1
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Herbstritt D, Tomar P, Braun T. Activation of SF 5CF 3 by the N-Heterocyclic Carbene SIMes. Molecules 2023; 28:6693. [PMID: 37764468 PMCID: PMC10535660 DOI: 10.3390/molecules28186693] [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: 08/24/2023] [Revised: 09/06/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
The greenhouse gas SF5CF3 was photochemically activated with SIMes (1,3-Bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene) to give 1,3-dimesityl-2,2-difluoroimidazolidine (SIMesF2), and 1,3-dimesitylimidazolidine-2-sulfide, as well as the trifluoromethylated carbene derivative 1,3-dimesityl-2-fluoro-2-trifluoromethylimidazolidine. CF3 radicals, as well as SF4, serve presumably as intermediates of the conversions. In addition, the photochemical activation of SF5CF3 was performed in the presence of triphenylphosphine. The formation of triphenyldifluorophosphorane and triphenylphosphine sulfide was observed.
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Affiliation(s)
| | | | - Thomas Braun
- Department of Chemistry, Humboldt–Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany
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2
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Rahman MM, Meng G, Bisz E, Dziuk B, Lalancette R, Szostak R, Szostak M. I tOct (I tOctyl) - pushing the limits of I tBu: highly hindered electron-rich N-aliphatic N-heterocyclic carbenes. Chem Sci 2023; 14:5141-5147. [PMID: 37206400 PMCID: PMC10189875 DOI: 10.1039/d3sc01006f] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/15/2023] [Indexed: 05/21/2023] Open
Abstract
ItBu (ItBu = 1,3-di-tert-butylimidazol-2-ylidene) represents the most important and most versatile N-alkyl N-heterocyclic carbene available in organic synthesis and catalysis. Herein, we report the synthesis, structural characterization and catalytic activity of ItOct (ItOctyl), C2-symmetric, higher homologues of ItBu. The new ligand class, including saturated imidazolin-2-ylidene analogues has been commercialized in collaboration with MilliporeSigma: ItOct, 929 298; SItOct, 929 492 to enable broad access of the academic and industrial researchers within the field of organic and inorganic synthesis. We demonstrate that replacement of the t-Bu side chain with t-Oct results in the highest steric volume of N-alkyl N-heterocyclic carbenes reported to date, while retaining the electronic properties inherent to N-aliphatic ligands, such as extremely strong σ-donation crucial to the reactivity of N-alkyl N-heterocyclic carbenes. An efficient large-scale synthesis of imidazolium ItOct and imidazolinium SItOct carbene precursors is presented. Coordination chemistry to Au(i), Cu(i), Ag(i) and Pd(ii) as well as beneficial effects on catalysis using Au(i), Cu(i), Ag(i) and Pd(ii) complexes are described. Considering the tremendous importance of ItBu in catalysis, synthesis and metal stabilization, we anticipate that the new class of ItOct ligands will find wide application in pushing the boundaries of new and existing approaches in organic and inorganic synthesis.
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Affiliation(s)
- Md Mahbubur Rahman
- Department of Chemistry, Rutgers University 73 Warren Street Newark NJ 07102 USA
| | - Guangrong Meng
- Department of Chemistry, Rutgers University 73 Warren Street Newark NJ 07102 USA
| | - Elwira Bisz
- Department of Chemistry, Opole University 48 Oleska Street Opole 45-052 Poland
| | - Błażej Dziuk
- Department of Chemistry, Wroclaw University of Science and Technology Norwida 4/6 14 Wroclaw 50-373 Poland
| | - Roger Lalancette
- Department of Chemistry, Rutgers University 73 Warren Street Newark NJ 07102 USA
| | - Roman Szostak
- Department of Chemistry, Wroclaw University F. Joliot-Curie 14 Wroclaw 50-383 Poland
| | - Michal Szostak
- Department of Chemistry, Rutgers University 73 Warren Street Newark NJ 07102 USA
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3
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Zhang ZF, Su MD. Insights into the Reactivity of the Ring-Opening Reaction of Tetrahydrofuran by Intramolecular Group-13/P- and Al/Group-15-Based Frustrated Lewis Pairs. ACS OMEGA 2023; 8:5316-5331. [PMID: 36816703 PMCID: PMC9933199 DOI: 10.1021/acsomega.2c06194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 01/12/2023] [Indexed: 06/18/2023]
Abstract
A theoretical study concerning key factors affecting activation energies for ring-opening reactions of tetrahydrofuran (THF) by G13/P-based (G13 = B, Al, Ga, In, and Tl) and Al/G15-based (G15 = N, P, As, Sb, and Bi) frustrated Lewis pairs (FLPs) featuring the dimethylxanthene scaffold was performed using density functional theory. Our theoretical findings indicate that only dimethylxanthene backbone Al/P-Rea (Rea = reactant) FLP-type molecules can be energetically favorable to undergo the ring-opening reaction with THF. Our theoretical evidence reveals that the shorter the separating distance between Lewis acidic (LA) and Lewis basic (LB) centers of the dimethylxanthene backbone FLP-type molecules, the greater the orbital overlaps between the FLP and THF and the lower the activation barrier for such a ring-opening reaction. Energy decomposition analysis (EDA) evidence suggests that the bonding interaction for such a ring-opening reaction is predominated by the donor-acceptor interaction (singlet-singlet interaction) compared to the electron-sharing interaction (triplet-triplet interaction). In addition, the natural orbitals for chemical valence (NOCV) evidence demonstrate that the bonding situations of such ring-opening reactions can be best described as FLP-to-THF forward bonding (the lone pair (G15) → the empty σ*(C-O)) and THF-to-FLP back bonding (the empty σ*(G13) ← filled p-π(O)). The EDA-NOCV observations show that the former plays a predominant role and the latter plays a minor role in such bonding conditions. The activation strain model reveals that the deformation energy of THF is the key factor in determining the activation energy of their ring-opening reactions. Comparing the geometrical structures of the transition states with their corresponding reactants, a linear relationship between them can be rationally explained by the Hammond postulate combined with the respective activation barriers calculated in this work.
