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Scholz AS, Bolte M, Virovets A, Peresypkina E, Lerner HW, Anstöter CS, Wagner M. Tetramerization of BEB-Doped Phenalenyls to Obtain (BE) 8-[16]Annulenes (E = N, O). J Am Chem Soc 2024; 146:12100-12112. [PMID: 38635878 DOI: 10.1021/jacs.4c02163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2024]
Abstract
Two (BE)8-[16]annulenes were prepared and fully characterized by experimental and quantum-chemical means (1, E = N; 2, E = O). The 1,8-naphthalenediyl-bridged diborane(6) 3 served as their common starting material, which was treated with [Al(NH3)6]Cl3 to form 1 (91% yield) or with 1,8-naphthalenediboronic acid anhydride to form 2 (93% yield). As a result, the heteroannulenes 1 and 2 are supported by four aromatic "clamps" and may also be viewed as NH- or O-bridged cyclic tetramers of BNB- or BOB-doped phenalenyls. X-ray crystallography on mono-, di-, and tetraadducts 2·thf, 2·py2, and 2·py4 showed that 2 is an oligotopic Lewis acid (thf/py: tetrahydrofuran/pyridine donor). The applicability of 2 also as a Lewis basic ligand in coordination chemistry was demonstrated by the synthesis of the mononuclear Ag+ complex [Ag(py)2(2·py4)]+ and the dinuclear Pb2+ complex 6. During the assembly of 6, the rearrangement of 2 led to the formation of two (BO)9-macrocycles linked by two BOB-phenalenyls to form a nanometer-sized cage with four negatively charged, tetracoordinated B atoms. Both 1 and 2 show several redox waves in the cathodic regions of the cyclic voltammograms. An in-depth assessment of the consequences of electron injection on the aromaticity of 1 and 2 was achieved by electronic structure calculations. 1 and 2 are proposed to exhibit aromatic switching capabilities in the [16]annulene motif.
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Affiliation(s)
- Alexander S Scholz
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Michael Bolte
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Alexander Virovets
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Eugenia Peresypkina
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Hans-Wolfram Lerner
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Cate S Anstöter
- EaStCHEM School of Chemistry, University of Edinburgh, EH8 9YLEdinburgh,U.K
| | - Matthias Wagner
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
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Le Moigne L, Posenato T, Gajan D, Lesage de la Haye J, Raynaud J, Lacôte E. Catalyst-Free Transfer Hydrogenation from Amine-Borane Small Oligomers. Chemistry 2024; 30:e202300145. [PMID: 37814903 DOI: 10.1002/chem.202300145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 10/09/2023] [Accepted: 10/10/2023] [Indexed: 10/11/2023]
Abstract
Amine-borane dimers and oligomers with varied steric and electronic profiles were prepared via capping agent-controlled AA/BB polycondensations. They were used for transfer hydrogenations to aldehydes, ketones, imines as well as electron-poor alkene/alkyne moieties. The amine-borane Lewis-paired oligomers and the congested bis(amine-borane)s provided the highest yields. This was likely helped by facilitated dissociation (oligomers) or H-bond assistance. In the case of the oligomers, the second equivalent of H2 present was also engaged in the reaction. Solid-state NMR characterization provides evidence that the boron-containing materials obtained after transfer dehydrogenation are highly similar to those obtained from thermal dehydrogenation. The oligomers bridge the gap between simple amine-borane molecular reductants and the poly-amine-boranes and provide a full picture of the reactivity changes at the different scales.
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Affiliation(s)
- Louis Le Moigne
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, CNES, ArianeGroup, LHCEP, UMR 5278, Bât. Raulin, 2 rue Victor Grignard, 69622, Villeurbanne, France
| | - Tommaso Posenato
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, CPE Lyon, CP2 M -, UMR 5128, PolyCatMat, 43 Bd du 11 novembre 1918, 69616, Villeurbanne, France
| | - David Gajan
- Univ Lyon, CNRS, ENS de Lyon, Université Claude Bernard Lyon 1, Centre de RMN à Très Hauts Champs de Lyon, UMR5082, 5 Rue de la Doua, 69100, Villeurbanne, France
| | - Jennifer Lesage de la Haye
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, CNES, ArianeGroup, LHCEP, UMR 5278, Bât. Raulin, 2 rue Victor Grignard, 69622, Villeurbanne, France
| | - Jean Raynaud
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, CPE Lyon, CP2 M -, UMR 5128, PolyCatMat, 43 Bd du 11 novembre 1918, 69616, Villeurbanne, France
| | - Emmanuel Lacôte
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, CNES, ArianeGroup, LHCEP, UMR 5278, Bât. Raulin, 2 rue Victor Grignard, 69622, Villeurbanne, France
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3
