1
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Werner L, Radius U. NHC aluminum chemistry on the rise. Dalton Trans 2024. [PMID: 39225565 DOI: 10.1039/d4dt01660b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
This perspective highlights recent developments of the use of N-heterocyclic carbenes (NHCs) and cyclic (alkyl)(amino)carbenes (cAACs) in alane and aluminum organyl chemistry. Especially in the last few years this flourishing research field led to some remarkable discoveries including various substitution patterns at the central aluminum atom, different oxidation states, neutral and charged compounds with varying coordination numbers and unique reactivities. Thereby NHCs play a vital role in the stabilization of these otherwise highly reactive compounds, which would not be realizable without the use of this intriguing class of ligands. Nevertheless, main group hydrides and especially NHC ligated alanes also tend to undergo NHC decomposition reactions, which are part of ongoing research and provide important information for NHC research in general.
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Affiliation(s)
- Luis Werner
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Udo Radius
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
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2
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Chowdhury T, Murphy F, Kennedy AR, Wilson C, Farnaby JH, Weetman CE. Synthesis and Reactivity of Bis-tris(pyrazolyl)borate Lanthanide/Aluminum Heterobimetallic Trihydride Complexes. Inorg Chem 2024; 63:9390-9394. [PMID: 38682828 PMCID: PMC11134492 DOI: 10.1021/acs.inorgchem.4c00824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/23/2024] [Accepted: 04/23/2024] [Indexed: 05/01/2024]
Abstract
Molecular heterobimetallic hydride complexes of lanthanide (Ln) and main-group (MG) metals exhibit chemical properties unique from their monometallic counterparts and are highly reactive species, making their synthesis and isolation challenging. Herein, molecular Ln/Al heterobimetallic trihydrides [Ln(Tp)2(μ-H)2Al(H)(N″)] [2-Ln; Ln = Y, Sm, Dy, Yb; Tp = hydrotris(1-pyrazolyl)borate; N″ = N(SiMe3)2] have been synthesized by facile insertion of aminoalane [Me3N·AlH3] into the Ln-N amide bonds of [Ln(Tp)2(N″)] (1-Ln). Thus, this is a simple synthetic strategy to access a range of Ln/Al hydrides. Reactivity studies demonstrate that 2-Ln is a heterobimetallic hydride, with evidence for the cooperative nature of 2-Ln shown by the catalytic amine-borane dehydrocoupling under ambient conditions in contrast to its monomeric counterparts.
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Affiliation(s)
- Tajrian Chowdhury
- Joseph
Black Building, School of Chemistry, University
of Glasgow, Glasgow G12 8QQ, U.K.
| | - Fáinché Murphy
- Department
of Pure and Applied Chemistry, University
of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, U.K.
| | - Alan R. Kennedy
- Department
of Pure and Applied Chemistry, University
of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, U.K.
| | - Claire Wilson
- Joseph
Black Building, School of Chemistry, University
of Glasgow, Glasgow G12 8QQ, U.K.
| | - Joy H. Farnaby
- Joseph
Black Building, School of Chemistry, University
of Glasgow, Glasgow G12 8QQ, U.K.
| | - Catherine E. Weetman
- Department
of Pure and Applied Chemistry, University
of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, U.K.