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Affiliation(s)
- Zheng-Feng Zhang
- Department
of Applied Chemistry, National Chiayi University, Chiayi60004, Taiwan
| | - Ming-Der Su
- Department
of Applied Chemistry, National Chiayi University, Chiayi60004, Taiwan
- Department
of Medicinal and Applied Chemistry, Kaohsiung
Medical University, Kaohsiung80708, Taiwan
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4
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STRUCTURE AND STABILITY OF MCl4 CARBENE COMPLEXES (M = Si, Ge, Sn): EXPERIMENT AND THEORY. J Organomet Chem 2022. [DOI: 10.1016/j.jorganchem.2022.122551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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5
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Abstract
In this paper, we have used a saturated five-membered N-Heterocyclic carbene (5SIDipp = 1,3-bis-(2,6-diisopropylphenyl)imidazolin-2-ylidine) for the synthesis of SNHC-haloboranes adducts and their further nucleophilic substitutions to put unusual functional groups at the central boron atom. The reaction of 5-SIDipp with RBCl2 yields Lewis-base adducts, 5-SIDipp·RBCl2 [R = H (1), Ph (2)]. The hydrolysis of 1 gives the NHC stabilized boric acid, 5-SIDipp·B(OH)3 (3), selectively. Replacement of chlorine atoms from 1 and 2 with one equivalent of AgOTf led to the formation of 5-SIDipp·HBCl(OTf) (4) and 5-SIDipp·PhBCl(OTf) (5a), where all the substituents on the boron atoms are different. The addition of two equivalents of AgNO3 to 2 leads to the formation of rare di-nitro substituted 5-SIDipp·BPh(NO3)2 (6). Further, the reaction of 5-SIDipp with B(C6F5)3 in tetrahydrofuran and diethyl ether shows a frustrated Lewis pair type small molecule activated products, 7 and 8.
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6
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Jupp AR. Evidence for the encounter complex in frustrated Lewis pair chemistry. Dalton Trans 2022; 51:10681-10689. [PMID: 35412552 DOI: 10.1039/d2dt00655c] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Frustrated Lewis Pairs (FLPs) are combinations of bulky Lewis acids and bases that can carry out small-molecule activation and catalysis. Mechanistically, the reaction of the acid, base and substrate involves the collision of three distinct molecules, and so the pre-association of the acid and base to form an encounter complex has been proposed. This article will examine the evidence for the formation of this encounter complex, focusing on the archetypal main-group combinations P(tBu)3/B(C6F5)3 and PMes3/B(C6F5)3 (Mes = mesityl), and includes quantum chemical calculations, molecular dynamics simulations, NMR spectroscopic measurements and neutron scattering. Furthermore, the recent discovery that the associated acid and base can absorb a photon to promote single-electron transfer has enabled the encounter complex to also be studied by UV-Vis spectroscopy, EPR spectroscopy, transient absorption spectroscopy, and resonance Raman spectroscopy. These data all support the notion that the encounter complex is only weakly held together and in low concentration in solution. The insights that these studies provide underpin the exciting transformations that can be promoted by FLPs. Finally, some observations and unanswered questions are provided to prompt further study in this field.
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Affiliation(s)
- Andrew R Jupp
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, West Midlands, B15 2TT, UK.
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7
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Horton TAR, Wang M, Shaver MP. Polymeric frustrated Lewis pairs in CO 2/cyclic ether coupling catalysis. Chem Sci 2022; 13:3845-3850. [PMID: 35432910 PMCID: PMC8966658 DOI: 10.1039/d2sc00894g] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 03/08/2022] [Indexed: 11/21/2022] Open
Abstract
Frustrated Lewis pairs (FLPs) are now ubiquitous as metal-free catalysts in an array of different chemical transformations. In this paper we show that this reactivity can be transferred to a polymeric system, offering advantageous opportunities at the interface between catalysis and stimuli-responsive materials. Formation of cyclic carbonates from cyclic ethers using CO2 as a C1 feedstock continues to be dominated by metal-based systems. When paired with a suitable nucleophile, discrete aryl or alkyl boranes have shown significant promise as metal-free Lewis acidic alternatives, although catalyst reuse remains illusive. Herein, we leverage the reactivity of FLPs in a polymeric system to promote CO2/cyclic ether coupling catalysis that can be tuned for the desired epoxide or oxetane substrate. Moreover, these macromolecular FLPs can be reused across multiple reaction cycles, further increasing their appeal over analogous small molecule systems.
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Affiliation(s)
- Thomas A R Horton
- Department of Materials, School of Natural Sciences, The University of Manchester Manchester UK
- Sustainable Materials Innovation Hub, Royce Hub Building, The University of Manchester Oxford Road Manchester UK
| | - Meng Wang
- Department of Materials, School of Natural Sciences, The University of Manchester Manchester UK
- Sustainable Materials Innovation Hub, Royce Hub Building, The University of Manchester Oxford Road Manchester UK
| | - Michael P Shaver
- Department of Materials, School of Natural Sciences, The University of Manchester Manchester UK
- Sustainable Materials Innovation Hub, Royce Hub Building, The University of Manchester Oxford Road Manchester UK
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8
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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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9
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Kundu G, Dixit R, Tothadi S, Vanka K, Sen SS. Versatile chemistry of six-membered NHC with boranes: bromination at sp3 borane, activation of B–H bond of HBpin, and ring expansion of NHC. Dalton Trans 2022; 51:14452-14457. [DOI: 10.1039/d2dt01707e] [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
The NHC•borane chemistry has been majorly restricted to imidazol-2-ylidene classes of carbenes. In our previous communication, we have reported the synthesis of 6-SIDipp•BH3 [6-SIDipp = 1,3-di(2,6-diisopropylphenyl) tetrahydropyrimidine-2-ylidene] and its electrophilic...
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10
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Federmann P, Herwig C, Beckmann F, Cula B, Limberg C. Ring-Opening of THF via an Intramolecular P/Al-Based Frustrated Lewis Pair: Assistance by C6F5 Groups beyond Electronegativity? Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00596] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Patrick Federmann
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Christian Herwig
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Fabian Beckmann
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Beatrice Cula
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Christian Limberg
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
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11
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Yolsal U, Horton TAR, Wang M, Shaver MP. Cyclic Ether Triggers for Polymeric Frustrated Lewis Pair Gels. J Am Chem Soc 2021; 143:12980-12984. [PMID: 34387464 PMCID: PMC8397318 DOI: 10.1021/jacs.1c06408] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
Sterically hindered
Lewis acid and base centers are unable to form
Lewis adducts, instead forming frustrated Lewis pairs (FLPs), where
latent reactivity can be utilized for the activation of small molecules.