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Cross MJ, Brodie CN, Crivoi DG, Goodall JC, Ryan DE, Martínez‐Martínez AJ, Johnson A, Weller AS. Dehydropolymerization of Amine-Boranes using Bis(imino)pyridine Rhodium Pre-Catalysis: σ-Amine-Borane Complexes, Nanoparticles, and Low Residual-Metal BN-Polymers that can be Chemically Repurposed. Chemistry 2023; 29:e202302110. [PMID: 37530441 PMCID: PMC10947130 DOI: 10.1002/chem.202302110] [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: 07/03/2023] [Revised: 07/31/2023] [Accepted: 08/02/2023] [Indexed: 08/03/2023]
Abstract
The sigma amine-borane complexes [Rh(L1)(η2 :η2 -H3 B⋅NRH2 )][OTf] (L1=2,6-bis-[1-(2,6-diisopropylphenylimino)ethyl]pyridine, R=Me, Et, n Pr) are described, alongside [Rh(L1)(NMeH2 )][OTf]. Using R=Me as a pre-catalyst (1 mol %) the dehydropolymerization of H3 B ⋅ NMeH2 gives [H2 BNMeH]n selectively. Added NMeH2 , or the direct use of [Rh(L1)(NMeH2 )][OTf], is required for initiation of catalysis, which is suggested to operate through the formation of a neutral hydride complex, Rh(L1)H. The formation of small (1-5 nm) nanoparticles is observed at the end of catalysis, but studies are ambiguous as to whether the catalysis is solely nanoparticle promoted or if there is a molecular homogeneous component. [Rh(L1)(NMeH2 )][OTf] is shown to operate at 0.025 mol % loadings on a 2 g scale of H3 B ⋅ NMeH2 to give polyaminoborane [H2 BNMeH]n [Mn =30,900 g/mol, Ð=1.8] that can be purified to a low residual [Rh] (6 μg/g). Addition of Na[N(SiMe3 )2 ] to [H2 BNMeH]n results in selective depolymerization to form the eee-isomer of N,N,N-trimethylcyclotriborazane [H2 BNMeH]3 : the chemical repurposing of a main-group polymer.
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Affiliation(s)
| | | | - Dana G. Crivoi
- Department of ChemistryUniversity of OxfordOxfordOX1 3TAUK
| | | | - David E. Ryan
- Department of ChemistryUniversity of YorkYorkYO10 5DDUK
- Department of ChemistryUniversity of OxfordOxfordOX1 3TAUK
| | - Antonio J. Martínez‐Martínez
- Department of ChemistryUniversity of OxfordOxfordOX1 3TAUK
- Supramolecular Organometallic and Main Group Chemistry Laboratory CIQSO-Center for Research in Sustainable Chemistry and Department of ChemistryUniversity of HuelvaCampus El Carmen21007HuelvaSpain
| | - Alice Johnson
- Department of ChemistryUniversity of OxfordOxfordOX1 3TAUK
- Department of Biosciences and ChemistrySheffield Hallam UniversityHoward StSheffieldS1 1WBUK
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Reuter MB, Seth DM, Javier-Jiménez DR, Finfer EJ, Beretta EA, Waterman R. Recent advances in catalytic pnictogen bond forming reactions via dehydrocoupling and hydrofunctionalization. Chem Commun (Camb) 2023; 59:1258-1273. [PMID: 36648191 DOI: 10.1039/d2cc06143k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
An examination of several catalytic reactions among the group 15 elements is presented. The connections between the chemistry of the pnictogens can sometimes be challenging, but aspects of metal-pnictogen reactivity are the key. The connecting reactivity comes from metal-catalyzed transformations such as dehydrocoupling and hydrofunctionalization. Pivotal mechanistic insights from E-N heterodehydrocoupling have informed the development of highly active catalysts for these reactions. Metal-amido nucleophilicity is often at the core of this reactivity, which diverges from phosphine and arsine dehydrocoupling. Nucleophilicity connects to the earliest understanding of hydrophosphination catalysis, but more recent catalysts are leveraging enhanced insertion activity through photolysis. This photocatalysis extends to hydroarsination, which may also have more metal-arsenido nucleophilicity than anticipated. However, metal-catalyzed arsinidene chemistry foreshadowed related phosphinidene chemistry by years. This examination shows the potential for greater influence of individual discoveries and understanding to leverage new advances between these elements, and it also suggests that the chemistry of heavier elements may have more influence on what is possible with lighter elements.
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Affiliation(s)
- Matthew B Reuter
- University of Vermont, Department of Chemistry, 82 University Place, Burlington, Vermont, USA.
| | - Dennis M Seth
- University of Vermont, Department of Chemistry, 82 University Place, Burlington, Vermont, USA.
| | - Diego R Javier-Jiménez
- University of Vermont, Department of Chemistry, 82 University Place, Burlington, Vermont, USA.
| | - Emma J Finfer
- University of Vermont, Department of Chemistry, 82 University Place, Burlington, Vermont, USA.
| | - Evan A Beretta
- University of Vermont, Department of Chemistry, 82 University Place, Burlington, Vermont, USA.
| | - Rory Waterman
- University of Vermont, Department of Chemistry, 82 University Place, Burlington, Vermont, USA.
