Kaniewska-Laskowska
- Department of Inorganic Chemistry, Faculty of Chemistry and Advanced Materials Center, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland.
| | - Anna Ordyszewska
- Department of Inorganic Chemistry, Faculty of Chemistry and Advanced Materials Center, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland.
| | - Tomasz Wojnowski
- Department of Inorganic Chemistry, Faculty of Chemistry and Advanced Materials Center, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland.
| | - Hanna Halenka
- Department of Inorganic Chemistry, Faculty of Chemistry and Advanced Materials Center, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland.
| | - Marcin Czapla
- Laboratory of Quantum Chemistry, Department of Theoretical Chemistry, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Jarosław Chojnacki
- Department of Inorganic Chemistry, Faculty of Chemistry and Advanced Materials Center, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland.
| | - Rafał Grubba
- Department of Inorganic Chemistry, Faculty of Chemistry and Advanced Materials Center, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland.
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4
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Kundu G, Amrutha PR, Raj KV, Tothadi S, Vanka K, Sen SS. Taming the parent oxoborane. Chem Sci 2023; 14:5894-5898. [PMID: 37293651 PMCID: PMC10246693 DOI: 10.1039/d3sc01544k] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 04/25/2023] [Indexed: 06/10/2023] Open
Abstract
Despite recent advancements in the chemistry of multiply bound boron compounds, the laboratory isolation of the parent oxoborane moiety, HBO has long remained an unsolved and well-recognized challenge. The reaction of 6-SIDipp·BH3 [6-SIDipp = 1,3-di(2,6-diisopropylphenyl)tetrahydropyrimidine-2-ylidene] with GaCl3 afforded an unusual boron-gallium 3c-2e compound (1). The addition of water to 1 resulted in the release of H2 and the formation of a rare acid stabilized neutral parent oxoborane, LB(H)[double bond, length as m-dash]O (2). Crystallographic and density functional theory (DFT) analyses support the presence of a terminal B[double bond, length as m-dash]O double bond. Subsequent addition of another equivalent of water molecule led to hydrolysis of the B-H bond to the B-OH bond, but the 'B[double bond, length as m-dash]O' moiety remained intact, resulting in the formation of the hydroxy oxoborane compound (3), which can be classified as a monomeric form of metaboric acid.
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Affiliation(s)
- Gargi Kundu
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory Dr Homi Bhabha Road, Pashan Pune 411008 India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad 201002 India
| | - P R Amrutha
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory Dr Homi Bhabha Road, Pashan Pune 411008 India
| | - K Vipin Raj
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad 201002 India
- Physical and Material Chemistry Division, CSIR-National Chemical Laboratory Dr Homi Bhabha Road, Pashan Pune 411008 India
| | - Srinu Tothadi
- Analytical and Environmental Sciences Division and Centralized Instrumentation Facility, CSIR-Central Salt and Marine Chemicals Research Institute Gijubhai Badheka Marg Bhavnagar-364002 India
| | - Kumar Vanka
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad 201002 India
- Physical and Material Chemistry Division, CSIR-National Chemical Laboratory Dr Homi Bhabha Road, Pashan Pune 411008 India
| | - Sakya S Sen
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory Dr Homi Bhabha Road, Pashan Pune 411008 India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad 201002 India
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5
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Kundu G, Ajithkumar VS, Raj KV, Vanka K, Tothadi S, Sen SS. Substitution at sp 3 boron of a six-membered NHC·BH 3: convenient access to a dihydroxyborenium cation. Chem Commun (Camb) 2022; 58:3783-3786. [PMID: 35229841 DOI: 10.1039/d1cc06816d] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we have undertaken the synthesis and investigated the reactivity of a 6-membered saturated NHC borane adduct (1). Direct electrophilic halogenation of 1 with a stoichiometric amount of I2 led to NHC boryl iodides, 6-SIDipp·BH2I (2) and 6-SIDipp·BHI2 (3), which were further reacted with various nucleophiles to give novel 6-SIDipp based mono and disubstituted boranes with OTf (4 and 6) or ONO2 (5 and 7) functional groups. The addition of Br2/H2O to 1 smoothly results in a dihydroxyborenium cation (8).
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Affiliation(s)
- Gargi Kundu
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune 411008, India. .,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - V S Ajithkumar
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune 411008, India. .,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - K Vipin Raj
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India.,Physical and Material Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Kumar Vanka
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India.,Physical and Material Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Srinu Tothadi
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India.,Analytical and Environmental Sciences Division and Centralized Instrumentation Facility, CSIR-Central Salt and Marine Chemicals Research Institute, Gijubhai Badheka Marg, Bhavnagar-364002, India
| | - Sakya S Sen
- Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune 411008, India. .,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
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6
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Gao H, Müller R, Irran E, Klare HFT, Kaupp M, Oestreich M. Competition for Hydride between Silicon and Boron: Synthesis and Characterization of a Hydroborane-Stabilized Silylium Ion. Chemistry 2021; 28:e202104464. [PMID: 34918852 PMCID: PMC9303568 DOI: 10.1002/chem.202104464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Indexed: 11/16/2022]
Abstract
Potent main‐group Lewis acids are capable of activating element‐hydrogen bonds. To probe the rivalry for hydride between silylium‐ and borenium‐ion centers, a neutral precursor with the hydrosilane and hydroborane units in close proximity on a naphthalene‐1,8‐diyl platform was designed. Abstraction of one hydride leads to a hydroborane‐stabilized silylium ion rather than a hydrosilane‐coordinated borenium ion paired with [B(C6F5)4]− or [HCB11Cl11]− as counteranions. Characterization by multinuclear NMR spectroscopy and X‐ray diffraction supported by DFT calculations reveals a cationic, unsymmetrical open three‐center, two‐electron (3c2e) Si−H−B linkage.