Applying FLP chemistry into polymeric frameworks transforms this chemistry
into responsive and functional materials. Here, we report a versatile
synthesis strategy for the preparation of macromolecular FLPs and
explore its potential with the ring-opening reactions of cyclic ethers.
Addition of the cyclic substrates triggered polymer network formation,
where the extent of cross-linking, strength of network, and reactivity
are tuned by the steric and electronic properties of the ethers. The
resultant networks behave like covalently cross-linked polymers, demonstrating
the versatility of FLPs to simultaneously tune both small-molecule
capture and mechanical properties of materials.
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Affiliation(s)
- Utku Yolsal
- Department of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester, M1 3BB, United Kingdom
| | - Thomas A R Horton
- Department of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester, M1 3BB, United Kingdom
| | - Meng Wang
- Department of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester, M1 3BB, United Kingdom
| | - Michael P Shaver
- Department of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester, M1 3BB, United Kingdom.,Sustainable Materials Innovation Hub, Henry Royce Institute, University of Manchester, Oxford Road, Manchester, M13 9BL, United Kingdom
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12
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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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13
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Frosch J, Koneczny M, Bannenberg T, Tamm M. Halogen Complexes of Anionic N-Heterocyclic Carbenes. Chemistry 2021; 27:4349-4363. [PMID: 33094865 PMCID: PMC7986712 DOI: 10.1002/chem.202004418] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Indexed: 12/12/2022]
Abstract
The lithium complexes [(WCA-NHC)Li(toluene)] of anionic N-heterocyclic carbenes with a weakly coordinating anionic borate moiety (WCA-NHC) reacted with iodine, bromine, or CCl4 to afford the zwitterionic 2-halogenoimidazolium borates (WCA-NHC)X (X=I, Br, Cl; WCA=B(C6 F5 )3 , B{3,5-C6 H3 (CF3 )2 }3 ; NHC=IDipp=1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene, or NHC=IMes=1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene). The iodine derivative (WCA-IDipp)I (WCA=B(C6 F5 )3 ) formed several complexes of the type (WCA-IDipp)I⋅L (L=C6 H5 Cl, C6 H5 Me, CH3 CN, THF, ONMe3 ), revealing its ability to act as an efficient halogen bond donor, which was also exploited for the preparation of hypervalent bis(carbene)iodine(I) complexes of the type [(WCA-IDipp)I(NHC)] and [PPh4 ][(WCA-IDipp)I(WCA-NHC)] (NHC=IDipp, IMes). The corresponding bromine complex [PPh4 ][(WCA-IDipp)2 Br] was isolated as a rare example of a hypervalent (10-Br-2) system. DFT calculations reveal that London dispersion contributes significantly to the stability of the bis(carbene)halogen(I) complexes, and the bonding was further analyzed by quantum theory of atoms in molecules (QTAIM) analysis.
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Affiliation(s)
- Jenni Frosch
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
| | - Marvin Koneczny
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
| | - Thomas Bannenberg
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
| | - Matthias Tamm
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
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14
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Krahfuss MJ, Radius U. N-Heterocyclic silylenes as ambiphilic activators and ligands. Dalton Trans 2021; 50:6752-6765. [DOI: 10.1039/d1dt00617g] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Recent developments of the use of N-heterocyclic silylenes (NHSis), higher homologues of Arduengo-carbenes, as ambiphilic activators and ligands are highlighted and a comparison of NHSi ligands with NHC and phosphine ligands is provided.
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Affiliation(s)
- Mirjam J. Krahfuss
- Institut für Anorganische Chemie
- Julius-Maximilians-Universität Würzburg
- D-97074 Würzburg
- Germany
| | - Udo Radius
- Institut für Anorganische Chemie
- Julius-Maximilians-Universität Würzburg
- D-97074 Würzburg
- Germany
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15
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Kundu G, Pahar S, Tothadi S, Sen SS. Stepwise Nucleophilic Substitution to Access Saturated N-heterocyclic Carbene Haloboranes with Boron–Methyl Bonds. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00691] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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
| | - Sanjukta Pahar
- 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
| | - Srinu Tothadi
- Organic 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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16
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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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17
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Andrews RJ, Stephan DW. Isolable Anionic, Neutral and Cationic Radicals from Reactions of N,N'-Dimesityldiamidocarbene and Lewis Acids. Chemistry 2020; 26:7194-7198. [PMID: 32149432 DOI: 10.1002/chem.202001191] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Indexed: 01/04/2023]
Abstract
B(C6 F5 )3 undergoes nucleophilic attack by N,N'-dimesityldiamidocarbene (DAC) with fluoride transfer to the boron center, resulting in a new zwitterion (1). This B-F fluoride can be replaced or abstracted to give the corresponding hydride (2) or triflate (3) derivatives or the corresponding cation (4). These species are reduced with KC8 or Cp2 Co to give isolable anionic and neutral radicals (5-8). Similarly, the [Ph3 C] cation undergoes nucleophilic attack by DAC resulting in the spontaneous formation of the radical cation (9).