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Peng C, Liu W, Wang Y. Mechanistic insights into H 3B·NMeH 2 dehydrogenation by Co-based complexes: a DFT perspective. NEW J CHEM 2023. [DOI: 10.1039/d2nj06155d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
Mechanistic insights into Co-catalyzed H3B·NMeH2 dehydrogenation and polyaminoborane formation are carefully investigated using density functional theory.
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Affiliation(s)
- Cheng Peng
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China
| | - Wei Liu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China
| | - Yong Wang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China
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6
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Brodie CN, Sotorrios L, Boyd TM, Macgregor SA, Weller AS. Dehydropolymerization of H 3B·NMeH 2 Mediated by Cationic Iridium(III) Precatalysts Bearing κ 3- iPr-PN RP Pincer Ligands ( R = H, Me): An Unexpected Inner-Sphere Mechanism. ACS Catal 2022; 12:13050-13064. [PMID: 36313521 PMCID: PMC9594342 DOI: 10.1021/acscatal.2c03778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/27/2022] [Indexed: 11/30/2022]
Abstract
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The dehydropolymerization of H3B·NMeH2 to form N-methylpolyaminoborane using neutral
and
cationic catalysts based on the {Ir(iPr-PNHP)} fragment [iPr-PNHP = κ3-(CH2CH2PiPr2)2NH] is reported. Neutral
Ir(iPr-PNHP)H3 or
Ir(iPr-PNHP)H2Cl
precatalysts show no, or poor and unselective, activity respectively
at 298 K in 1,2-F2C6H4 solution.
In contrast, addition of [NMeH3][BArF4] (ArF = 3,5-(CF3)2C6H3) to Ir(iPr-PNHP)H3 immediately starts catalysis, suggesting that a cationic
catalytic manifold operates. Consistent with this, independently synthesized
cationic precatalysts are active (tested between 0.5 and 2.0 mol %
loading) producing poly(N-methylaminoborane) with Mn ∼ 40,000 g/mol, Đ ∼1.5, i.e., dihydrogen/dihydride, [Ir(iPr-PNHP)(H)2(H2)][BArF4]; σ-amine-borane [Ir(iPr-PNHP)(H)2(H3B·NMe3)][BArF4]; and [Ir(iPr-PNHP)(H)2(NMeH2)][BArF4]. Density functional theory (DFT) calculations
probe hydride exchange processes in two of these complexes and also
show that the barrier to amine-borane dehydrogenation is lower (22.5
kcal/mol) for the cationic system compared with the neutral system
(24.3 kcal/mol). The calculations show that the dehydrogenation proceeds
via an inner-sphere process without metal–ligand cooperativity,
and this is supported experimentally by N–Me substituted [Ir(iPr-PNMeP)(H)2(H3B·NMe3)][BArF4] being
an active catalyst. Key to the lower barrier calculated for the cationic
system is the outer-sphere coordination of an additional H3B·NMeH2 with the N–H group of the ligand.
Experimentally, kinetic studies indicate a complex reaction manifold
that shows pronounced deceleratory temporal profiles. As supported
by speciation and DFT studies, a key observation is that deprotonation
of [Ir(iPr-NHP)(H)2(H2)][BArF4], formed upon amine-borane
dehydrogenation, by the slow in situ formation of NMeH2 (via B–N bond cleavage), results in the formation of essentially
inactive Ir(iPr-PNHP)H3, with a coproduct of [NMeH3]+/[H2B(NMeH2)2]+. While reprotonation
of Ir(iPr-PNHP)H3 results in a return to the cationic cycle, it is proposed, supported
by doping experiments, that reprotonation is attenuated by entrainment
of the [NMeH3]+/[H2B(NMeH2)2]+/catalyst in insoluble polyaminoborane.
The role of [NMeH3]+/[H2B(NMeH2)]+ as chain control agents is also noted.
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Affiliation(s)
| | - Lia Sotorrios
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Timothy M. Boyd
- Department of Chemistry, University of York, York YO10 5DD, U.K
- Chemistry Research Laboratories, University of Oxford, Oxford OX1 3TA, U.K
| | - Stuart A. Macgregor
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
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Omaña AA, Watt R, Zhou Y, Ferguson MJ, Rivard E. Frustrated Lewis Pair Chelation and Reactivity of Complexed Parent Iminoborane and Aminoborane. Inorg Chem 2022; 61:16430-16440. [PMID: 36197137 DOI: 10.1021/acs.inorgchem.2c02535] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An intramolecular phosphine-borane frustrated Lewis pair (FLP) chelate, iPr2P(C6H4)BCy2 or PB (Cy = cyclohexyl), was used to coordinate aminoborane (H2BNH2) and iminoborane (HBNH) units via donor-acceptor stabilization. Attempts to induce dehydrogenation from these B-N adducts with known metal catalysts (or pre-catalysts) have been unsuccessful thus far, and related observations were noted with an H2BNH2 complex supported by a modified FLP chelate bearing a geometrically constrained bicyclic 9-borabicyclo(3.3.1)nonane (BBN) unit. Treatment of the iminoborane adduct [PB{HBNH}] with a chlorinating agent led to ligand activation via B-C bond cleavage instead of the expected H/Cl exchange at boron to give [PB{ClBNH}]. Nucleophilic attack at the boron center in [PB{HBNH}] was observed upon addition of BnK (Bn = benzyl), yielding the amidoborate complex [PB{H(Bn)BNH}{K(THF)2}].