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Affiliation(s)
- Haopeng Gao
- Technische Universität Berlin: Technische Universitat Berlin, Chemistry, GERMANY
| | - Robert Müller
- Technische Universität Berlin: Technische Universitat Berlin, Chemistry, GERMANY
| | - Elisabeth Irran
- Technische Universität Berlin: Technische Universitat Berlin, Chemistry, GERMANY
| | - Hendrik F T Klare
- Technische Universität Berlin: Technische Universitat Berlin, Chemistry, GERMANY
| | - Martin Kaupp
- Technische Universität Berlin: Technische Universitat Berlin, Chemistry, GERMANY
| | - Martin Oestreich
- Technische Universität Berlin: Technische Universitat Berlin, Chemistry, Straße des 17. Juni 115, 10623, Berlin, GERMANY
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7
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Deis T, Medici F, Poussard-Schulz A, Lemière G, Fensterbank L. Synthesis and reactivity of an anionic NHC-borane featuring a weakly coordinating silicate anion. J Organomet Chem 2021. [DOI: 10.1016/j.jorganchem.2021.122120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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8
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Shih DN, Boobalan R, Liu YH, Chein RJ, Chiu CW. [B-Cl-B] + Cations: Chloroborane Masked Chiral Borenium Ions. Inorg Chem 2021; 60:16266-16272. [PMID: 34672549 DOI: 10.1021/acs.inorgchem.1c02073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A tricoordinate borenium ion has received considerable attention in recent years for its applications in Lewis acid catalysis. Over the years, asymmetric catalysis mediated by a chiral borenium ion has also been developed. To stabilize the electron-deficient boron atom, a series of chloroborane masked borenium ions featuring the symmetrical [B-Cl-B]+ linkage are prepared and utilized as the catalyst for the enantioselective Diels-Alder cycloaddition of cyclopentadiene and 2,2,2-trifluoroethyl acrylate. The presence of a Cp* ligand is critical in realizing the cyclic diboron compounds, and the stability of the resulting [B-Cl-B]+ cation is dependent on the steric bulkiness of the oxazolidinone moiety. The stereoselectivity of the Diels-Alder cycloaddition is controlled by the substituents of the chiral oxazolidinone ligand and could be further improved via the coordination of SnCl4 at the bridging chloride of the [B-Cl-B]+ cation.
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Affiliation(s)
- Ding-Nan Shih
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | | | - Yi-Hung Liu
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Rong-Jie Chein
- Institute of Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Ching-Wen Chiu
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
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9
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Singh T, Sahoo SC, Bharatam PV. Compound with possible N → N coordination bond: Synthesis, crystal structure and electronic structure analysis. Tetrahedron Lett 2021. [DOI: 10.1016/j.tetlet.2021.153246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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10
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Wang Q, Meng W, Feng X, Du H. B(
C
6
F
5
)
3
‐Catalyzed
Hydroboration of Alkenes with
N
‐Heterocyclic
Carbene Boranes
via
B—H Bond Activation. CHINESE J CHEM 2021. [DOI: 10.1002/cjoc.202000489] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Qiaotian Wang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences Beijing 100190, China University of Chinese Academy of Sciences Beijing 100049 China
| | - Wei Meng
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences Beijing 100190, China University of Chinese Academy of Sciences Beijing 100049 China
| | - Xiangqing Feng
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences Beijing 100190, China University of Chinese Academy of Sciences Beijing 100049 China
| | - Haifeng Du
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences Beijing 100190, China University of Chinese Academy of Sciences Beijing 100049 China
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11
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Maar RR, Katzman BD, Boyle PD, Staroverov VN, Gilroy JB. Cationic Boron Formazanate Dyes**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202015036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Ryan R. Maar
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario 1151 Richmond Street North London Ontario N6A 5B7 Canada
| | - Benjamin D. Katzman
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario 1151 Richmond Street North London Ontario N6A 5B7 Canada
| | - Paul D. Boyle
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario 1151 Richmond Street North London Ontario N6A 5B7 Canada
| | - Viktor N. Staroverov
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario 1151 Richmond Street North London Ontario N6A 5B7 Canada
| | - Joe B. Gilroy
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario 1151 Richmond Street North London Ontario N6A 5B7 Canada
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12
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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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13
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Maar RR, Katzman BD, Boyle PD, Staroverov VN, Gilroy JB. Cationic Boron Formazanate Dyes*. Angew Chem Int Ed Engl 2021; 60:5152-5156. [PMID: 33217138 DOI: 10.1002/anie.202015036] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Indexed: 12/12/2022]
Abstract
Incorporation of cationic boron atoms into molecular frameworks is an established strategy for creating chemical species with unusual bonding and reactivity but is rarely thought of as a way of enhancing molecular optoelectronic properties. Using boron formazanate dyes as examples, we demonstrate that the wavelengths, intensities, and type of the first electronic transitions in BN heterocycles can be modulated by varying the charge, coordination number, and supporting ligands at the cationic boron atom. UV-vis absorption spectroscopy measurements and density-functional (DFT) calculations show that these modulations are caused by changes in the geometry and extent of π-conjugation of the boron formazanate ring. These findings suggest a new strategy for designing optoelectronic materials based on π-conjugated heterocycles containing boron and other main-group elements.
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Affiliation(s)
- Ryan R Maar
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, 1151 Richmond Street North, London, Ontario, N6A 5B7, Canada
| | - Benjamin D Katzman
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, 1151 Richmond Street North, London, Ontario, N6A 5B7, Canada
| | - Paul D Boyle
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, 1151 Richmond Street North, London, Ontario, N6A 5B7, Canada
| | - Viktor N Staroverov
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, 1151 Richmond Street North, London, Ontario, N6A 5B7, Canada
| | - Joe B Gilroy
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, 1151 Richmond Street North, London, Ontario, N6A 5B7, Canada
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14
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Chen C, Li J, Daniliuc CG, Mück‐Lichtenfeld C, Kehr G, Erker G. The [(NHC)B(H)C
6
F
5
]
+
Cations and Their [B](H)−CO Borane Carbonyls. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009353] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Chaohuang Chen
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Jun Li
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Constantin G. Daniliuc
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Christian Mück‐Lichtenfeld
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
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15
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Chen C, Li J, Daniliuc CG, Mück-Lichtenfeld C, Kehr G, Erker G. The [(NHC)B(H)C 6 F 5 ] + Cations and Their [B](H)-CO Borane Carbonyls. Angew Chem Int Ed Engl 2020; 59:21460-21464. [PMID: 32705756 DOI: 10.1002/anie.202009353] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 11/11/2022]
Abstract
Hydride abstraction from the heterocyclic carbene borane adducts (NHC)BH2 C6 F5 (NHC: IMes or IMe4 ) gave the B-H containing [(NHC)B(H)C6 F5 ]+ borenium cations. They added carbon monoxide to give the respective [(NHC)B(H)(C6 F5 )CO]+ boron carbonyl cations. Carbon nucleophiles add to the boron carbonyl to give [B](H) acyls. Hydride reduced the [B]CO cation to hydroxymethylborane derivatives.