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3
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Werner L, Radius U. How to Decarbonize N-Heterocyclic Carbenes (NHCs): The simple Alane Adducts (NHC) ⋅ AlR 3 (R=H, Me, Et). Angew Chem Int Ed Engl 2024; 63:e202403639. [PMID: 38446008 DOI: 10.1002/anie.202403639] [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: 02/22/2024] [Revised: 02/27/2024] [Accepted: 02/27/2024] [Indexed: 03/07/2024]
Abstract
The reaction of the amine-stabilized alane (NMe3) ⋅ AlH3 1 with the backbone-saturated N-heterocyclic carbene (NHC) SIDipp (SIDipp=1,3-bis-{2,6-di-iso-propyl-phenyl}-imidazolidin-2-ylidene) at 0 °C yielded the NHC alane adduct (SIDipp) ⋅ AlH3 2. Reaction at elevated temperatures or prolonged reaction at room temperature gave the product of a ring expansion reaction (RER) of the NHC, (NMe3) ⋅ AlH(RER-SIDippH2) 3 ⋅ (NMe3). Subsequent reaction of the latter with sterically less hindered NHCs (IMeMe {=1,3,4,5-tetramethyl-imidazolin-2-ylidene}, IiPrMe {=1,3-di-iso-propyl-4,5-dimethyl-imidazolin-2-ylidene}, and IiPr {=1,3-di-iso-propyl-imidazolin-2-ylidene}) afforded the NHC-stabilized RER-products (NHC) ⋅ AlH(RER-SIDippH2) 3 ⋅ (NHC) (NHC=IMeMe, IiPrMe, IiPr), while no reaction was observed with the sterically more demanding NHCs IDipp (=1,3-bis-{2,6-di-iso-propyl-phenyl}-imidazolin-2-ylidene), SIDipp and ItBu (=1,3-di-tert-butyl-imidazolin-2-ylidene). The compounds 3 ⋅ (NHC) were also obtained starting from (SIDipp) ⋅ AlH3 2 and NHC at room temperature. Heating solutions of (SIDipp) ⋅ AlH3 2 without additional base to 95 °C resulted in decarbonization of the NHC and substitution of the carbene carbon atom with aluminum hydride under loss of ethene. Subsequent dimerization afforded cis-[AlH{μ-N(Dipp)CH2CH2N(Dipp)}]2 4_dimer. Heating solutions of the NHC-ligated aluminum alkyls (SIDipp) ⋅ AlR3 2R (R=Me, Et) to 145 °C instead led to complete scission of the NHC backbone with evolution of ethene and isolation of the dialkylaluminium(III) amidinates {DippNC(R)NDipp}AlR2 5R (R=Me, Et).
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Affiliation(s)
- Luis Werner
- 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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4
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Werner L, Hagn J, Gerstner A, Radius U. NHC-ligated indenyl- and fluorenyl-substituted Alanes and Gallanes: synthons towards indenyl- and fluorenyl-bridged (AlC) n-heterocycles ( n = 2,3). Dalton Trans 2024; 53:5932-5946. [PMID: 38456748 DOI: 10.1039/d4dt00244j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
Indenyl-(Ind) and fluorenyl-(Fl) substituted NHC-stabilized alanes and gallanes (NHC)·EH2R 1-12 (NHC = IiPrMe, IiPr, IMeMe; E = Al, Ga; R = Ind, Fl) were prepared via reaction of the corresponding NHC-iodoalanes and -gallanes with LiInd and LiFl, respectively. Analogously, the alane adducts with two Ind/Fl substituents (NHC)·AlHR213-18 (NHC = IiPrMe, IiPr, IMeMe; R = Ind, Fl) were obtained by using two equivalents of LiInd/LiFl. Elimination of indene and fluorene was induced thermally affording unusual dimeric and trimeric NHC-alane adducts {(NHC)·AlH2}2-μ-Fl 19-20 and {(NHC)·AlH-μ-R}n21-23 (R = Ind, Fl; n = 2, 3) with bridging indenyl and fluorenyl ligands.