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Affiliation(s)
- Alvaro A Omaña
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta T6G 2G2, Canada
| | - Ryan Watt
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta T6G 2G2, Canada
| | - Yuqiao Zhou
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta T6G 2G2, Canada
| | - Michael J Ferguson
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta T6G 2G2, Canada
| | - Eric Rivard
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta T6G 2G2, Canada
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Babón JC, Esteruelas MA, Oñate E, Paz S, Vélez A. Silyl-Osmium(IV)-Trihydride Complexes Stabilized by a Pincer Ether-Diphosphine: Formation and Reactions with Alkynes. Organometallics 2022; 41:2022-2034. [PMID: 36866234 PMCID: PMC9969874 DOI: 10.1021/acs.organomet.2c00201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Indexed: 11/28/2022]
Abstract
Complex OsH4{κ3-P,O,P-[xant(PiPr2)2]} (1) activates the Si-H bond of triethylsilane, triphenylsilane, and 1,1,1,3,5,5,5-heptamethyltrisiloxane to give the silyl-osmium(IV)-trihydride derivatives OsH3(SiR3){κ3-P,O,P-[xant(PiPr2)2]} [SiR3 = SiEt3 (2), SiPh3 (3), SiMe(OSiMe3)2 (4)] and H2. The activation takes place via an unsaturated tetrahydride intermediate, resulting from the dissociation of the oxygen atom of the pincer ligand 9,9-dimethyl-4,5-bis(diisopropylphosphino)xanthene (xant(PiPr2)2). This intermediate, which has been trapped to form OsH4{κ2-P,P-[xant(PiPr2)2]}(PiPr3) (5), coordinates the Si-H bond of the silanes to subsequently undergo a homolytic cleavage. Kinetics of the reaction along with the observed primary isotope effect demonstrates that the Si-H rupture is the rate-determining step of the activation. Complex 2 reacts with 1,1-diphenyl-2-propyn-1-ol and 1-phenyl-1-propyne. The reaction with the former affords Os{C≡CC(OH)Ph2}2{=C=CHC(OH)Ph2}{κ3-P,O,P-[xant(PiPr2)2]} (6), which catalyzes the conversion of the propargylic alcohol into (E)-2-(5,5-diphenylfuran-2(5H)-ylidene)-1,1-diphenylethan-1-ol, via (Z)-enynediol. In methanol, the hydroxyvinylidene ligand of 6 dehydrates to allenylidene, generating Os{C≡CC(OH)Ph2}2{=C=C=CPh2}{κ3-P,O,P-[xant(PiPr2)2]} (7). The reaction of 2 with 1-phenyl-1-propyne leads to OsH{κ1-C,η2-[C6H4CH2CH=CH2]}{κ3-P,O,P-[xant(PiPr2)2]} (8) and PhCH2CH=CH(SiEt3).
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Race JJ, Webb MJ, Boyd TM, Weller AS. Ortho‐F,F‐DPEphos: Synthesis and Coordination Chemistry in Rhodium and Gold Complexes, and Comparison with DPEphos. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202200174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- James J. Race
- University of York Department of Chemistry YO10 5DD York UNITED KINGDOM
| | | | | | - Andrew S. Weller
- University of York Chemistry Heslington YO105DD York UNITED KINGDOM
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de las Heras LA, Esteruelas MA, Oliván M, Oñate E. C–Cl Oxidative Addition and C–C Reductive Elimination Reactions in the Context of the Rhodium-Promoted Direct Arylation. Organometallics 2022; 41:716-732. [PMID: 35368715 PMCID: PMC8966374 DOI: 10.1021/acs.organomet.1c00643] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Indexed: 01/09/2023]
Abstract
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A cycle of stoichiometric
elemental reactions defining the direct
arylation promoted by a redox-pair Rh(I)–Rh(III) is reported.