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Affiliation(s)
- Chaohuang Chen
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Jun Li
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Christian Mück-Lichtenfeld
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
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16
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Chen C, Daniliuc CG, Mück-Lichtenfeld C, Kehr G, Erker G. A BH Borenium-Derived Thioxoborane, Its Persulfide, and Their Li +-Induced Reactions with Alkynes and with Carbon Dioxide. J Am Chem Soc 2020; 142:19763-19771. [PMID: 33166151 DOI: 10.1021/jacs.0c10078] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Insertion of sulfur into the B-H bond of the BH borenium salt [IMes(C6F5)BH]+ followed by deprotonation gave the thioxoborane IMes(C6F5)B═S. Subsequent treatment with additional sulfur gave the corresponding boron persulfide, a NHC-stabilized boradithiirane. The B═S compound reacted with carbon dioxide in the presence of the lithium salt Li[B(C6F5)4] by formal [2+2] cycloaddition to give a boron thiocarbonate-type product. The boron persulfide formally inserted phenyl acetylene into the B-S bond in the presence of Li[B(C6F5)4] to give the respective five-membered heterocycle.
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Affiliation(s)
- Chaohuang Chen
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Christian Mück-Lichtenfeld
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
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17
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Khoo S, Siu CK, So CW. A Base-Stabilized Silylene-Promoted C(sp3)–H Borylation and H2 Activation. Inorg Chem 2020; 59:9551-9559. [DOI: 10.1021/acs.inorgchem.0c00426] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sabrina Khoo
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Chi-Kit Siu
- Department of Chemistry, City University of Hong Kong, Hong Kong SAR, China
| | - Cheuk-Wai So
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
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18
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Lam J, Cao LL, Farrell JM, Stephan DW. Reactions of carbene-stabilized borenium cations. Dalton Trans 2020; 49:1839-1846. [PMID: 31965118 DOI: 10.1039/c9dt04731j] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper we probe the reactivity of the borenium cations [C3H2(NCH2C6H4)(NCH2Ph)BH][B(C6F5)4] 2 and [C3H2(NCH2C6H4)2B][B(C6F5)4] 3. The reactions of 2 with cyclohexene or 3,3-dimethyl-1-butene gave the alkyl-aryl borenium salts [PhCH2(CHN)2CCH2C6H4BR][B(C6F5)4] (R = Cy 4, CH2CH2tBu 5) while the corresponding reactions with diphenylacetylene, 1-hexyne and 1-phenyl-1-propyne gave the aryl-alkenyl borenium cation salts [PhCH2(CHN)2CCH2C6H4BC(R1)C(H)R2][B(C6F5)4] (R1 = R2 = Ph 6, R1 = H, R2 = C4H97, R1 = Me, R2 = Ph 8a, R1 = Ph, R2 = Me 8b). In contrast, the reaction of 2 with ethynyldiphenylphosphane or 2-vinylpyridine lead to the formation of the adducts, [PhCH2(CHN)2CCH2C6H4B(H)P(Ph2)CCH][B(C6F5)4] 9, [PhCH2(CHN)2CCH2C6H4B(H)NC5H4C(H)CH2][B(C6F5)4] 10, respectively, while the more bulky donor H2C[double bond, length as m-dash]C(Ph)PMes2 gave 1,2-hydroboration of the phosphinoalkene affording [PhCH2(CHN)2CCH2C6H4BCH2CH(Ph)PMes2][B(C6F5)4] 11. In another vein of reactivity, one or two equivalents of the FLP, PtBu3/B(C6F5)3 is shown to react with 3 to give the zwitterionic borenium-borate species [C2H2(NCH(BC(CHNCH2C6H4)2)C6H4)(NCH(B(C6F5)3)C6H4)CB] 12 and the anionic bis-borate species[tBu3PH][C2H2(NCH(B(C6F5)3)2C6H4)2CB] 13. The implications of these findings are discussed.
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Affiliation(s)
- Jolie Lam
- Department of Chemistry, University of Toronto, M5S3H6, Canada.
| | - Levy L Cao
- Department of Chemistry, University of Toronto, M5S3H6, Canada.
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19
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Brückner T, Stennett TE, Heß M, Braunschweig H. Single and Double Hydroboration of B-B Triple Bonds and Convergent Routes to a Cationic Tetraborane. J Am Chem Soc 2019; 141:14898-14903. [PMID: 31454483 DOI: 10.1021/jacs.9b07991] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A compound with a boron-boron triple bond is shown to undergo stepwise hydroboration reactions with catecholborane to yield an unsymmetrical hydro(boryl)diborene and a 2,3-dihydrotetraborane. Abstraction of H- from the latter compound produces an unusual cationic, planar tetraborane with a hydrogen atom bridging the central B2 moiety. Spectroscopic and crystallographic data and DFT calculations support a "protonated diborene" structure for this compound, which can also be accessed via direct protonation of the corresponding diborene.
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20
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Yang W, Krantz KE, Freeman LA, Dickie DA, Molino A, Kaur A, Wilson DJD, Gilliard RJ. Stable Borepinium and Borafluorenium Heterocycles: A Reversible Thermochromic "Switch" Based on Boron-Oxygen Interactions. Chemistry 2019; 25:12512-12516. [PMID: 31334883 DOI: 10.1002/chem.201903348] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Indexed: 12/13/2022]
Abstract
The first examples of N-heterocyclic carbene (NHC) and cyclic(alkyl)(amino) carbene (CAAC) stabilized borepinium and borafluorenium heterocycles are reported herein. The optical properties of the heterocyclic borenium cations were tuned by varying the Lewis base and by changing the number of atoms in the ring. More importantly, functionalizing the cationic boron ring system in the NHC-borafluorenium cation affords a temperature-sensitive molecule with reversible colorimetric "turn off/turn on" properties in solution. Notably, this is the first report of thermochromism in these cationic species. This property, which is mediated by an intermolecular boron-oxygen bond equilibrium, was examined in detail by X-ray crystallography, variable temperature-UV/Vis absorption spectroscopy (VT-UV/Vis), and density functional theory (DFT).