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Affiliation(s)
- Luis Werner
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Julika Hagn
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Alexander Gerstner
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Udo Radius
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
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5
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Zapf L, Riethmann M, Föhrenbacher SA, Finze M, Radius U. An easy-to-perform evaluation of steric properties of Lewis acids. Chem Sci 2023; 14:2275-2288. [PMID: 36873848 PMCID: PMC9977453 DOI: 10.1039/d3sc00037k] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 02/04/2023] [Indexed: 02/08/2023] Open
Abstract
Steric and electronic effects play a very important role in chemistry, as these effects influence the shape and reactivity of molecules. Herein, an easy-to-perform approach to assess and quantify steric properties of Lewis acids with differently substituted Lewis acidic centers is reported. This model applies the concept of the percent buried volume (%V Bur) to fluoride adducts of Lewis acids, as many fluoride adducts are crystallographically characterized and are frequently calculated to judge fluoride ion affinities (FIAs). Thus, data such as cartesian coordinates are often easily available. A list of 240 Lewis acids together with topographic steric maps and cartesian coordinates of an oriented molecule suitable for the SambVca 2.1 web application is provided, together with different FIA values taken from the literature. Diagrams of %V Bur as a scale for steric demand vs. FIA as a scale for Lewis acidity provide valuable information about stereo-electronic properties of Lewis acids and an excellent evaluation of steric and electronic features of the Lewis acid under consideration. Furthermore, a novel LAB-Rep model (Lewis acid/base repulsion model) is introduced, which judges steric repulsion in Lewis acid/base pairs and helps to predict if an arbitrary pair of Lewis acid and Lewis base can form an adduct with respect to their steric properties. The reliability of this model was evaluated in four selected case studies, which demonstrate the versatility of this model. For this purpose, a user-friendly Excel spreadsheet was developed and is provided in the ESI, which works with listed buried volumes of Lewis acids %V Bur_LA and of Lewis bases %V Bur_LB, and no results from experimental crystal structures or quantum chemical calculations are necessary to evaluate steric repulsion in these Lewis acid/base pairs.
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Affiliation(s)
- Ludwig Zapf
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany https://www.ak-radius.de https://go.uniwue.de/finze-group.,Institute for Sustainable Chemistry & Catalysis with Boron (ICB), Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Melanie Riethmann
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany https://www.ak-radius.de https://go.uniwue.de/finze-group.,Institute for Sustainable Chemistry & Catalysis with Boron (ICB), Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Steffen A Föhrenbacher
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany https://www.ak-radius.de https://go.uniwue.de/finze-group
| | - Maik Finze
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany https://www.ak-radius.de https://go.uniwue.de/finze-group.,Institute for Sustainable Chemistry & Catalysis with Boron (ICB), Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Udo Radius
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany https://www.ak-radius.de https://go.uniwue.de/finze-group
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6
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Philipp MSM, Bertermann R, Radius U. Activation of Ge-H and Sn-H Bonds with N-Heterocyclic Carbenes and a Cyclic (Alkyl)(amino)carbene. Chemistry 2023; 29:e202202493. [PMID: 36177710 PMCID: PMC10100474 DOI: 10.1002/chem.202202493] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Indexed: 01/14/2023]
Abstract
A study of the reactivity of several N-heterocyclic carbenes (NHCs) and the cyclic (alkyl)(amino)carbene 1-(2,6-di-iso-propylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene (cAACMe ) with the group 14 hydrides GeH2 Mes2 and SnH2 Me2 (Me=CH3 , Mes=1,3,5-(CH3 )3 C6 H2 ) is presented. The reaction of GeH2 Mes2 with cAACMe led to the insertion of cAACMe into one Ge-H bond to give cAACMe H-GeHMes2 (1). If 1,3,4,5-tetramethyl-imidazolin-2-ylidene (Me2 ImMe ) was used as the carbene, NHC-mediated dehydrogenative coupling occurred, which led to the NHC-stabilized germylene Me2 ImMe ⋅GeMes2 (2). The reaction of SnH2 Me2 with cAACMe also afforded the insertion product cAACMe H-SnHMe2 (3), and reaction of two equivalents Me2 ImMe with SnH2 Me2 gave the NHC-stabilized stannylene Me2 ImMe ⋅SnMe2 (4). If the sterically more demanding NHCs Me2 ImMe , 1,3-di-isopropyl-4,5-dimethyl-imidazolin-2-ylidene (iPr2 ImMe ) and 1,3-bis-(2,6-di-isopropylphenyl)-imidazolin-2-ylidene (Dipp2 Im) were employed, selective formation of cyclic oligomers (SnMe2 )n (5; n=5-8) in high yield was observed. These cyclic oligomers were also obtained from the controlled decomposition of cAACMe H-SnHMe2 (3).