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Affiliation(s)
- Ryan J Andrews
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON, M5S 3H4, Canada
| | - Douglas W Stephan
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON, M5S 3H4, Canada
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18
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Simon M, Radius M, Wagner HE, Breher F. Imidazolyl Alanes – Synthesis, Structures, and Reactivity Studies. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Martin Simon
- Institute of Inorganic Chemistry Division Molecular Chemistry Karlsruhe Institute of Technology (KIT) Engesserstr.15 76131 Karlsruhe Germany
| | - Michael Radius
- Institute of Inorganic Chemistry Division Molecular Chemistry Karlsruhe Institute of Technology (KIT) Engesserstr.15 76131 Karlsruhe Germany
| | - Hanna E. Wagner
- Institute of Inorganic Chemistry Division Molecular Chemistry Karlsruhe Institute of Technology (KIT) Engesserstr.15 76131 Karlsruhe Germany
| | - Frank Breher
- Institute of Inorganic Chemistry Division Molecular Chemistry Karlsruhe Institute of Technology (KIT) Engesserstr.15 76131 Karlsruhe Germany
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19
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Lee E, Pietrasiak E. Activation of C–F, Si–F, and S–F Bonds by N-Heterocyclic Carbenes and Their Isoelectronic Analogues. Synlett 2020. [DOI: 10.1055/s-0040-1707106] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Reactions involving C–F, Si–F, and S–F bond cleavage with N-heterocyclic carbenes and isoelectronic species are reviewed. Most examples involve activation of aromatic C–F bond via an SNAr pathway and nucleophilic substitution of fluorine in electron-deficient olefins. The mechanism of the C–F bond activation depends on the reaction partners and the reaction can proceed via addition–elimination, oxidative addition (concerted or stepwise) or metathesis. The adducts formed upon substitution find applications in organic synthesis, as ligands and as stable radical precursors, but in most cases, their full potential remains unexplored.1 Introduction1.1 The C–F Bond1.2 C–F Bond Activation: A Short Summary1.3 C–F Bond Activation: A Special Case of SNAr1.4 N-Heterocyclic Carbenes (NHCs)1.5 The Purpose of this Article2 C–F bond Activation in Acyl Fluorides3 Activation of Vinylic C–F Bonds4 Activation of Aromatic C–F Bonds5 X–F Bond Activation (X = S or Si)6 C–F Bond Activation by Main Group Compounds Isoelectronic with NHCs7 Conclusions and Outlook
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Affiliation(s)
- Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology
- Division of Advanced Materials Science, Pohang University of Science and Technology
| | - Ewa Pietrasiak
- Department of Chemistry, Pohang University of Science and Technology
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20
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Abstract
The reaction of bis(silylenyl)-substituted ferrocene 1 with two molar equivalents of BPh3 yields the corresponding bis(silylene-borane) Lewis adduct 2. The latter is capable to activate CO2 to furnish the borane-stabilized bis(silanone) 3 through mono-oxygenation of the dative SiII →B silicon centers under release of CO. Removal of BPh3 from 3 with PMe3 affords the corresponding 1,3,2,4-cyclodisiloxane and the Me3 P-BPh3 adduct. All isolated new compounds were characterized and their molecular structures were determined by single-crystal X-ray diffraction analyses.
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Affiliation(s)
- Marcel‐Philip Luecke
- Department of Chemistry: Metalorganics and Inorganic MaterialsTechnische Universität BerlinStrasse des 17. Juni 115, Sekr. C210623BerlinGermany
| | - Elron Pens
- Department of Chemistry: Metalorganics and Inorganic MaterialsTechnische Universität BerlinStrasse des 17. Juni 115, Sekr. C210623BerlinGermany
| | - Shenglai Yao
- Department of Chemistry: Metalorganics and Inorganic MaterialsTechnische Universität BerlinStrasse des 17. Juni 115, Sekr. C210623BerlinGermany
| | - Matthias Driess
- Department of Chemistry: Metalorganics and Inorganic MaterialsTechnische Universität BerlinStrasse des 17. Juni 115, Sekr. C210623BerlinGermany
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21
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Ho LP, Körner L, Bannenberg T, Tamm M. Chalcogen complexes of anionic N-heterocyclic carbenes. Dalton Trans 2020; 49:13207-13217. [DOI: 10.1039/d0dt02392b] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Chalcogen complexes of anionic N-heterocyclic carbenes were isolated as lithium salts and their protonation and oxidation were studied.
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Affiliation(s)
- Luong Phong Ho
- Institut für Anorganische und Analytische Chemie
- Technische Universität Braunschweig
- 38106 Brauschweig
- Germany
| | - Lukas Körner
- Institut für Anorganische und Analytische Chemie
- Technische Universität Braunschweig
- 38106 Brauschweig
- Germany
| | - Thomas Bannenberg
- Institut für Anorganische und Analytische Chemie
- Technische Universität Braunschweig
- 38106 Brauschweig
- Germany
| | - Matthias Tamm
- Institut für Anorganische und Analytische Chemie
- Technische Universität Braunschweig
- 38106 Brauschweig
- Germany
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22
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Nomura K, Nagai G, Nasr A, Tsutsumi K, Kawamoto Y, Koide K, Tamm M. Synthesis of Half-Titanocenes Containing Anionic N-Heterocyclic Carbenes That Contain a Weakly Coordinating Borate Moiety, Cp′TiX2(WCA-NHC), and Their Use as Catalysts for Ethylene (Co)polymerization. Organometallics 2019. [DOI: 10.1021/acs.organomet.8b00841] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Kotohiro Nomura
- Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Go Nagai
- Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Alexandre Nasr
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Ken Tsutsumi
- Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Yuta Kawamoto
- Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Koji Koide
- Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Matthias Tamm
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
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23
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Vallet AL, Lacôte E. Thiolation of NHC-boranes: influence of the substitution at boron. Org Biomol Chem 2019; 17:4234-4237. [PMID: 30951071 DOI: 10.1039/c9ob00578a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Several N-Heterocyclic Carbene (NHC)-boryl sulfides with B-substituents were prepared. The added steric hindrance leads to much improved selectivities as only the NHC-boryl mono-sulfides were obtained. The B-substituted NHC-boranes are also conducive to more selective S to N NHC-boryl shift, provided that the NHC used is not too sterically demanding.