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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
| | - Aishvaryadeep Kaur
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Victoria, Australia
| | - 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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21
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Dübek G, Franz D, Eisenhut C, Altmann PJ, Inoue S. Reactivity of an NHC-stabilized pyramidal hydrosilylene with electrophilic boron sources. Dalton Trans 2019; 48:5756-5765. [DOI: 10.1039/c9dt00608g] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An NHC-stabilized three-coordinate hydrosilylene dehydrogenates ammonia borane and forms more stable complexes with BH3, BPh3, BBr3 and BPhBr2 but less stable ones with BF3, and BCl3 for which ligand scrambling occurs.
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Affiliation(s)
- Gizem Dübek
- Department of Chemistry
- WACKER-Institute of Silicon Chemistry and Catalysis Research Centre
- Technische Universität München
- 85748 Garching bei München
- Germany
| | - Daniel Franz
- Department of Chemistry
- WACKER-Institute of Silicon Chemistry and Catalysis Research Centre
- Technische Universität München
- 85748 Garching bei München
- Germany
| | - Carsten Eisenhut
- Institut für Chemie
- Technische Universität Berlin
- 10623 Berlin
- Germany
| | - Philipp J. Altmann
- Department of Chemistry
- WACKER-Institute of Silicon Chemistry and Catalysis Research Centre
- Technische Universität München
- 85748 Garching bei München
- Germany
| | - Shigeyoshi Inoue
- Department of Chemistry
- WACKER-Institute of Silicon Chemistry and Catalysis Research Centre
- Technische Universität München
- 85748 Garching bei München
- Germany
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22
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Franz D, Inoue S. Cationic Complexes of Boron and Aluminum: An Early 21st Century Viewpoint. Chemistry 2018; 25:2898-2926. [PMID: 30113744 DOI: 10.1002/chem.201803370] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Indexed: 01/03/2023]
Abstract
Boron and aluminum are lighter Group 13 elements, found in daily life commodities, and considered environmentally benign. Nevertheless, they markedly differ in their elemental properties (e.g., metal character, atomic radius). The use of Lewis acidic complexes of boron and aluminum for methods of bond activation and catalysis (e.g., hydrogenation of unsaturated substrates, polymerization of olefins and epoxides) is quickly expanding. The introduction of cationic charge may boost the metalloid-centered Lewis acidity and allow for its fine-tuning particularly with regard to preference for "hard" or "soft" Lewis bases (i.e., substrates). Especially the isolation of low-coordinate cations (number of ligand atoms smaller than four) demands elaborate techniques of thermodynamic and kinetic stabilization (i.e., electronic saturation and steric shielding) by a ligand system. Furthermore, the properties of the solvent and the counteranion must be considered with care. Here, selected examples of boron and aluminum cations are described.
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Affiliation(s)
- Daniel Franz
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstr. 4, 85748, Garching bei München, Germany
| | - Shigeyoshi Inoue
- Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstr. 4, 85748, Garching bei München, Germany
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23
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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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24
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Li L, Lei M, Xie Y, Weinhold F, Schaefer HF. Quantitative Theoretical Predictions and Qualitative Bonding Analysis of the Divinylborinium System and Its Al, Ga, In, and Tl Congeners. Inorg Chem 2018; 57:7851-7859. [PMID: 29911861 DOI: 10.1021/acs.inorgchem.8b00968] [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
A substituted divinylborinium cation was synthesized recently and characterized crystallographically as a gauche structure with a 153° C1-C2-C3-C4 dihedral angle. A full theoretical geometrical optimization of the bis(2-mesityl-1,2-diphenylvinyl)-borane cation shows excellent agreement with the crystal structure. However, for the parent unsubstituted divinylborinium cation, we predict a nearly 90° C1-C2-C3-C4 dihedral angle using the CCSD(T)/cc-pVTZ coupled cluster method. The cis and trans planar geometries (0° and 180° for the C1-C2-C3-C4 dihedral angle) proved to be transition states with energy barriers of 2.8 and 2.3 kcal/mol, respectively, with respect to unimolecular conversion to the gauche equilibrium. The structures of the heavier boron group cations (Al, Ga, In, and Tl) have also been investigated here, finding even lower energy barriers (0.3-0.7 kcal/mol). After the ZPVE corrections, the barriers are further decreased. The torsional angles for the unknown Al, Ga, In, and Tl dimesityl substituted compounds should be somewhat less than 153°. Many of these findings may be understood in terms of qualitative electronic structure theory. The torsional folding of borane complex, including cationic divinylborinium and elementary vinylborane (C2H3BH2) or chlorovinylborane (C2H3BHCl) precursors, are investigated with natural bond orbital (NBO) analysis to unveil the electronic origins of the torsional properties. The NBO-based descriptors are employed to systematically deconstruct complex torsional dependence into a balanced portrayal of hyperconjugative and steric effects.
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Affiliation(s)
- Longfei Li
- State Key Laboratory of Chemical Resource Engineering, Institute of Materia Medica, College of Science , Beijing University of Chemical Technology , Beijing 100029 , P.R. China.,Center for Computational Quantum Chemistry , University of Georgia , Athens , Georgia 30602 , United States
| | - Ming Lei
- State Key Laboratory of Chemical Resource Engineering, Institute of Materia Medica, College of Science , Beijing University of Chemical Technology , Beijing 100029 , P.R. China
| | - Yaoming Xie
- Center for Computational Quantum Chemistry , University of Georgia , Athens , Georgia 30602 , United States
| | - Frank Weinhold
- Department of Chemistry , University of Wisconsin , Madison , Wisconsin 53706 , United States
| | - Henry F Schaefer
- Center for Computational Quantum Chemistry , University of Georgia , Athens , Georgia 30602 , United States
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25
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Franz D, Szilvási T, Pöthig A, Deiser F, Inoue S. Three-Coordinate Boron(III) and Diboron(II) Dications. Chemistry 2018; 24:4283-4288. [DOI: 10.1002/chem.201800609] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Daniel Franz
- Department of Chemistry, Catalysis Research Center; Institute of Silicon Chemistry; Technische Universität München; Lichtenbergstr. 4 85748 Garching bei München Germany
| | - Tibor Szilvási
- Department of Chemical and Biological Engineering; University of Wisconsin-Madison; 1415 Engineering Drive Madison WI 53706-1607 USA
| | - Alexander Pöthig
- Department of Chemistry, Catalysis Research Center; Institute of Silicon Chemistry; Technische Universität München; Lichtenbergstr. 4 85748 Garching bei München Germany
| | - Franziska Deiser
- Department of Chemistry, Catalysis Research Center; Institute of Silicon Chemistry; Technische Universität München; Lichtenbergstr. 4 85748 Garching bei München Germany
| | - Shigeyoshi Inoue
- Department of Chemistry, Catalysis Research Center; Institute of Silicon Chemistry; Technische Universität München; Lichtenbergstr. 4 85748 Garching bei München Germany
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26
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Zheng J, Li ZH, Wang H. Addition of dihydrogen to a borylborenium center. Chem Sci 2018; 9:1433-1438. [PMID: 29675190 PMCID: PMC5883945 DOI: 10.1039/c7sc04987k] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 11/27/2017] [Indexed: 11/21/2022] Open
Abstract
The activation of a H-H bond, the simplest covalent bond, is a fundamentally important process. Addition of H2 to an elemental center typically occurs on low valent transition metal or main group complexes through oxidative addition to afford metal dihydride complexes. In contrast, activation of H2 on a high valent center generally results in heterolytic cleavage of the H-H bond to a proton and hydride. Here, we report experimental and computational evidence for the addition of H2 to a borenium center in an N-heterocyclic carbene (NHC) coordinated borylborenium cation, which leads to the formation of a dihydroborenium complex accompanied by the elimination of two σ-bonded substituents, namely mesityl (Mes) and pinacolboryl (Bpin) groups, as mesitylboronic ester.