Starting from the rhodium(I)-aryl complex RhPh{κ3-P,O,P-[xant(PiPr2)2]} (xant(PiPr2)2 = 9,9-dimethyl-4,5-bis(diisopropylphosphino)xanthene),
the reactions include C–Cl oxidative addition of organic chlorides,
halide abstraction from the resulting six-coordinate rhodium(III)
derivatives, C–C reductive coupling between the initial aryl
ligand and the added organic group, oxidative addition of a C–H
bond of a new arene, and deprotonation of the generated hydride-rhodium(III)-aryl
species to form a new rhodium(I)-aryl derivative. In this context,
the kinetics of the oxidative additions of 2-chloropyridine, chlorobenzene,
benzyl chloride, and dichloromethane to RhPh{κ3-P,O,P-[xant(PiPr2)2]} and the C–C reductive
eliminations of biphenyl and benzylbenzene from [RhPh2{κ3-P,O,P-[xant(PiPr2)2]}]BF4 and [RhPh(CH2Ph){κ3-P,O,P-[xant(PiPr2)2]}]BF4, respectively,
have been studied. The oxidative additions generally involve the cis
addition of the C–Cl bond of the organic chloride to the rhodium(I)
complex, being kinetically controlled by the C–Cl bond dissociation
energy; the weakest C–Cl bond is faster added. The C–C
reductive elimination is kinetically governed by the dissociation
energy of the formed bond. The C(sp3)–C(sp2) coupling to give benzylbenzene
is faster than the C(sp2)–C(sp2) bond
formation to afford biphenyl. In spite of that a most demanding orientation
requirement is needed for the C(sp3)–C(sp2) coupling than for the C(sp2)–C(sp2) bond formation, the energetic effort for the pregeneration of the
C(sp3)–C(sp2) bond is lower. As a result,
the weakest C–C bond is formed faster.
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Affiliation(s)
- Laura A. de las Heras
- Departamento de Química Inorgánica─Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)─Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza─CSIC, 50009 Zaragoza, Spain
| | - Miguel A. Esteruelas
- Departamento de Química Inorgánica─Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)─Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza─CSIC, 50009 Zaragoza, Spain
| | - Montserrat Oliván
- Departamento de Química Inorgánica─Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)─Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza─CSIC, 50009 Zaragoza, Spain
| | - Enrique Oñate
- Departamento de Química Inorgánica─Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)─Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza─CSIC, 50009 Zaragoza, Spain
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11
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Ríos P, Rodríguez A, Conejero S. Activation of Si–H and B–H bonds by Lewis acidic transition metals and p-block elements: same, but different. Chem Sci 2022; 13:7392-7418. [PMID: 35872827 PMCID: PMC9241980 DOI: 10.1039/d2sc02324e] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/18/2022] [Indexed: 01/01/2023] Open
Abstract
In this Perspective we discuss the ability of transition metal complexes to activate and cleave the Si–H and B–H bonds of hydrosilanes and hydroboranes (tri- and tetra-coordinated) in an electrophilic manner, avoiding the need for the metal centre to undergo two-electron processes (oxidative addition/reductive elimination). A formal polarization of E–H bonds (E = Si, B) upon their coordination to the metal centre to form σ-EH complexes (with coordination modes η1 or η2) favors this type of bond activation that can lead to reactivities involving the formation of transient silylium and borenium/boronium cations similar to those proposed in silylation and borylation processes catalysed by boron and aluminium Lewis acids. We compare the reactivity of transition metal complexes and boron/aluminium Lewis acids through a series of catalytic reactions in which pieces of evidence suggest mechanisms involving electrophilic reaction pathways. In this Perspective we compare the ability of transition metals and p-block Lewis acids to activate electrophilically hydrosilanes and hydroboranes. The mechanistic similarities and dissimilarities in different catalytic transformations are analyzed.![]()
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Affiliation(s)
- Pablo Ríos
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica CSIC and Universidad de Sevilla, Centro de Innovación en Química Avanzada (ORFEO-CINQA), C/Américo Vespucio 49, 41092, Sevilla, Spain
| | - Amor Rodríguez
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica CSIC and Universidad de Sevilla, Centro de Innovación en Química Avanzada (ORFEO-CINQA), C/Américo Vespucio 49, 41092, Sevilla, Spain
| | - Salvador Conejero
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica CSIC and Universidad de Sevilla, Centro de Innovación en Química Avanzada (ORFEO-CINQA), C/Américo Vespucio 49, 41092, Sevilla, Spain
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12
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Brodie CN, Boyd TM, Sotorríos L, Ryan DE, Magee E, Huband S, Town JS, Lloyd-Jones GC, Haddleton DM, Macgregor SA, Weller AS. Controlled Synthesis of Well-Defined Polyaminoboranes on Scale Using a Robust and Efficient Catalyst. J Am Chem Soc 2021; 143:21010-21023. [PMID: 34846131 DOI: 10.1021/jacs.1c10888] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The air tolerant precatalyst, [Rh(L)(NBD)]Cl ([1]Cl) [L = κ3-(iPr2PCH2CH2)2NH, NBD = norbornadiene], mediates the selective synthesis of N-methylpolyaminoborane, (H2BNMeH)n, by dehydropolymerization of H3B·NMeH2. Kinetic, speciation, and DFT studies show an induction period in which the active catalyst, Rh(L)H3 (3), forms, which sits as an outer-sphere adduct 3·H3BNMeH2 as the resting state. At the end of catalysis, dormant Rh(L)H2Cl (2) is formed. Reaction of 2 with H3B·NMeH2 returns 3, alongside the proposed formation of boronium [H2B(NMeH2)2]Cl. Aided by isotopic labeling, Eyring analysis, and DFT calculations, a mechanism is proposed in which the cooperative "PNHP" ligand templates dehydrogenation, releasing H2B═NMeH (ΔG‡calc = 19.6 kcal mol-1). H2B═NMeH is proposed to undergo rapid, low barrier, head-to-tail chain propagation for which 3 is the catalyst/initiator. A high molecular weight polymer is formed that is relatively insensitive to catalyst loading (Mn ∼71 000 g mol-1; Đ, of ∼ 1.6). The molecular weight can be controlled using [H2B(NMe2H)2]Cl as a chain transfer agent, Mn = 37 900-78 100 g mol-1. This polymerization is suggested to arise from an ensemble of processes (catalyst speciation, dehydrogenation, propagation, chain transfer) that are geared around the concentration of H3B·NMeH2. TGA and DSC thermal analysis of polymer produced on scale (10 g, 0.01 mol % [1]Cl) show a processing window that allows for melt extrusion of polyaminoborane strands, as well as hot pressing, drop casting, and electrospray deposition. By variation of conditions in the latter, smooth or porous microstructured films or spherical polyaminoboranes beads (∼100 nm) result.