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Affiliation(s)
- Michael S M Philipp
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Rüdiger Bertermann
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Udo Radius
- Institute of Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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7
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Philipp MSM, Bertermann R, Radius U. N-heterocyclic carbene and cyclic (alkyl)(amino)carbene adducts of plumbanes and plumbylenes. Dalton Trans 2022; 51:13488-13498. [PMID: 35997066 DOI: 10.1039/d2dt02462d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lewis-acid/base adducts of N-heterocyclic carbenes (NHCs) and the cyclic (alkyl)(amino)carbene cAACMe (1-(2,6-di-iso-propylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene) with selected lead(II) and lead(IV) compounds are presented. The reaction of the NHCs Me2ImMe (1,3,4,5-tetramethyl-imidazolin-2-ylidene), iPr2ImMe (1,3-di-isopropyl-4,5-dimethyl-imidazolin-2-ylidene), Dipp2Im (1,3-bis-(2,6-di-isopropylphenyl)-imidazolin-2-ylidene) and cAACMe (1-(2,6-di-iso-propylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene) with PbI2 yielded the NHC-containing plumbylenes NHC·PbI2 (NHC = Me2ImMe (1), iPr2ImMe (2), Dipp2Im (3) and cAACMe·PbI2 (4)). Using the Pb(IV) compound PbCl2Ph2, the plumbane adducts NHC·PbCl2Ph2 (NHC = Me2ImMe (5), iPr2ImMe (6), Dipp2Im (7)) and cAACMe·PbCl2Ph2 (8)) were isolated in high yields. Reduction of the lead(IV) adducts 5 and 6 with excess KC8 afforded the diaryl substituted plumbylenes Me2ImMe·PbPh2 (9) and iPr2ImMe·PbPh2 (10), which are stable in the solid state but decompose in solution.
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Affiliation(s)
- Michael S M Philipp
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Rüdiger Bertermann
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Udo Radius
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
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8
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Roy MMD, Omaña AA, Wilson ASS, Hill MS, Aldridge S, Rivard E. Molecular Main Group Metal Hydrides. Chem Rev 2021; 121:12784-12965. [PMID: 34450005 DOI: 10.1021/acs.chemrev.1c00278] [Citation(s) in RCA: 124] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
This review serves to document advances in the synthesis, versatile bonding, and reactivity of molecular main group metal hydrides within Groups 1, 2, and 12-16. Particular attention will be given to the emerging use of said hydrides in the rapidly expanding field of Main Group element-mediated catalysis. While this review is comprehensive in nature, focus will be given to research appearing in the open literature since 2001.
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Affiliation(s)
- Matthew M D Roy
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Alvaro A Omaña
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
| | - Andrew S S Wilson
- Department of Chemistry, University of Bath, Avon BA2 7AY, United Kingdom
| | - Michael S Hill
- Department of Chemistry, University of Bath, Avon BA2 7AY, United Kingdom
| | - Simon Aldridge
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Eric Rivard
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
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9
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Philipp MSM, Krahfuss MJ, Radacki K, Radius U. N‐Heterocyclic Carbene and Cyclic (Alkyl)(amino)carbene Adducts of Antimony(III). Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100632] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Michael S. M. Philipp
- Institute of Inorganic Chemistry Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Mirjam J. Krahfuss
- Institute of Inorganic Chemistry Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Krzysztof Radacki
- Institute of Inorganic Chemistry Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Udo Radius
- Institute of Inorganic Chemistry Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
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10
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Föhrenbacher SA, Zeh V, Krahfuss MJ, Ignat'ev NV, Finze M, Radius U. Tris(pentafluoroethyl)difluorophosphorane and
N
‐Heterocyclic Carbenes: Adduct Formation and Frustrated
Lewis
Pair Reactivity. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100183] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Steffen A. Föhrenbacher
- Institute of Inorganic Chemistry Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Vivien Zeh
- Institute of Inorganic Chemistry Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Mirjam J. Krahfuss
- Institute of Inorganic Chemistry Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Nikolai V. Ignat'ev
- Institute of Inorganic Chemistry Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institute for Sustainable Chemistry & Catalysis with Boron (ICB) Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Consultant Merck KGaA Frankfurter Straße 250 64293 Darmstadt Germany