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Affiliation(s)
- Junhao Zheng
- Department of Chemistry , Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials , Fudan University , Handan Road 220 , Shanghai , 200433 , China . ;
| | - Zhen Hua Li
- Department of Chemistry , Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials , Fudan University , Handan Road 220 , Shanghai , 200433 , China . ;
| | - Huadong Wang
- Department of Chemistry , Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials , Fudan University , Handan Road 220 , Shanghai , 200433 , China . ;
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27
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Hui Z, Watanabe T, Tobita H. Synthesis of Base-Stabilized Hydrido(hydroborylene)tungsten Complexes and Their Reactions with Terminal Alkynes To Give η3-Boraallyl Complexes. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00723] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zeping Hui
- Department of Chemistry,
Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Takahito Watanabe
- Department of Chemistry,
Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
| | - Hiromi Tobita
- Department of Chemistry,
Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
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28
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Farrell JM, Schmidt D, Grande V, Würthner F. Synthesis of a Doubly Boron-Doped Perylene through NHC-Borenium Hydroboration/C−H Borylation/Dehydrogenation. Angew Chem Int Ed Engl 2017; 56:11846-11850. [DOI: 10.1002/anie.201706346] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Jeffrey M. Farrell
- Institut für Organische Chemie; Universität Würzburg; Am Hubland 97074 Würzburg Germany
| | - David Schmidt
- Center for Nanosystems Chemistry (CNC); Universität Würzburg; Theodor-Boveri-Weg 97074 Würzburg Germany
| | - Vincenzo Grande
- Center for Nanosystems Chemistry (CNC); Universität Würzburg; Theodor-Boveri-Weg 97074 Würzburg Germany
| | - Frank Würthner
- Institut für Organische Chemie; Universität Würzburg; Am Hubland 97074 Würzburg Germany
- Center for Nanosystems Chemistry (CNC); Universität Würzburg; Theodor-Boveri-Weg 97074 Würzburg Germany
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29
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Farrell JM, Schmidt D, Grande V, Würthner F. Synthesis of a Doubly Boron-Doped Perylene through NHC-Borenium Hydroboration/C−H Borylation/Dehydrogenation. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201706346] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jeffrey M. Farrell
- Institut für Organische Chemie; Universität Würzburg; Am Hubland 97074 Würzburg Germany
| | - David Schmidt
- Center for Nanosystems Chemistry (CNC); Universität Würzburg; Theodor-Boveri-Weg 97074 Würzburg Germany
| | - Vincenzo Grande
- Center for Nanosystems Chemistry (CNC); Universität Würzburg; Theodor-Boveri-Weg 97074 Würzburg Germany
| | - Frank Würthner
- Institut für Organische Chemie; Universität Würzburg; Am Hubland 97074 Würzburg Germany
- Center for Nanosystems Chemistry (CNC); Universität Würzburg; Theodor-Boveri-Weg 97074 Würzburg Germany
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30
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Affiliation(s)
- Ya-Fan Lin
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, No. 100, Shih-Chuan First Road, Kaohsiung, Taiwan 80708
| | - Ching-Wen Chiu
- Department of Chemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei, Taiwan 10617
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31
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McGough JS, Cid J, Ingleson MJ. Catalytic Electrophilic C−H Borylation Using NHC⋅Boranes and Iodine Forms C2-, not C3-, Borylated Indoles. Chemistry 2017; 23:8180-8184. [DOI: 10.1002/chem.201702060] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Indexed: 11/11/2022]
Affiliation(s)
- John S. McGough
- School of Chemistry; University of Manchester; Oxford Road Manchester M13 9PL UK
| | - Jessica Cid
- School of Chemistry; University of Manchester; Oxford Road Manchester M13 9PL UK
| | - Michael J. Ingleson
- School of Chemistry; University of Manchester; Oxford Road Manchester M13 9PL UK
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32
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Scherpf T, Feichtner K, Gessner VH. Using Ylide Functionalization to Stabilize Boron Cations. Angew Chem Int Ed Engl 2017; 56:3275-3279. [PMID: 28185370 PMCID: PMC5363341 DOI: 10.1002/anie.201611677] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/26/2017] [Indexed: 11/17/2022]
Abstract
The metalated ylide YNa [Y=(Ph3 PCSO2 Tol)- ] was employed as X,L-donor ligand for the preparation of a series of boron cations. Treatment of the bis-ylide functionalized borane Y2 BH with different trityl salts or B(C6 F5 )3 for hydride abstraction readily results in the formation of the bis-ylide functionalized boron cation [Y-B-Y]+ (2). The high donor capacity of the ylide ligands allowed the isolation of the cationic species and its characterization in solution as well as in solid state. DFT calculations demonstrate that the cation is efficiently stabilized through electrostatic effects as well as π-donation from the ylide ligands, which results in its high stability. Despite the high stability of 2 [Y-B-Y]+ serves as viable source for the preparation of further borenium cations of type Y2 B+ ←LB by addition of Lewis bases such as amines and amides. Primary and secondary amines react to tris(amino)boranes via N-H activation across the B-C bond.