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Affiliation(s)
- Claire N Brodie
- Department of Chemistry, University of York, Heslington, York YO31 1ES, U.K
| | - Timothy M Boyd
- Department of Chemistry, University of York, Heslington, York YO31 1ES, U.K.,Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
| | - Lia Sotorríos
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - David E Ryan
- Department of Chemistry, University of York, Heslington, York YO31 1ES, U.K.,Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
| | - Eimear Magee
- International Institute for Nanocomposites Manufacturing, WMG, University of Warwick, Coventry CV4 7AL, U.K
| | - Steven Huband
- Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| | - James S Town
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Guy C Lloyd-Jones
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, Scotland, U.K
| | - David M Haddleton
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Stuart A Macgregor
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Andrew S Weller
- Department of Chemistry, University of York, Heslington, York YO31 1ES, U.K
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13
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Stroek W, Keilwerth M, Pividori DM, Meyer K, Albrecht M. An Iron-Mesoionic Carbene Complex for Catalytic Intramolecular C-H Amination Utilizing Organic Azides. J Am Chem Soc 2021; 143:20157-20165. [PMID: 34841864 DOI: 10.1021/jacs.1c07378] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The synthesis of N-heterocycles is of paramount importance for the pharmaceutical industry. They are often synthesized through atom economic and environmentally unfriendly methods, generating significant waste. A less explored, but greener, alternative is the synthesis through the direct intramolecular C-H amination utilizing organic azides. Few examples exist by using this method, but many are limited due to the required use of stoichiometric amounts of Boc2O. Herein, we report a homoleptic C,O-chelating mesoionic carbene-iron complex, which is the first iron-based complex that does not require the addition of any protecting groups for this transformation and that is active also in strong donor solvents such as THF or even DMSO. The achieved turnover number is an order of magnitude higher than any other reported catalytic system. A variety of C-H bonds were activated, including benzylic, primary, secondary, and tertiary. By following the reaction over time, we determined the presence of an initiation period. Kinetic studies showed a first-order dependence on substrate concentration and half-order dependence on catalyst concentration. Intermolecular competition reactions with deuterated substrate showed no KIE, while separate reactions with deuterium-labeled substrate resulted in a KIE of 2.0. Moreover, utilizing deuterated substrate significantly decreased the initiation period of the catalysis. Preliminary mechanistic studies suggest a unique mechanism involving a dimeric iron species as the catalyst resting state.
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Affiliation(s)
- Wowa Stroek
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, CH-3012 Bern, Switzerland
| | - Martin Keilwerth
- Department of Chemistry & Pharmacy, Inorganic Chemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | - Daniel M Pividori
- Department of Chemistry & Pharmacy, Inorganic Chemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | - Karsten Meyer
- Department of Chemistry & Pharmacy, Inorganic Chemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | - Martin Albrecht
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, CH-3012 Bern, Switzerland
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14
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Race JJ, Burnage AL, Boyd TM, Heyam A, Martínez-Martínez AJ, Macgregor SA, Weller AS. Ortho-aryl substituted DPEphos ligands: rhodium complexes featuring C-H anagostic interactions and B-H agostic bonds. Chem Sci 2021; 12:8832-8843. [PMID: 34257884 PMCID: PMC8246285 DOI: 10.1039/d1sc01430g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 05/24/2021] [Indexed: 11/29/2022] Open
Abstract
