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Dhara D, Endres L, Krummenacher I, Arrowsmith M, Dewhurst RD, Engels B, Bertermann R, Finze M, Demeshko S, Meyer F, Fantuzzi F, Braunschweig H. Synthesis and Reactivity of a Dialane-Bridged Diradical. Angew Chem Int Ed Engl 2024; 63:e202401052. [PMID: 38415886 DOI: 10.1002/anie.202401052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/07/2024] [Accepted: 02/09/2024] [Indexed: 02/29/2024]
Abstract
Radicals of the lightest group 13 element, boron, are well established and observed in numerous forms. In contrast to boron, radical chemistry involving the heavier group 13 elements (aluminum, gallium, indium, and thallium) remains largely underexplored, primarily attributed to the formidable synthetic challenges associated with these elements. Herein, we report the synthesis and isolation of planar and twisted conformers of a doubly CAAC (cyclic alkyl(amino)carbene)-radical-substituted dialane. Extensive characterization through spectroscopic analyses and X-ray crystallography confirms their identity, while quantum chemical calculations support their open-shell nature and provide further insights into their electronic structures. The dialane-connected diradicals exhibit high susceptibility to oxidation, as evidenced by electrochemical measurements and reactions with o-chloranil and a variety of organic azides. This study opens a previously uncharted class of dialuminum systems to study, broadening the scope of diradical chemistry and its potential applications.
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Affiliation(s)
- Debabrata Dhara
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Lukas Endres
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Physical and Theoretical Chemistry Julius-Maximilians-Universität Würzburg, Emil-Fischer-Str. 42, 97074, Würzburg, Germany
| | - Ivo Krummenacher
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Merle Arrowsmith
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Rian D Dewhurst
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Bernd Engels
- Institute for Physical and Theoretical Chemistry Julius-Maximilians-Universität Würzburg, Emil-Fischer-Str. 42, 97074, Würzburg, Germany
| | - Rüdiger Bertermann
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Maik Finze
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Serhiy Demeshko
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstraße 4, 37077, Göttingen, Germany
| | - Franc Meyer
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstraße 4, 37077, Göttingen, Germany
| | - Felipe Fantuzzi
- School of Chemistry and Forensic Science, University of Kent, Canterbury, Park Wood Rd, CT2 7NH, United Kingdom
| | - Holger Braunschweig
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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Werner L, Hagn J, Radius U. NHC-Stabilized Dialanes(4) of Al 2 Mes 4. Chemistry 2023; 29:e202303111. [PMID: 37792718 DOI: 10.1002/chem.202303111] [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: 09/28/2023] [Revised: 09/29/2023] [Accepted: 10/02/2023] [Indexed: 10/06/2023]
Abstract
The synthesis and characterization of novel N-heterocyclic carbene (NHC) stabilized dialanes Al2 Mes4 as well as first investigations concerning the reactivity of these compounds are reported. The synthesis of these compounds proceeds via the mesityl-substituted alanes (NHC)⋅AlHMes2 (NHC=IMeMe {=1,3,4,5-tetramethyl-imidazolin-2-ylidene}, IiPrMe {=1,3-di-iso-propyl-4,5-dimethylimidazolin-2-ylidene}) and iodo-alanes (NHC)⋅AlIMes2 (NHC=IMeMe , IiPrMe ). Metallic reduction of (NHC)⋅AlIMes2 afforded the new NHC-stabilized dialanes (NHC)2 ⋅Al2 Mes4 (NHC=IMeMe , IiPrMe ). The NHC-ligated dialanes are thermally robust and storable synthons for the dialane Al2 Mes4 . First reactivity studies on (IMeMe )2 ⋅Al2 Mes4 towards small molecules confirm this, as this compound shows controlled and selective reactions with several substrates. Reaction with CuCl leads to oxidation of the dialane and formation of (IMeMe )⋅AlClMes2 , reactions with pyridine N-oxide and t Bu-N=C=S, respectively, gave the chalcogenide-bridged dimers {(IMeMe )⋅AlMes2 }2 -μ-E (E=O, S), and reaction with acetylene afforded the dimetallaacetylide {(IMeMe )⋅AlMes2 }2 -μ-(C≡C).
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Affiliation(s)
- Luis Werner
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Julika Hagn
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Udo Radius
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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Zhu H, Fujimori S, Kostenko A, Inoue S. Dearomatization of C 6 Aromatic Hydrocarbons by Main Group Complexes. Chemistry 2023; 29:e202301973. [PMID: 37535350 DOI: 10.1002/chem.202301973] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/01/2023] [Accepted: 08/03/2023] [Indexed: 08/04/2023]
Abstract
The dearomatization reaction is a powerful method for transformation of simple aromatic compounds to unique chemical architectures rapidly in synthetic chemistry. Over the past decades, the chemistry in this field has evolved significantly and various important organic compounds such as crucial bioactive molecules have been synthesized through dearomatization. In general, photochemical conditions or assistance by transition metals are required for dearomatization of rigid arenes. Recently, main-group elements, especially naturally abundant elements in the Earth's crust, have attracted attention as they have low toxicity and are cost-effective compared to the late transition metals. In recent decades, a variety of low-valent main-group molecules, which enable the activation of stable aromatic compounds under mild conditions, have been developed. This minireview highlights the developments in the chemistry of dearomatization of C6 aromatic hydrocarbons by main-group compounds leading to the formation of seven-membered EC6 (E=main-group elements) ring or cycloaddition products.