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Affiliation(s)
- Thorsten Scherpf
- Chair of Inorganic Chemistry IIFaculty of Chemistry and BiochemistryRuhr University BochumUniversitätsstraße 15044780BochumGermany
| | - Kai‐Stephan Feichtner
- Chair of Inorganic Chemistry IIFaculty of Chemistry and BiochemistryRuhr University BochumUniversitätsstraße 15044780BochumGermany
| | - Viktoria H. Gessner
- Chair of Inorganic Chemistry IIFaculty of Chemistry and BiochemistryRuhr University BochumUniversitätsstraße 15044780BochumGermany
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33
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Scherpf T, Feichtner KS, Gessner VH. Using Ylide Functionalization to Stabilize Boron Cations. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611677] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Thorsten Scherpf
- Chair of Inorganic Chemistry II; Faculty of Chemistry and Biochemistry; Ruhr University Bochum; Universitätsstraße 150 44780 Bochum Germany
| | - Kai-Stephan Feichtner
- Chair of Inorganic Chemistry II; Faculty of Chemistry and Biochemistry; Ruhr University Bochum; Universitätsstraße 150 44780 Bochum Germany
| | - Viktoria H. Gessner
- Chair of Inorganic Chemistry II; Faculty of Chemistry and Biochemistry; Ruhr University Bochum; Universitätsstraße 150 44780 Bochum Germany
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34
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Kong L, Lu W, Yongxin L, Ganguly R, Kinjo R. Formation of Boron–Main-Group Element Bonds by Reactions with a Tricoordinate Organoboron L2PhB: (L = Oxazol-2-ylidene). Inorg Chem 2017; 56:5586-5593. [DOI: 10.1021/acs.inorgchem.6b02993] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lingbing Kong
- Division
of Chemistry and Biological Chemistry, School of Physical
and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University, Singapore 637371, Singapore
| | - Wei Lu
- Division
of Chemistry and Biological Chemistry, School of Physical
and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University, Singapore 637371, Singapore
| | - Li Yongxin
- Division
of Chemistry and Biological Chemistry, School of Physical
and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University, Singapore 637371, Singapore
| | - Rakesh Ganguly
- Division
of Chemistry and Biological Chemistry, School of Physical
and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University, Singapore 637371, Singapore
| | - Rei Kinjo
- Division
of Chemistry and Biological Chemistry, School of Physical
and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University, Singapore 637371, Singapore
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35
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Kong L, Lu W, Li Y, Ganguly R, Kinjo R. Isolation of a Diborane(6) Dication: Formation and Cleavage of an Electron-Precise B(sp3)–B(sp3) Bond. J Am Chem Soc 2016; 138:8623-9. [DOI: 10.1021/jacs.6b04858] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lingbing Kong
- Division
of Chemistry and Biological Chemistry, School of Physical
and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University, 637371, Singapore
| | - Wei Lu
- Division
of Chemistry and Biological Chemistry, School of Physical
and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University, 637371, Singapore
| | - Yongxin Li
- Division
of Chemistry and Biological Chemistry, School of Physical
and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University, 637371, Singapore
| | - Rakesh Ganguly
- Division
of Chemistry and Biological Chemistry, School of Physical
and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University, 637371, Singapore
| | - Rei Kinjo
- Division
of Chemistry and Biological Chemistry, School of Physical
and Mathematical Sciences, and ‡NTU-CBC Crystallography Facility, Nanyang Technological University, 637371, Singapore
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36
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McGough JS, Butler SM, Cade IA, Ingleson MJ. Highly selective catalytic trans-hydroboration of alkynes mediated by borenium cations and B(C 6F 5) 3. Chem Sci 2016; 7:3384-3389. [PMID: 29997833 PMCID: PMC6006955 DOI: 10.1039/c5sc04798f] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 02/12/2016] [Indexed: 11/27/2022] Open
Abstract
The trans-hydroboration of terminal alkynes mediated by borenium cations [NHC(9-BBN)]+ (NHC = N-heterocyclic carbene, 9-BBN = 9-borabicyclo(3.3.1)nonane) exclusively affords Z-vinylboranes. NHCs and chelating dialkyl substituents on the borenium cation and "non"-basic anions were essential to preclude alternative reactions including dehydroboration. Deuterium labelling studies indicate the mechanism involves addition of the boron electrophile to the alkyne and transfer of hydride to the opposite face of the activated alkyne. trans-Hydroboration proceeds with only catalytic amounts of B(C6F5)3 or [Ph3C][B(C6F5)4] to activate the (NHC)9-BBN(H) precursor with the borenium regenerated in the hydride transfer step. The NHC can be removed from the trans-hydroborated products by the addition of Et2O-BF3 providing access to vinylBBN species effective for Suzuki-Miyaura couplings to generate Z-alkenes. Combinations of catalytic B(C6F5)3 and stoichiometric [HB(C6F5)3]- also lead to trans-hydroboration of terminal alkynes to form Z-isomers of [arylCH[double bond, length as m-dash]CHB(C6F5)3]-.
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Affiliation(s)
- John S McGough
- University of Manchester , Oxford Road , Manchester M13 9PL. , UK .
| | - Samuel M Butler
- University of Manchester , Oxford Road , Manchester M13 9PL. , UK .
| | - Ian A Cade
- University of Manchester , Oxford Road , Manchester M13 9PL. , UK .
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37
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Devillard M, Mallet-Ladeira S, Bouhadir G, Bourissou D. Diverse reactivity of borenium cations with >N–H compounds. Chem Commun (Camb) 2016; 52:8877-80. [DOI: 10.1039/c6cc03183h] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The P-stabilized borenium 1 displays rich reactivity towards >N–H compounds: substitution reaction at a borenium center with Ph2NH, Lewis adduct formation and subsequent deprotonation with NH3, B–Mes cleavage and formation of a dicationic species with HNTf2.