The synthesis of new Schrock–Osborn Rh(i) pre-catalysts with ortho-substituted DPEphos ligands, [Rh(DPEphos-R)(NBD)][BArF4] [R = Me, OMe, iPr; ArF = 3,5-(CF3)2C6H3], is described. Along with the previously reported R = H variant, variable temperature 1H NMR spectroscopic and single-crystal X-ray diffraction studies show that these all have axial (C–H)⋯Rh anagostic interactions relative to the d8 pseudo square planar metal centres, that also result in corresponding downfield chemical shifts. Analysis by NBO, QTAIM and NCI methods shows these to be only very weak C–H⋯Rh bonding interactions, the magnitudes of which do not correlate with the observed chemical shifts. Instead, as informed by Scherer's approach, it is the topological positioning of the C–H bond with regard to the metal centre that is important. For [Rh(DPEphos–iPr)(NBD)][BArF4] addition of H2 results in a Rh(iii) iPr–C–H activated product, [Rh(κ3,σ-P,O,P-DPEphos-iPr′)(H)][BArF4]. This undergoes H/D exchange with D2 at the iPr groups, reacts with CO or NBD to return Rh(i) products, and reaction with H3B·NMe3/tert-butylethene results in a dehydrogenative borylation to form a complex that shows both a non-classical B–H⋯Rh 3c-2e agostic bond and a C–H⋯Rh anagostic interaction at the same metal centre. Rh(i) complexes of ortho-substituted DPEphos-R (R = H, Me, OMe, iPr) ligands show anagostic interactions; for R =iPr C–H activation/dehydrogenative borylation forms a product exhibiting both B–H/Rh 3c-2e agostic and C–H/Rh anagostic motifs.![]()
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Affiliation(s)
- James J Race
- Department of Chemistry, University of York Heslington York YO10 5DD UK .,Chemistry Research Laboratories, University of Oxford Oxford OX1 3TA UK
| | - Arron L Burnage
- Institute of Chemical Sciences, Heriot Watt University Edinburgh EH14 4AS UK
| | - Timothy M Boyd
- Department of Chemistry, University of York Heslington York YO10 5DD UK .,Chemistry Research Laboratories, University of Oxford Oxford OX1 3TA UK
| | - Alex Heyam
- Chemistry Research Laboratories, University of Oxford Oxford OX1 3TA UK
| | | | - Stuart A Macgregor
- Institute of Chemical Sciences, Heriot Watt University Edinburgh EH14 4AS UK
| | - Andrew S Weller
- Department of Chemistry, University of York Heslington York YO10 5DD UK
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15
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Esteruelas MA, Oñate E, Paz S, Vélez A. Repercussion of a 1,3-Hydrogen Shift in a Hydride-Osmium-Allenylidene Complex. Organometallics 2021; 40:1523-1537. [PMID: 35693112 PMCID: PMC9180373 DOI: 10.1021/acs.organomet.1c00176] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Indexed: 12/16/2022]
Abstract
![]()
An unusual 1,3-hydrogen shift from the metal center to the Cβ atom of the C3-chain of the allenylidene
ligand in a hydride-osmium(II)-allenylidene complex is the beginning
of several interesting transformations in the cumulene. The hydride-osmium(II)-allenylidene
complex was prepared in two steps, starting from the tetrahydride
dimer [(Os(H···H){κ3-P,O,P-[xant(PiPr2)2]})2(μ-Cl)2][BF4]2 (1). Complex 1 reacts with 1,1-diphenyl-2-propyn-1-ol to give the hydride-osmium(II)-alkenylcarbyne
[OsHCl(≡CCH=CPh2){κ3-P,O,P-[xant(PiPr2)2]}]BF4 (2), which yields OsHCl(=C=C=CPh2){κ3-P,O,P-[xant(PiPr2)2]} (3) by selective abstraction of the Cβ–H hydrogen atom of the alkenylcarbyne ligand
with KtBuO. Complex 3 is
metastable. According to results of DFT calculations, the migration
of the hydride ligand to the Cβ atom of the cumulene
has an activation energy too high to occur in a concerted manner.
However, the migration can be catalyzed by water, alcohols, and aldehydes.
The resulting alkenylcarbyne-osmium(0) intermediate is unstable and
evolves into a 7:3 mixture of the hydride-osmium(II)-indenylidene
OsHCl(=CIndPh){κ3-P,O,P-[xant(PiPr2)2]} (4) and the osmanaphthalene
OsCl(C9H6Ph){κ3-P,O,P-[xant(PiPr2)2]} (5). Protonation
of 4 with HBF4 leads to the elongated dihydrogen
complex [OsCl(η2-H2)(=CIndPh){κ3-P,O,P-[xant(PiPr2)2]}]BF4 (6), while the protonation
of 5 regenerates 2. In contrast to 4, complex 6 evolves to a half-sandwich indenyl
derivative, [Os(η5-IndPh)H{κ3-P,O,P-[xant(PiPr2)2]}][BF4]Cl
(7). Phenylacetylene also provokes the 1,3-hydrogen shift
in 3. However, it does not participate in the migration.
In contrast to water, alcohols, and aldehydes, it stabilizes the resulting
alkenylcarbyne to afford [Os(≡CCH=CPh2)(η2-HC≡CPh){κ3-P,O,P-[xant(PiPr2)2]}]Cl (8).