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Affiliation(s)
- Anne-Laure Vallet
- ICSN-CNRS, Bâtiment 27, 1 avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France
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24
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Roesch P, Müller R, Dallmann A, Scholz G, Kaupp M, Braun T, Braun‐Cula B, Wittwer P. A Silylene–Borane Lewis Pair as a Tool for Trapping a Water Molecule: Silanol Formation and Dehydrogenation. Chemistry 2019; 25:4678-4682. [DOI: 10.1002/chem.201900481] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Indexed: 11/06/2022]
Affiliation(s)
- Philipp Roesch
- Department of ChemistryHumboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Robert Müller
- Institut für ChemieTechnische Universität Berlin, Theoretische Chemie/Quantenchemie, Sekr. C7 Straße des 17. Juni 135 10623 Berlin Germany
| | - André Dallmann
- Department of ChemistryHumboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Gudrun Scholz
- Department of ChemistryHumboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Martin Kaupp
- Institut für ChemieTechnische Universität Berlin, Theoretische Chemie/Quantenchemie, Sekr. C7 Straße des 17. Juni 135 10623 Berlin Germany
| | - Thomas Braun
- Department of ChemistryHumboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Beatrice Braun‐Cula
- Department of ChemistryHumboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Philipp Wittwer
- Department of ChemistryHumboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
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25
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26
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Ho LP, Nasr A, Jones PG, Altun A, Neese F, Bistoni G, Tamm M. London Dispersion Interactions in Pnictogen Cations [ECl
2
]
+
and [E=E]
2+
(E=P, As, Sb) Supported by Anionic
N
‐Heterocyclic Carbenes. Chemistry 2018; 24:18922-18932. [DOI: 10.1002/chem.201804714] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Indexed: 01/11/2023]
Affiliation(s)
- Luong Phong Ho
- Institut für Anorganische und Analytische ChemieTechnische Universität Braunschweig Hagenring 30 38106 Braunschweig Germany
| | - Alexandre Nasr
- Institut für Anorganische und Analytische ChemieTechnische Universität Braunschweig Hagenring 30 38106 Braunschweig Germany
| | - Peter G. Jones
- Institut für Anorganische und Analytische ChemieTechnische Universität Braunschweig Hagenring 30 38106 Braunschweig Germany
| | - Ahmet Altun
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Giovanni Bistoni
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Matthias Tamm
- Institut für Anorganische und Analytische ChemieTechnische Universität Braunschweig Hagenring 30 38106 Braunschweig Germany
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27
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Radius M, Breher F. α-Borylated Phosphorus Ylides (α-BCPs): Electronic Frustration within a C−B π-Bond Arising from the Competition for a Lone Pair of Electrons. Chemistry 2018; 24:15744-15749. [DOI: 10.1002/chem.201803823] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Indexed: 12/25/2022]
Affiliation(s)
- Michael Radius
- Institute of Inorganic Chemistry; Division Molecular Chemistry; Karlsruhe Institute of Technology (KIT); Engesserstr. 15 76131 Karlsruhe Germany
| | - Frank Breher
- Institute of Inorganic Chemistry; Division Molecular Chemistry; Karlsruhe Institute of Technology (KIT); Engesserstr. 15 76131 Karlsruhe Germany
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28
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Affiliation(s)
- Jan Paradies
- Department of Chemistry; University of Paderborn; Warburger Strasse 100 33098 Paderborn Germany
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29
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Krachko T, Nicolas E, Ehlers AW, Nieger M, Slootweg JC. Ring-opening of Epoxides Mediated by Frustrated Lewis Pairs. Chemistry 2018; 24:12669-12677. [DOI: 10.1002/chem.201801909] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 06/06/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Tetiana Krachko
- Van 't Hoff Institute for Molecular Sciences; University of Amsterdam; Science Park 904, P.O. Box 94157 1090 GD Amsterdam The Netherlands
| | - Emmanuel Nicolas
- Van 't Hoff Institute for Molecular Sciences; University of Amsterdam; Science Park 904, P.O. Box 94157 1090 GD Amsterdam The Netherlands
- Current address: NIMBE, CEA, CNRS; Université Paris-Saclay, CEA Saclay; 91191 Gif sur Yvette Cedex France
| | - Andreas W. Ehlers
- Van 't Hoff Institute for Molecular Sciences; University of Amsterdam; Science Park 904, P.O. Box 94157 1090 GD Amsterdam The Netherlands
- Department of Chemistry, Science Faculty; University of Johannesburg; P.O. Box 254 Auckland Park Johannesburg South Africa
| | - Martin Nieger
- Department of Chemistry; University of Helsinki; A. I. Virtasen aukio 1, P.O. Box 55 Helsinki Finland
| | - J. Chris Slootweg
- Van 't Hoff Institute for Molecular Sciences; University of Amsterdam; Science Park 904, P.O. Box 94157 1090 GD Amsterdam The Netherlands
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30
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Hernán-Gómez A, Uzelac M, Baillie SE, Armstrong DR, Kennedy AR, Fuentes MÁ, Hevia E. Molecular Manipulations of a Utility Nitrogen-Heterocyclic Carbene by Sodium Magnesiate Complexes and Transmetallation Chemistry with Gold Complexes. Chemistry 2018; 24:10541-10549. [PMID: 29750849 DOI: 10.1002/chem.201802008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Indexed: 01/17/2023]
Abstract
Expanding the scope and applications of anionic N-heterocyclic carbenes (NHCs), a novel series of magnesium NHC complexes is reported using a mixed sodium-magnesium approach. Sequential reactivity of classical imidazol- 2-ylidene carbene IPr with NaR and MgR2 (R=CH2 SiMe3 ) affords [(THF)3 Na(μ-IPr- )MgR2 (THF)] (2) [IPr- =:C{[N(2,6-iPr2 C6 H3 )]2 CHC] containing an anionic NHC ligand, whereas surprisingly sodium magnesiate [NaMgR3 ] fails to deprotonate IPr affording instead the redistribution coordination adduct [IPr2 Na2 MgR4 ] (1). Compound 2 undergoes selective C2-methylation when treated with MeOTf furnishing novel abnormal NHC complex [{aIPrMe MgR2 }2 ] (3). Dissolving 3 in THF led to the dissociation of this complex into MgR2 and aIPrMe with the latter isomerizing to the olefinic NHC IPr=CH2 . The ability of 2 and 3 to transfer their anionic and abnormal NHC ligands, respectively to AuI metal fragments has been investigated allowing the isolation and structural characterization of [RAu(μ-IPr- )MgR(THF)2 ] (4) and [aIPrMe AuR] (5) respectively. In both cases transfer of an alkyl R group is observed. However while 3 can also transfer its abnormal NHC ligand to give 5, in 4 the anionic NHC still remains coordinated to Mg via its C4 position, whereas the {AuR} fragment occupies the C2 position previously filled by a donor-solvated {Na(THF)3 }+ cation.