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Affiliation(s)
| | - Sonia Mallet-Ladeira
- Université Paul Sabatier
- Institut de Chimie de Toulouse (FR 2599)
- 31062 Toulouse cedex 9
- France
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38
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Ghadwal RS. Carbon-based two electron σ-donor ligands beyond classical N-heterocyclic carbenes. Dalton Trans 2016; 45:16081-16095. [DOI: 10.1039/c6dt02158a] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Recent advances in N-heterocyclic carbene-derived carbon-based two electron σ-donor ligands are presented in this perspective.
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Affiliation(s)
- Rajendra S. Ghadwal
- Molecular Inorganic Chemistry and Catalysis
- Anorganische Chemie & Strukturchemie
- Fakultät für Chemie
- Universität Bielefeld
- Bielefeld
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39
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Lee WH, Lin YF, Lee GH, Peng SM, Chiu CW. N-Heterocyclic olefin stabilized boron dication. Dalton Trans 2016; 45:5937-40. [DOI: 10.1039/c5dt03847b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Boron mono- and di-cations featuring a nucleophilic N-heterocyclic olefin and the pentamethylcyclopentadienyl substituent have been prepared and structurally characterized. Experimental and theoretical investigations show that [η5-Cp*B-NHO]2+is considerably more Lewis acidic than [η5-Cp*B-IMes]2+due to the steric congestion imposed by the bent geometry of NHO around the central boron atom.
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Affiliation(s)
- Wan-Hua Lee
- Department of Chemistry
- National Taiwan University
- Taipei
- Taiwan
| | - Ya-Fan Lin
- Department of Chemistry
- National Taiwan University
- Taipei
- Taiwan
| | - Gene-Hsiang Lee
- Department of Chemistry
- National Taiwan University
- Taipei
- Taiwan
| | - Shie-Ming Peng
- Department of Chemistry
- National Taiwan University
- Taipei
- Taiwan
| | - Ching-Wen Chiu
- Department of Chemistry
- National Taiwan University
- Taipei
- Taiwan
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40
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Prokofjevs A. Thermal Dehydrogenation of Base-Stabilized B2H5(+) Complexes and Its Role in C-H Borylation. Angew Chem Int Ed Engl 2015; 54:13401-5. [PMID: 26377358 PMCID: PMC4704089 DOI: 10.1002/anie.201507647] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Indexed: 12/20/2022]
Abstract
Thermally induced dehydrogenation of the H-bridged cation L2B2H5(+) (L=Lewis base) is proposed to be the key step in the intramolecular C-H borylation of tertiary amine boranes activated with catalytic amounts of strong "hydridophiles". Loss of H2 from L2B2H5(+) generates the highly reactive cation L2B2H3(+), which in its sp(2)-sp(3) diborane(4) form then undergoes either an intramolecular C-H insertion with B-B bond cleavage, or captures BH3 to produce L2B3H6(+). The effect of the counterion stability on the outcome of the reaction is illustrated by formation of LBH2C6F5 complexes through disproportionation of L2B2H5(+) HB(C6F5)3(-) .
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Affiliation(s)
- Aleksandrs Prokofjevs
- Department of Chemistry, University of Michigan, 930 N. University Ave, Ann Arbor, MI 48109 (USA).
- Current address: Department of Chemistry, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208 (USA).
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41
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Prokofjevs A. Thermal Dehydrogenation of Base‐Stabilized B
2
H
5
+
Complexes and Its Role in CH Borylation. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201507647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Aleksandrs Prokofjevs
- Department of Chemistry, University of Michigan, 930 N. University Ave, Ann Arbor, MI 48109 (USA)
- Current address: Department of Chemistry, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208 (USA)
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42
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Metters OJ, Chapman AM, Robertson APM, Woodall CH, Gates PJ, Wass DF, Manners I. Generation of aminoborane monomers RR'N=BH2 from amine-boronium cations [RR'NH-BH2L](+): metal catalyst-free formation of polyaminoboranes at ambient temperature. Chem Commun (Camb) 2015; 50:12146-9. [PMID: 25177756 DOI: 10.1039/c4cc05145a] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Protonation of MeRNH·BH3 (R = Me or H) with HX (X = B(C6F5)4, OTf, or Cl), followed by immediate, spontaneous H2 elimination, yielded the amine-boronium cation salt [MeRNH·BH2(OEt2)][B(C6F5)4] and related polar covalent analogs, MeRNH·BH2X (X = OTf or Cl). These species can be deprotonated to conveniently generate reactive aminoborane monomers MeRN=BH2 which oligomerize or polymerize; in the case of MeNH2·BH3, the two step process gave poly(N-methylaminoborane), [MeNH-BH2]n.
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Affiliation(s)
- Owen J Metters
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
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43
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Curless LD, Clark ER, Cid J, Del Grosso A, Ingleson MJ. Complete reductive cleavage of CO facilitated by highly electrophilic borocations. Chem Commun (Camb) 2015; 51:10903-6. [DOI: 10.1039/c5cc03504j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
CO undergoes complete reductive cleavage using highly electrophilic hydride bridged borocations to ultimately yield trimethylboroxine and the boronium salt.
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Affiliation(s)
| | - Ewan R. Clark
- Department of Chemistry
- University of Manchester
- Manchester
- UK
| | - Jessica Cid
- Department of Chemistry
- University of Manchester
- Manchester
- UK
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44
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Ghadwal RS, Schürmann CJ, Andrada DM, Frenking G. Mono- and di-cationic hydrido boron compounds. Dalton Trans 2015. [DOI: 10.1039/c5dt02237a] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Stable mono- and di-cationic hydrido boron compounds featuring CH2BH2(μ-H)BH2CH2 and CH2BH(μ-H)2BHCH2 cores are readily accessible by dehydrogenative hydride abstractions. NBO calculations revealed the occurrence of two B–H–B 3c–2e bonds in the HB(μ-H)2BH moiety of di-cations (7 and 8), where 43% is located at the H bridges and ∼28% at each boron atom.