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Affiliation(s)
- Huaiyuan Zhu
- TUM School of Natural Sciences, Department of Chemistry, Catalysis Research Center and Institute of Silicon Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching bei München, Germany
| | - Shiori Fujimori
- TUM School of Natural Sciences, Department of Chemistry, Catalysis Research Center and Institute of Silicon Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching bei München, Germany
| | - Arseni Kostenko
- TUM School of Natural Sciences, Department of Chemistry, Catalysis Research Center and Institute of Silicon Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching bei München, Germany
| | - Shigeyoshi Inoue
- TUM School of Natural Sciences, Department of Chemistry, Catalysis Research Center and Institute of Silicon Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching bei München, Germany
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Banerjee S, Ballmann GM, Evans MJ, O'Reilly A, Kennedy AR, Fulton JR, Coles MP, Mulvey RE. Three Oxidative Addition Routes of Alkali Metal Aluminyls to Dihydridoaluminates and Reactivity with CO 2. Chemistry 2023; 29:e202301849. [PMID: 37429823 DOI: 10.1002/chem.202301849] [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: 06/22/2023] [Revised: 07/08/2023] [Accepted: 07/10/2023] [Indexed: 07/12/2023]
Abstract
Three distinct routes are reported to the soluble, dihydridoaluminate compounds, AM[Al(NONDipp )(H)2 ] (AM=Li, Na, K, Rb, Cs; [NONDipp ]2- =[O(SiMe2 NDipp)2 ]2- ; Dipp=2,6-iPr2 C6 H3 ) starting from the alkali metal aluminyls, AM[Al(NONDipp )]. Direct H2 hydrogenation of the heavier analogues (AM=Rb, Cs) produced the first examples of structurally characterized rubidium and caesium dihydridoaluminates, although harsh conditions were required for complete conversion. Using 1,4-cyclohexadiene (1,4-CHD) as an alternative hydrogen source in transfer hydrogenation reactions provided a lower energy pathway to the full series of products for AM=Li-Cs. A further moderation in conditions was noted for the thermal decomposition of the (silyl)(hydrido)aluminates, AM[Al(NONDipp )(H)(SiH2 Ph)]. Probing the reaction of Cs[Al(NONDipp )] with 1,4-CHD provided access to a novel inverse sandwich complex, [{Cs(Et2 O)}2 {Al(NONDipp )(H)}2 (C6 H6 )], containing the 1,4-dialuminated [C6 H6 ]2- dianion and representing the first time that an intermediate in the commonly utilized oxidation process of 1,4-CHD to benzene has been trapped. The synthetic utility of the newly installed Al-H bonds has been demonstrated by their ability to reduce CO2 under mild conditions to form the bis-formate AM[Al(NONDipp )(O2 CH)2 ] compounds, which exhibit a diverse series of eyecatching bimetallacyclic structures.
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Affiliation(s)
- Sumanta Banerjee
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, G1 1XL, Glasgow, UK
| | - Gerd M Ballmann
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, G1 1XL, Glasgow, UK
| | - Matthew J Evans
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6140, New Zealand
| | - Andrea O'Reilly
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6140, New Zealand
| | - Alan R Kennedy
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, G1 1XL, Glasgow, UK
| | - J Robin Fulton
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6140, New Zealand
| | - Martyn P Coles
- School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6140, New Zealand
| | - Robert E Mulvey
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, G1 1XL, Glasgow, UK
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Mandal D, Demirer TI, Sergeieva T, Morgenstern B, Wiedemann HTA, Kay CWM, Andrada DM. Evidence of Al II Radical Addition to Benzene. Angew Chem Int Ed Engl 2023; 62:e202217184. [PMID: 36594569 DOI: 10.1002/anie.202217184] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/23/2022] [Accepted: 01/03/2023] [Indexed: 01/04/2023]
Abstract
Electrophilic AlIII species have long dominated the aluminum reactivity towards arenes. Recently, nucleophilic low-valent AlI aluminyl anions have showcased oxidative additions towards arenes C-C and/or C-H bonds. Herein, we communicate compelling evidence of an AlII radical addition reaction to the benzene ring. The electron reduction of a ligand stabilized precursor with KC8 in benzene furnishes a double addition to the benzene ring instead of a C-H bond activation, producing the corresponding cyclohexa-1,3(orl,4)-dienes as Birch-type reduction product. X-ray crystallographic analysis, EPR spectroscopy, and DFT results suggest this reactivity proceeds through a stable AlII radical intermediate, whose stability is a consequence of a rigid scaffold in combination with strong steric protection.