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Affiliation(s)
- Alberto Hernán-Gómez
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK
| | - Marina Uzelac
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK
| | - Sharon E Baillie
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK
| | - David R Armstrong
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK
| | - Alan R Kennedy
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK
| | - M Ángeles Fuentes
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK
| | - Eva Hevia
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK
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31
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Rottschäfer D, Ebeler F, Strothmann T, Neumann B, Stammler HG, Mix A, Ghadwal RS. The Viability of C5-Protonated- and C4,C5-Ditopic Carbanionic Abnormal NHCs: A New Dimension in NHC Chemistry. Chemistry 2018; 24:3716-3720. [DOI: 10.1002/chem.201800260] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Indexed: 01/10/2023]
Affiliation(s)
- Dennis Rottschäfer
- Anorganische Molekülchemie und Katalyse, Lehrstuhl für, Anorganische Chemie und Strukturchemie, Centrum für, Molekulare Materialien, Fakultät für Chemie; Universität Bielefeld; Universitätsstr. 25 33615 Bielefeld Germany
| | - Falk Ebeler
- Anorganische Molekülchemie und Katalyse, Lehrstuhl für, Anorganische Chemie und Strukturchemie, Centrum für, Molekulare Materialien, Fakultät für Chemie; Universität Bielefeld; Universitätsstr. 25 33615 Bielefeld Germany
| | - Till Strothmann
- Anorganische Molekülchemie und Katalyse, Lehrstuhl für, Anorganische Chemie und Strukturchemie, Centrum für, Molekulare Materialien, Fakultät für Chemie; Universität Bielefeld; Universitätsstr. 25 33615 Bielefeld Germany
| | - Beate Neumann
- Anorganische Molekülchemie und Katalyse, Lehrstuhl für, Anorganische Chemie und Strukturchemie, Centrum für, Molekulare Materialien, Fakultät für Chemie; Universität Bielefeld; Universitätsstr. 25 33615 Bielefeld Germany
| | - Hans-Georg Stammler
- Anorganische Molekülchemie und Katalyse, Lehrstuhl für, Anorganische Chemie und Strukturchemie, Centrum für, Molekulare Materialien, Fakultät für Chemie; Universität Bielefeld; Universitätsstr. 25 33615 Bielefeld Germany
| | - Andreas Mix
- Anorganische Molekülchemie und Katalyse, Lehrstuhl für, Anorganische Chemie und Strukturchemie, Centrum für, Molekulare Materialien, Fakultät für Chemie; Universität Bielefeld; Universitätsstr. 25 33615 Bielefeld Germany
| | - Rajendra S. Ghadwal
- Anorganische Molekülchemie und Katalyse, Lehrstuhl für, Anorganische Chemie und Strukturchemie, Centrum für, Molekulare Materialien, Fakultät für Chemie; Universität Bielefeld; Universitätsstr. 25 33615 Bielefeld Germany
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32
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Tirfoin R, Gilbert J, Kelly MJ, Aldridge S. Frustrated Lewis pairs incorporating the bifunctional Lewis acid 1,1'-fc{B(C 6F 5) 2} 2: reactivity towards small molecules. Dalton Trans 2018; 47:1588-1598. [PMID: 29323374 DOI: 10.1039/c7dt04136e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Applications of the bifunctional ferrocenediyl Lewis acid 1,1'-fc{B(C6F5)2}2 in frustrated Lewis pair (FLP) chemistry are described. The coordination (or otherwise) of a range of sterically encumbered C-, N- and P-centred Lewis bases has been investigated, with lutidine, tetramethylpiperidine, PPh3, PtBu3 and the expanded ring carbene 6Dipp being found to be sterically incapable of coordinate bond formation. The chemistry of a range of these FLPs in the presence of H2O, NH3, CO2 and cyclohexylisocyanate (CyNCO) has been investigated, with the patterns of reactivity identified including simple coordination chemistry, E-H bond cleavage and C-B insertion.
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Affiliation(s)
- Rémi Tirfoin
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, UKOX1 3QR.
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33
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Noroozi-Shad N, Gholizadeh M, Izadyar M, Eshghi H. Theoretical Evaluation of the Efficiency of Novel Frustrated Lewis Pairs in the cis-Hydrogenation Reaction of Dimethylacetylene. PROGRESS IN REACTION KINETICS AND MECHANISM 2017. [DOI: 10.3184/146867817x14954764850469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Frustrated Lewis pairs (FLPs) are the combination of Lewis acid and base motifs where steric hindrance prevents strong adduct formation. Accordingly, the ability of FLPs in small molecule activation and their capability in hydrogen cleavage led to their use in the hydrogenation of a wide range of unsaturated substrates. Here, we investigated theoretically the ability of three intramolecular phosphorus/boron FLPs as bifunctional catalysts in the metal-free hydrogenation of dimethylacetylene to cis-alkene. The mechanism of this hydrogenation reaction, based on the boron acceptor [including –OR substituents (B(OR)2), where R is an aliphatic or aromatic branch] and phosphorus donor, has been explored. Based on the results obtained, it was confirmed that the H2 splitting reaction and the formation of the phosphonium–borohydride motifs for these FLPs are endothermic. It has been shown that these FLPs have a moderate ability in H–H bond splitting. Also, the capability of the boron atom in FLPs on the hydrogenation reaction was investigated. The reduction steps of the mechanism showed an exothermic nature. This result revealed that the presence of the boron as a Lewis acid, with a very limited Lewis acidity, improves the catalytic hydrogenation reaction significantly. Finally, it was confirmed that the proposed FLPs in the cis-hydrogenation of alkynes will be effective.
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Affiliation(s)
- Nazanin Noroozi-Shad
- Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Mostafa Gholizadeh
- Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Mohammad Izadyar
- Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Hossein Eshghi
- Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
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34
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Skara G, De Vleeschouwer F, Geerlings P, De Proft F, Pinter B. Heterolytic Splitting of Molecular Hydrogen by Frustrated and Classical Lewis Pairs: A Unified Reactivity Concept. Sci Rep 2017; 7:16024. [PMID: 29167477 PMCID: PMC5700139 DOI: 10.1038/s41598-017-16244-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 11/09/2017] [Indexed: 12/20/2022] Open
Abstract
Using a set of state-of-the-art quantum chemical techniques we scrutinized the characteristically different reactivity of frustrated and classical Lewis pairs towards molecular hydrogen. The mechanisms and reaction profiles computed for the H2 splitting reaction of various Lewis pairs are in good agreement with the experimentally observed feasibility of H2 activation. More importantly, the analysis of activation parameters unambiguously revealed the existence of two reaction pathways through a low-energy and a high-energy transition state. An exhaustive scrutiny of these transition states, including their stability, geometry and electronic structure, reflects that the electronic rearrangement in low-energy transition states is fundamentally different from that of high-energy transition states. Our findings reveal that the widespread consensus mechanism of H2 splitting characterizes activation processes corresponding to high-energy transition states and, accordingly, is not operative for H2-activating systems. One of the criteria of H2-activation, actually, is the availability of a low-energy transition state that represents a different H2 splitting mechanism, in which the electrostatic field generated in the cavity of Lewis pair plays a critical role: to induce a strong polarization of H2 that facilities an efficient end-on acid-H2 interaction and to stabilize the charge separated "H+-H-" moiety in the transition state.