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Affiliation(s)
- Miguel A. Esteruelas
- Departamento de Química Inorgánica − Instituto de Síntesis Química y Catálisis Homogénea (ISQCH) − Centro de Innovación en Química Avanzada (ORFEO−CINCA), Universidad de Zaragoza − CSIC, 50009 Zaragoza, Spain
| | - Enrique Oñate
- Departamento de Química Inorgánica − Instituto de Síntesis Química y Catálisis Homogénea (ISQCH) − Centro de Innovación en Química Avanzada (ORFEO−CINCA), Universidad de Zaragoza − CSIC, 50009 Zaragoza, Spain
| | - Sonia Paz
- Departamento de Química Inorgánica − Instituto de Síntesis Química y Catálisis Homogénea (ISQCH) − Centro de Innovación en Química Avanzada (ORFEO−CINCA), Universidad de Zaragoza − CSIC, 50009 Zaragoza, Spain
| | - Andrea Vélez
- Departamento de Química Inorgánica − Instituto de Síntesis Química y Catálisis Homogénea (ISQCH) − Centro de Innovación en Química Avanzada (ORFEO−CINCA), Universidad de Zaragoza − CSIC, 50009 Zaragoza, Spain
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16
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Devillard M, De Albuquerque Pinheiro CA, Caytan E, Roiland C, Dinoi C, Del Rosal I, Alcaraz G. Uncatalyzed Formation of Polyaminoboranes from Diisopropylaminoborane and Primary Amines: a Kinetically Controlled Polymerization Reaction. Adv Synth Catal 2021. [DOI: 10.1002/adsc.202001458] [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)
- Marc Devillard
- Univ Rennes CNRS ISCR (Institut des Sciences Chimiques de Rennes) 35000 Rennes France
| | | | - Elsa Caytan
- Univ Rennes CNRS ISCR (Institut des Sciences Chimiques de Rennes) 35000 Rennes France
| | - Claire Roiland
- Univ Rennes CNRS ISCR (Institut des Sciences Chimiques de Rennes) 35000 Rennes France
| | - Chiara Dinoi
- LPCNO CNRS & INSA Universitć de Toulouse 135 avenue de Rangueil 31077 Toulouse France
| | - Iker Del Rosal
- LPCNO CNRS & INSA Universitć de Toulouse 135 avenue de Rangueil 31077 Toulouse France
| | - Gilles Alcaraz
- Univ Rennes CNRS ISCR (Institut des Sciences Chimiques de Rennes) 35000 Rennes France
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17
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Lindenau K, Jannsen N, Rippke M, Al Hamwi H, Selle C, Drexler HJ, Spannenberg A, Sawall M, Neymeyr K, Heller D, Reiß F, Beweries T. Mechanistic insights into dehydrocoupling of amine boranes using dinuclear zirconocene complexes. Catal Sci Technol 2021. [DOI: 10.1039/d1cy00531f] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Catalytic dehydrocoupling of H3B·NMe2H using Cp2Zr(Cl)(μ-Me3SiC3SiMe3)Zr(Cl)Cp2 (1)/MeLi was studied. Spectroscopic monitoring and stoichiometric experiments show the formation and interconversion of several catalytically active Zr species.
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Affiliation(s)
| | - Nora Jannsen
- Leibniz-Institut für Katalyse e.V
- 18059 Rostock
- Germany
| | - Mirko Rippke
- Leibniz-Institut für Katalyse e.V
- 18059 Rostock
- Germany
| | | | - Carmen Selle
- Leibniz-Institut für Katalyse e.V
- 18059 Rostock
- Germany
| | | | | | - Mathias Sawall
- Institut für Mathematik
- Universität Rostock
- 18055 Rostock
- Germany
| | - Klaus Neymeyr
- Leibniz-Institut für Katalyse e.V
- 18059 Rostock
- Germany
- Institut für Mathematik
- Universität Rostock
| | - Detlef Heller
- Leibniz-Institut für Katalyse e.V
- 18059 Rostock
- Germany
| | - Fabian Reiß
- Leibniz-Institut für Katalyse e.V
- 18059 Rostock
- Germany
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18
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Hasche P, Haak J, Anke F, Kubis C, Baumann W, Drexler HJ, Jiao H, Beweries T. Dehydropolymerisation of methylamine borane using highly active rhodium(iii) bis(thiophosphinite) pincer complexes: catalytic and mechanistic insights. Catal Sci Technol 2021. [DOI: 10.1039/d1cy00124h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The bis(thiophosphinite) pincer complexes [(RPSCSPR)Rh(py)(H)(Cl)] (RPSCSPR = C6H4–2,6-(SPR2)2 with R = iPr, 2a and R = Ph, 2b) are highly active precatalysts for the dehydropolymerisation of methylamine borane.
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Affiliation(s)
- Patrick Hasche
- Leibniz-Institut für Katalyse e.V. (LIKAT)
- 18059 Rostock
- Germany
| | - Julia Haak
- Leibniz-Institut für Katalyse e.V. (LIKAT)
- 18059 Rostock
- Germany
| | - Felix Anke
- Leibniz-Institut für Katalyse e.V. (LIKAT)
- 18059 Rostock
- Germany
| | - Christoph Kubis
- Leibniz-Institut für Katalyse e.V. (LIKAT)
- 18059 Rostock
- Germany
| | | | | | - Haijun Jiao
- Leibniz-Institut für Katalyse e.V. (LIKAT)
- 18059 Rostock
- Germany
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