| | - Maik Finze
- Institute of Inorganic Chemistry Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Institute for Sustainable Chemistry & Catalysis with Boron (ICB) Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Udo Radius
- Institute of Inorganic Chemistry Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
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11
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Gruden E, Tavčar G. Synthesis and characterization of partially substituted NHC supported alane adducts using triflate or chloride salts. Polyhedron 2021. [DOI: 10.1016/j.poly.2020.115009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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12
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Werner L, Horrer G, Philipp M, Lubitz K, Kuntze‐Fechner MW, Radius U. A General Synthetic Route to NHC‐Phosphinidenes: NHC‐mediated Dehydrogenation of Primary Phosphines. Z Anorg Allg Chem 2021. [DOI: 10.1002/zaac.202000405] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Luis Werner
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Günther Horrer
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Michael Philipp
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Katharina Lubitz
- 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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13
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Krahfuss MJ, Radius U. N
‐Heterocyclic Silylene Main Group Element Chemistry: Adduct Formation, Insertion into E−X Bonds and Cyclization of Organoazides. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000942] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Mirjam J. Krahfuss
- 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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14
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Hock A, Werner L, Riethmann M, Radius U. Bis‐NHC Aluminium and Gallium Dihydride Cations [(NHC)
2
EH
2
]
+
(E = Al, Ga). Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000720] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Andreas Hock
- Institut für Anorganische Chemie Julius‐Maximilians‐Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Luis Werner
- Institut für Anorganische Chemie Julius‐Maximilians‐Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Melanie Riethmann
- 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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15
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Hock A, Werner L, Luz C, Radius U. N-Heterocyclic carbene and cyclic (alkyl)(amino)carbene adducts of gallium hydrides, gallium chlorides and gallium hydrochlorides. Dalton Trans 2020; 49:11108-11119. [PMID: 32743616 DOI: 10.1039/d0dt02070b] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis and characterization of N-heterocyclic carbene (NHC) and cyclic (alkyl)(amino)carbene (cAAC) gallane and chlorogallane adducts of the type (NHC)·GaH3 (NHC = Me2ImMe1, iPr2Im 2, iPr2ImMe3 and Dipp2ImH4; Me2ImMe = 1,3,4,5-tetra-methyl-imidazolin-2-ylidene; R2Im = 1,3-di-organyl-imidazolin-2-ylidene; Dipp = 2,6-diisopropylphenyl; Dipp2ImH = 1,3-bis(2,6-diisopropylphenyl)-imidazolidin-2-ylidene), (NHC)·GaH2Cl (NHC = iPr2ImMe9, Dipp2Im 10 and Dipp2ImH11; iPr2ImMe = 1,3 diisopropyl-4,5-dimethyl-imidazolin-2-ylidene), (NHC)·GaHCl2 (NHC = iPr2ImMe12, Dipp2Im 13 and Dipp2ImH14) and (cAACMe)·GaHCl215 is reported. Compounds 1-3 and 9-11 are unstable in solution as heating to the boiling temperature of toluene (110 °C) leads to decomposition into elemental gallium and the corresponding dihydroaminal NHC-H2. The reaction of the mono-NHC adducts with a second equivalent of NHC also afforded decomposition and formation of NHC-H2, whereas the reaction of the NHC-stabilized gallanes with one equivalent cAACMe leads to an insertion of the cAACMe carbene carbon atom into the Ga-H bond. The synthesis and characterization of (NHC)·GaH2(cAACMeH) (NHC = Me2ImMe5, iPr2ImMe6 and Dipp2Im 7), the products of an oxidative addition of (NHC)·GaH3 to cAACMe, are presented. The adduct (Dipp2ImH)·GaH34 reacts with two equivalents of cAACMe under the release of Dipp2ImH and insertion of two cAACMe molecules into the Ga-H bond to give the bisalkylgallane (cAACMeH)2GaH 8. If one or two hydrogen atoms of the NHC gallane adducts are replaced with an electron-withdrawing chloride substituent, a selective insertion of cAACMe into the Ga-H bond occurs only for the adducts of sterically less demanding NHCs such as iPr2ImMe. The reaction of cAACMe with (iPr2ImMe)·GaH2Cl 9 and (iPr2ImMe)·GaHCl212 afforded (iPr2ImMe)·GaHCl(cAACMeH) 16 and (iPr2ImMe)·GaCl2(cAACMeH) 17. The reaction of cAACMe with (NHC)·GaHCl2 and (NHC)·GaH2Cl (NHC = Dipp2Im, Dipp2ImH), adducts of the sterically more demanding NHCs, leads to an extrusion of the NHC to (cAACMe)·GaHCl215 and (cAACMeH)2GaCl 18.