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Affiliation(s)
- Debdeep Mandal
- General and Inorganic Chemistry Department, University of Saarland, Campus C4.1, 66123, Saarbrücken, Germany
| | - T Ilgin Demirer
- General and Inorganic Chemistry Department, University of Saarland, Campus C4.1, 66123, Saarbrücken, Germany
| | - Tetiana Sergeieva
- General and Inorganic Chemistry Department, University of Saarland, Campus C4.1, 66123, Saarbrücken, Germany
| | - Bernd Morgenstern
- General and Inorganic Chemistry Department, University of Saarland, Campus C4.1, 66123, Saarbrücken, Germany
| | - Haakon T A Wiedemann
- Physical Chemistry Department, University of Saarland, Campus B2.2, 66123, Saarbrücken, Germany
| | - Christopher W M Kay
- Physical Chemistry Department, University of Saarland, Campus B2.2, 66123, Saarbrücken, Germany.,London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London, WC1H 0AH, UK
| | - Diego M Andrada
- General and Inorganic Chemistry Department, University of Saarland, Campus C4.1, 66123, Saarbrücken, Germany
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Feng G, Chan KL, Lin Z, Yamashita M. Al-Sc Bonded Complexes: Synthesis, Structure, and Reaction with Benzene in the Presence of Alkyl Halide. J Am Chem Soc 2022; 144:22662-22668. [PMID: 36469934 DOI: 10.1021/jacs.2c09746] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
An alumanyl anion possessing N,N'-bis(2,6-diisopropylphenyl)-1,3-propanediamine ligand was synthesized and characterized. Transmetalation of this Al anion with diaminoscandium chloride precursors afforded the corresponding Al-Sc complexes possessing an unprecedented Al-Sc bond. The Al-Sc[N(SiMe3)2] complex underwent intramolecular C-H cleavage to form a bridged dinuclear complex with μ-hydrido and μ-methylene ligands. The Al-Sc(NiPr2)2 complex reacted with benzene in the presence of alkyl bromide to furnish a 1,4-dialuminated cyclohexadiene product with a concomitant formation of the alkyl-alkyl coupled product. Although the latter product seems to form through the radical mechanism, DFT calculations revealed an ionic mechanism involving bimetallic reaction pathways to react with alkyl bromide and benzene, which provides new insight into the chemistry of metal-metal bonded compounds.
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Affiliation(s)
- Genfeng Feng
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Aichi, Japan
| | - Ka Lok Chan
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Zhenyang Lin
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Makoto Yamashita
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Aichi, Japan
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Isaac CJ, Miloserdov FM, Pécharman AF, Lowe JP, McMullin CL, Whittlesey MK. Structure and Reactivity of [Ru–Al] and [Ru–Sn] Heterobimetallic PPh 3-Based Complexes. Organometallics 2022; 41:2716-2730. [PMID: 36249448 PMCID: PMC9554919 DOI: 10.1021/acs.organomet.2c00344] [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: 07/08/2022] [Indexed: 11/30/2022]
Abstract
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Treatment of [Ru(PPh3)(C6H4PPh2)2H][Li(THF)2] with AlMe2Cl and SnMe3Cl leads to elimination of LiCl and
CH4 and formation of the heterobimetallic complexes [Ru(C6H4PPh2)2{PPh2C6H4AlMe(THF)}H] 5 and [Ru(PPh3)(C6H4PPh2)(PPh2C6H4SnMe2)] 6, respectively.
The pathways to 5 and 6 have been probed
by variable temperature NMR studies, together with input from DFT
calculations. Complete reaction of H2 occurs with 5 at 60 °C and with 6 at room temperature
to yield the spectroscopically characterized trihydride complexes
[Ru(PPh2)2{PPh2C6H4AlMe}H3] 7 and [Ru(PPh2)2{PPh2C6H4SnMe2}H3] 8. In the presence of CO, 6 forms the acylated phosphine complex, [Ru(CO)2(C(O)C6H4PPh2)(PPh2C6H4SnMe2)] 9, through a series
of intermediates that were identified by NMR spectroscopy in conjunction
with 13CO labeling. Complex 6 undergoes addition
and substitution reactions with the N-heterocyclic carbene 1,3,4,5-tetramethylimidazol-2-ylidene
(IMe4) to give [Ru(IMe4)2(PPh2C6H4)(PPh2C6H4SnMe2)] 10, which converted via rare
N-Me group C–H activation to [Ru(IMe4)(PPh3)(IMe4)′(PPh2C6H4SnMe2)] 11 upon heating at 60 °C and
to a mixture of [Ru(IMe4)2(IMe4)′(PPh2C6H4SnMe2)] 12 and [Ru(PPh3)(PPh2C6H4)(IMe4-SnMe2)′] 13 at 120
°C.
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Affiliation(s)
- Connie J. Isaac
- Department of Chemistry, University of Bath, Bath BA2 7AY, U.K
| | | | | | - John P. Lowe
- Department of Chemistry, University of Bath, Bath BA2 7AY, U.K
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