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Affiliation(s)
- Rajendra S. Ghadwal
- Institut für Anorganische Chemie
- Universität Bielefeld
- 33615 Bielefeld
- Germany
- Institut für Anorganische Chemie der Georg-August-Universität Göttingen
| | - Christian J. Schürmann
- Institut für Anorganische Chemie der Georg-August-Universität Göttingen
- 37077 Göttingen
- Germany
| | - Diego M. Andrada
- Fachbereich Chemie
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
| | - Gernot Frenking
- Fachbereich Chemie
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
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45
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46
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Arnold PL, Bell NL, Marr IH, She S, Hamilton J, Fraser C, Wang K. Protonolysis and thermolysis reactions of functionalised NHC-carbene boranes and borates. Dalton Trans 2014; 43:15419-28. [PMID: 25188908 DOI: 10.1039/c4dt01464b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A set of β-ketoimidazolium and β-ketoimidazolinium salts of the general formula [R(1)C(O)CH2{CH[NCR(3)CR(3)N(R(2))]}]X (R(1) = (t)Bu, naphth; R(2) = (i)Pr, Mes, (t)Bu; R(3) = H, Me, (H)2; X = Cl, Br) show contrasting reactivity with superhydride bases MHBEt3; two are reduced to chiral β-alcohol carbene-boranes R(1)CH(OH)CH2{C(BEt3)[NCR(3)CR(3)N(R(2))]} 2 (R(1) = (t)Bu; R(2) = (i)Pr, Mes; R(3) = H), two with bulky R(2) substituents are reduced to chiral β-borate imidazolium salts [R(1)CH(OBEt3)CH2{CH[NCR(3)CR(3)N(R(2))]}]X 3 (R(1) = (t)Bu, naphth; R(2) = Mes, (t)Bu; R(3) = H, Me; X = Cl, Br), and the two saturated heterocycle derivatives remain unreduced but form carbene-borane adducts R(1)C(O)CH2{C(BEt3)[NCR(3)CR(3)N(R(2))]} 4 (R(1) = (t)Bu, naphth; R(2) = Mes; R(3) = (H)2). Heating solutions of the imidazolium borates 3 results in the elimination of ethane, in the first example of organic borates functioning as Brønsted bases and forming carbene boranes R(1)CH(OBEt2)CH2{C[NCR(3)CR(3)N(R(2))]} 5 (R(1) = naphth; R(2) = Mes; R(3) = Me). The 'abnormal' carbene borane of the form 2 R(1)CH(OH)CH2{CH[NC(BEt3)CR(3)N(R(2))]} (R(1) = (t)Bu; R(2) = (t)Bu; R(3) = H), is also accessible by thermolysis of 3, suggesting that the carbene-borane alcohol is a more thermodynamically stable combination than the zwitterionic imidazolium borate. High-temperature thermolysis also can result in complete cleavage of the alcohol arm, eliminating tert-butyloxirane and forming the B-N bound imidazolium borate 7. The strong dependence of reaction products on the steric and electronic properties of each imidazole precursor molecule is discussed.
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Affiliation(s)
- Polly L Arnold
- EaStCHEM School of Chemistry, University of Edinburgh, The King's Buildings, Edinburgh, EH9 3JJ, UK.
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47
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Do DCH, Muthaiah S, Ganguly R, Vidović D. Synthesis of N-Heterocyclic Carbene Stabilized Catecholatoborenium Cations by Ligand Substitution. Organometallics 2014. [DOI: 10.1021/om500434r] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Dinh Cao Huan Do
- SPMS-CBC, Nanyang Technological University, 21 Nanyang Link, Singapore, 638737
| | | | - Rakesh Ganguly
- SPMS-CBC, Nanyang Technological University, 21 Nanyang Link, Singapore, 638737
| | - Dragoslav Vidović
- SPMS-CBC, Nanyang Technological University, 21 Nanyang Link, Singapore, 638737
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48
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He G, Shynkaruk O, Lui MW, Rivard E. Small Inorganic Rings in the 21st Century: From Fleeting Intermediates to Novel Isolable Entities. Chem Rev 2014; 114:7815-80. [DOI: 10.1021/cr400547x] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Gang He
- Department of Chemistry, University of Alberta, 11227 Saskatchewan
Drive, Edmonton, Alberta, Canada T6G 2G2
| | - Olena Shynkaruk
- Department of Chemistry, University of Alberta, 11227 Saskatchewan
Drive, Edmonton, Alberta, Canada T6G 2G2
| | - Melanie W. Lui
- Department of Chemistry, University of Alberta, 11227 Saskatchewan
Drive, Edmonton, Alberta, Canada T6G 2G2
| | - Eric Rivard
- Department of Chemistry, University of Alberta, 11227 Saskatchewan
Drive, Edmonton, Alberta, Canada T6G 2G2
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49
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Chen WC, Lee CY, Lin BC, Hsu YC, Shen JS, Hsu CP, Yap GPA, Ong TG. The Elusive Three-Coordinate Dicationic Hydrido Boron Complex. J Am Chem Soc 2014; 136:914-7. [DOI: 10.1021/ja4120852] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Wen-Ching Chen
- Institute
of Chemistry, Academia Sinica, Nangang, Taipei, Taiwan, Republic of China
| | - Ching-Yu Lee
- Institute
of Chemistry, Academia Sinica, Nangang, Taipei, Taiwan, Republic of China
- Department
of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, Republic of China
| | - Bo-Chao Lin
- Institute
of Chemistry, Academia Sinica, Nangang, Taipei, Taiwan, Republic of China
| | - Yu-Chen Hsu
- Institute
of Chemistry, Academia Sinica, Nangang, Taipei, Taiwan, Republic of China
| | - Jiun-Shian Shen
- Institute
of Chemistry, Academia Sinica, Nangang, Taipei, Taiwan, Republic of China
| | - Chao-Ping Hsu
- Institute
of Chemistry, Academia Sinica, Nangang, Taipei, Taiwan, Republic of China
| | - Glenn P. A. Yap
- Department
of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Tiow-Gan Ong
- Institute
of Chemistry, Academia Sinica, Nangang, Taipei, Taiwan, Republic of China
- The
Department of Applied Chemistry, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
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50
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Tay MQY, Murugesapandian B, Lu Y, Ganguly R, Rei K, Vidović D. Dihaloborenium cations stabilized by a four-membered N-heterocyclic carbene: electron deficiency compensation by asymmetric structural changes. Dalton Trans 2014; 43:15313-6. [DOI: 10.1039/c4dt01210k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Coordination of the four membered carbene ligand to electron deficient dihaloborenium moieties has resulted in asymmetric structural changes for the ligand's CN2P cyclic fragment.
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Affiliation(s)
| | | | - Yunpeng Lu
- SPMS-CBC
- Nanyang Technological University
- , Singapore
| | | | - Kinjo Rei
- SPMS-CBC
- Nanyang Technological University
- , Singapore
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