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Affiliation(s)
- Andreas Hock
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Luis Werner
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Christian Luz
- 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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16
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Chernyshev VM, Denisova EA, Eremin DB, Ananikov VP. The key role of R-NHC coupling (R = C, H, heteroatom) and M-NHC bond cleavage in the evolution of M/NHC complexes and formation of catalytically active species. Chem Sci 2020; 11:6957-6977. [PMID: 33133486 PMCID: PMC7553045 DOI: 10.1039/d0sc02629h] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 06/19/2020] [Indexed: 02/01/2023] Open
Abstract
Complexes of metals with N-heterocyclic carbene ligands (M/NHC) are typically considered the systems of choice in homogeneous catalysis due to their stable metal-ligand framework. However, it becomes obvious that even metal species with a strong M-NHC bond can undergo evolution in catalytic systems, and processes of M-NHC bond cleavage are common for different metals and NHC ligands. This review is focused on the main types of the M-NHC bond cleavage reactions and their impact on activity and stability of M/NHC catalytic systems. For the first time, we consider these processes in terms of NHC-connected and NHC-disconnected active species derived from M/NHC precatalysts and classify them as fundamentally different types of catalysts. Problems of rational catalyst design and sustainability issues are discussed in the context of the two different types of M/NHC catalysis mechanisms.
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Affiliation(s)
- Victor M Chernyshev
- Platov South-Russian State Polytechnic University (NPI) , Prosveschenya 132 , Novocherkassk , 346428 , Russia
| | - Ekaterina A Denisova
- N. D. Zelinsky Institute of Organic Chemistry , Russian Academy of Sciences , Leninsky Prospect 47 , 119991 Moscow , Russian Federation
| | - Dmitry B Eremin
- N. D. Zelinsky Institute of Organic Chemistry , Russian Academy of Sciences , Leninsky Prospect 47 , 119991 Moscow , Russian Federation
- The Bridge@USC , University of Southern California , 1002 Childs Way , Los Angeles , California 90089-3502 , USA
| | - Valentine P Ananikov
- Platov South-Russian State Polytechnic University (NPI) , Prosveschenya 132 , Novocherkassk , 346428 , Russia
- N. D. Zelinsky Institute of Organic Chemistry , Russian Academy of Sciences , Leninsky Prospect 47 , 119991 Moscow , Russian Federation
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17
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Tomar P, Braun T, Kemnitz E. Preparation of NHC Stabilized Al(III)fluorides: Fluorination of [(SIMes)AlMe
3
] with SF
4
or Me
3
SnF. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201900921] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Pooja Tomar
- Department of Chemistry Humboldt‐Universität zu Berlin Brook‐Taylor‐Str. 2 12489 Berlin Germany
| | - Thomas Braun
- Department of Chemistry Humboldt‐Universität zu Berlin Brook‐Taylor‐Str. 2 12489 Berlin Germany
| | - Erhard Kemnitz
- Department of Chemistry Humboldt‐Universität zu Berlin Brook‐Taylor‐Str. 2 12489 Berlin Germany
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