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Affiliation(s)
- Gabriella Skara
- Quantum Chemistry Group, Member of the QCMM VUB-UGent Alliance Research Group, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium
| | - Freija De Vleeschouwer
- Quantum Chemistry Group, Member of the QCMM VUB-UGent Alliance Research Group, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium.
| | - Paul Geerlings
- Quantum Chemistry Group, Member of the QCMM VUB-UGent Alliance Research Group, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium
| | - Frank De Proft
- Quantum Chemistry Group, Member of the QCMM VUB-UGent Alliance Research Group, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium
| | - Balazs Pinter
- Quantum Chemistry Group, Member of the QCMM VUB-UGent Alliance Research Group, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium.
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35
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Huo Y, Xu Y, Wang Z. A DFT Study on the Mechanism of the FLP-access to N-Arylazacycles from Cyclic Ethers: Sequential Activation of Two C–O Bonds. CHEM LETT 2017. [DOI: 10.1246/cl.170633] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Yan Huo
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Yi Xu
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Zhihong Wang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
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36
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Uzelac M, Kennedy AR, Hevia E. Trans-Metal-Trapping Meets Frustrated-Lewis-Pair Chemistry: Ga(CH 2SiMe 3) 3-Induced C-H Functionalizations. Inorg Chem 2017; 56:8615-8626. [PMID: 28485929 PMCID: PMC5549243 DOI: 10.1021/acs.inorgchem.7b00549] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Merging two topical themes in main-group chemistry, namely, cooperative bimetallics and frustrated-Lewis-pair (FLP) activity, this Forum Article focuses on the cooperativity-induced outcomes observed when the tris(alkyl)gallium compound GaR3 (R = CH2SiMe3) is paired with the lithium amide LiTMP (TMP = 2,2,6,6-tetramethylpiperidide) or the sterically hindered N-heterocyclic carbene (NHC) 1,3-bis(tert-butyl)imidazol-2-ylidene (ItBu). When some previously published work are drawn together with new results, unique tandem reactivities are presented that are driven by the steric mismatch between the individual reagents of these multicomponent reagents. Thus, the LiTMP/GaR3 combination, which on its own fails to form a cocomplex, functions as a highly regioselective base (LiTMP)/trap (GaR3) partnership for the metalation of N-heterocycles such as diazines, 1,3-benzoazoles, and 2-picolines in a trans-metal-trapping (TMT) process that stabilizes the emerging sensitive carbanions. Taking advantage of related steric incompatibility, a novel monometallic FLP system pairing GaR3 with ItBu has been developed for the activation of carbonyl compounds (via C═O insertion) and other molecules with acidic hydrogen atoms such as phenol and phenylacetylene. Shedding new light on how these non-cocomplexing partnerships operate and showcasing the potential of gallium reagents to engage in metalation reactions or FLP activations, areas where the use of this group 13 metal is scant, this Forum Article aims to stimulate more interest and activity toward the advancement of organogallium chemistry.
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Affiliation(s)
- Marina Uzelac
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde , Glasgow G1 1XL, U.K
| | - Alan R Kennedy
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde , Glasgow G1 1XL, U.K
| | - Eva Hevia
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde , Glasgow G1 1XL, U.K
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Winkler A, Freytag M, Jones PG, Tamm M. Isolation and Reactivity of a FrustratedN-Heterocyclic Carbene-Borane. Z Anorg Allg Chem 2016. [DOI: 10.1002/zaac.201600290] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Andrea Winkler
- Institut für Anorganische und Analytische Chemie; Technische Universität Braunschweig; Hagenring 30 38106 Braunschweig Germany
| | - Matthias Freytag
- Institut für Anorganische und Analytische Chemie; Technische Universität Braunschweig; Hagenring 30 38106 Braunschweig Germany
| | - Peter G. Jones
- Institut für Anorganische und Analytische Chemie; Technische Universität Braunschweig; Hagenring 30 38106 Braunschweig Germany
| | - Matthias Tamm
- Institut für Anorganische und Analytische Chemie; Technische Universität Braunschweig; Hagenring 30 38106 Braunschweig Germany
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Uzelac M, Armstrong DR, Kennedy AR, Hevia E. Understanding the Subtleties of Frustrated Lewis Pair Activation of Carbonyl Compounds by N-Heterocyclic Carbene/Alkyl Gallium Pairings. Chemistry 2016; 22:15826-15833. [DOI: 10.1002/chem.201603597] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Marina Uzelac
- WestCHEM, Department of Pure and Applied Chemistry; University of Strathclyde; 295 Cathedral Street Glasgow G1 1XL UK
| | - David R. Armstrong
- WestCHEM, Department of Pure and Applied Chemistry; University of Strathclyde; 295 Cathedral Street Glasgow G1 1XL UK
| | - Alan R. Kennedy
- WestCHEM, Department of Pure and Applied Chemistry; University of Strathclyde; 295 Cathedral Street Glasgow G1 1XL UK
| | - Eva Hevia
- WestCHEM, Department of Pure and Applied Chemistry; University of Strathclyde; 295 Cathedral Street Glasgow G1 1XL UK
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Nasr A, Winkler A, Tamm M. Anionic N-heterocyclic carbenes: Synthesis, coordination chemistry and applications in homogeneous catalysis. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2016.02.011] [Citation(s) in RCA: 171] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Igarashi A, Kolychev EL, Tamm M, Nomura K. Synthesis of (Imido)Vanadium(V) Dichloride Complexes Containing Anionic N-Heterocyclic Carbenes That Contain a Weakly Coordinating Borate Moiety: New MAO-Free Ethylene Polymerization Catalysts. Organometallics 2016. [DOI: 10.1021/acs.organomet.6b00200] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Atsushi Igarashi
- Department
of Chemistry, Tokyo Metropolitan University, 1-1 Minami Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Eugene L. Kolychev
- Institut
für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Matthias Tamm
- Institut
für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Kotohiro Nomura
- Department
of Chemistry, Tokyo Metropolitan University, 1-1 Minami Osawa, Hachioji, Tokyo 192-0397, Japan
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Winkler A, Brandhorst K, Freytag M, Jones PG, Tamm M. Palladium(II) Complexes with Anionic N-Heterocyclic Carbene–Borate Ligands as Catalysts for the Amination of Aryl Halides. Organometallics 2016. [DOI: 10.1021/acs.organomet.6b00217] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andrea Winkler
- Institut für Anorganische
und Analytische Chemie, Technische Universität Braunschweig, Hagenring
30, 38106 Braunschweig, Germany
| | - Kai Brandhorst
- Institut für Anorganische
und Analytische Chemie, Technische Universität Braunschweig, Hagenring
30, 38106 Braunschweig, Germany
| | - Matthias Freytag
- Institut für Anorganische
und Analytische Chemie, Technische Universität Braunschweig, Hagenring
30, 38106 Braunschweig, Germany
| | - Peter G. Jones
- Institut für Anorganische
und Analytische Chemie, Technische Universität Braunschweig, Hagenring
30, 38106 Braunschweig, Germany
| | - Matthias Tamm
- Institut für Anorganische
und Analytische Chemie, Technische Universität Braunschweig, Hagenring
30, 38106 Braunschweig, Germany
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Bhattacharjee R, Nijamudheen A, Karmakar S, Datta A. Strain Control: Reversible H2 Activation and H2/D2 Exchange in Pt Complexes. Inorg Chem 2016; 55:3023-9. [PMID: 26958700 DOI: 10.1021/acs.inorgchem.5b02904] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rameswar Bhattacharjee
- Department
of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur 700032, West Bengal, India
| | - Abdulrahiman Nijamudheen
- Department
of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur 700032, West Bengal, India
| | - Sharmistha Karmakar
- Department
of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur 700032, West Bengal, India
| | - Ayan Datta
- Department
of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur 700032, West Bengal, India
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Szeto KC, Sahyoun W, Merle N, Castelbou JL, Popoff N, Lefebvre F, Raynaud J, Godard C, Claver C, Delevoye L, Gauvin RM, Taoufik M. Development of silica-supported frustrated Lewis pairs: highly active transition metal-free catalysts for the Z-selective reduction of alkynes. Catal Sci Technol 2016. [DOI: 10.1039/c5cy01372k] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Supported Lewis acid/base systems based have been prepared and characterized.
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Ai P, Danopoulos AA, Braunstein P. Transition metal (Rh and Fe) complexes and main-group (Se and B) adducts with N,N′-diphosphanyl NHC ligands: a study of stereoelectronic properties. Dalton Trans 2016; 45:4771-9. [DOI: 10.1039/c6dt00318d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The reactions ofN,N′-bis(di-tert-butylphosphanyl)-imidazole-2-ylidene (PCNHCP) with [Rh(μ-Cl)(COD)]2, [Rh(μ-Cl)(CO)2]2, [Fe4Cl8(THF)6], elemental Se and [(C6F5)BO]3, have been investigated to evaluate the stereoelectronic properties of this hybrid ligand.
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Affiliation(s)
- Pengfei Ai
- Laboratoire de Chimie de Coordination
- Institut de Chimie (UMR 7177 CNRS)
- Université de Strasbourg
- 67081 Strasbourg Cedex
- France
| | - Andreas A. Danopoulos
- Laboratoire de Chimie de Coordination
- Institut de Chimie (UMR 7177 CNRS)
- Université de Strasbourg
- 67081 Strasbourg Cedex
- France
| | - Pierre Braunstein
- Laboratoire de Chimie de Coordination
- Institut de Chimie (UMR 7177 CNRS)
- Université de Strasbourg
- 67081 Strasbourg Cedex
- France
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Scope and Mechanisms of Frustrated Lewis Pair Catalyzed Hydrogenation Reactions of Electron-Deficient CC Double Bonds. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201507298] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Morozova V, Mayer P, Berionni G. Scope and Mechanisms of Frustrated Lewis Pair Catalyzed Hydrogenation Reactions of Electron-Deficient C=C Double Bonds. Angew Chem Int Ed Engl 2015; 54:14508-12. [PMID: 26493512 DOI: 10.1002/anie.201507298] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Indexed: 11/09/2022]
Abstract
Several phosphonium and ammonium triarylborohydrides, which are intermediates in hydrogenation reactions catalyzed by frustrated Lewis pairs, were synthesized in high yield under mild conditions from triaryl boranes, ammonium or phosphonium halides, and triethylsilane. The kinetics and mechanisms of the reactions of these hydridoborate salts with benzhydrylium ions, iminium ions, quinone methides, and Michael acceptors were investigated, and their nucleophilicity was determined and compared with that of other hydride donors.
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Affiliation(s)
- Varvara Morozova
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München (Germany) http://www.cup.uni-muenchen.de/oc/mayr/
| | - Peter Mayer
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München (Germany) http://www.cup.uni-muenchen.de/oc/mayr/
| | - Guillaume Berionni
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München (Germany) http://www.cup.uni-muenchen.de/oc/mayr/.
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Arduengo III AJ, Calabrese JC, Marshall WJ, Runyon JW, Schiel C, Schinnen C, Tamm M, Uchiyama Y. Imidazol-2-ylidene Reactivity towards Cyanocarbons. Z Anorg Allg Chem 2015. [DOI: 10.1002/zaac.201500578] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Yang S, Zhang C. Theoretical Investigation of Obtaining Compounds with Planar Tetracoordinate Carbons by Frustrated Lewis Pairs. J Phys Chem A 2015. [PMID: 26218898 DOI: 10.1021/acs.jpca.5b06449] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ten derivatives of 2-borabicyclo[1.1.0]but-1(3)-ene (1a-1j) with different degrees of frustration have been investigated using density functional theory. Moreover, 1a-1j as Lewis bases were used to form Lewis adducts C3X2BYH/B(C6F5)3 (2a-2j) with Lewis acid B(C6F5)3. Optimized geometries and the thermodynamic properties of giving the Lewis adducts C3X2BYH/B(C6F5)3 reveal that 2a-2j are frustrated Lewis pairs (FLPs). Their reactivity of activating H2 and HF show that 2a-2j are unfavorable to heterolytically cleave H2, whereas 2c-2j can cleave HF to form [C3X2BYH](+)[FB(C6F5)3](-). In addition, we found the structures of [C3X2BYH](+) in [C3X2BYH](+)[FB(C6F5)3](-) contained a planar tetracoordinate carbon (ptC). Therefore, a new method of obtaining main group element compounds with ptC by using FLPs was presented.
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