1
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Ashuiev A, Allouche F, Islam MA, Carvalho JP, Sanders KJ, Conley MP, Klose D, Lapadula G, Wörle M, Baabe D, Walter MD, Pell AJ, Copéret C, Jeschke G, Pintacuda G, Andersen RA. Geometry and electronic structure of Yb(III)[CH(SiMe 3) 2] 3 from EPR and solid-state NMR augmented by computations. Phys Chem Chem Phys 2024; 26:8734-8747. [PMID: 38416412 PMCID: PMC10936694 DOI: 10.1039/d4cp00281d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 02/12/2024] [Indexed: 02/29/2024]
Abstract
Characterization of paramagnetic compounds, in particular regarding the detailed conformation and electronic structure, remains a challenge, and - still today it often relies solely on the use of X-ray crystallography, thus limiting the access to electronic structure information. This is particularly true for lanthanide elements that are often associated with peculiar structural and electronic features in relation to their partially filled f-shell. Here, we develop a methodology based on the combined use of state-of-the-art magnetic resonance spectroscopies (EPR and solid-state NMR) and computational approaches as well as magnetic susceptibility measurements to determine the electronic structure and geometry of a paramagnetic Yb(III) alkyl complex, Yb(III)[CH(SiMe3)2]3, a prototypical example, which contains notable structural features according to X-ray crystallography. Each of these techniques revealed specific information about the geometry and electronic structure of the complex. Taken together, both EPR and NMR, augmented by quantum chemical calculations, provide a detailed and complementary understanding of such paramagnetic compounds. In particular, the EPR and NMR signatures point to the presence of three-centre-two-electron Yb-γ-Me-β-Si secondary metal-ligand interactions in this otherwise tri-coordinate metal complex, similarly to its diamagnetic Lu analogues. The electronic structure of Yb(III) can be described as a single 4f13 configuration, while an unusually large crystal-field splitting results in a thermally isolated ground Kramers doublet. Furthermore, the computational data indicate that the Yb-carbon bond contains some π-character, reminiscent of the so-called α-H agostic interaction.
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Affiliation(s)
- Anton Ashuiev
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5, 8093 Zurich, Switzerland.
| | - Florian Allouche
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5, 8093 Zurich, Switzerland.
| | - Md Ashraful Islam
- Université de Lyon, Centre de RMN à Très Hauts Champs de Lyon (UMR 5082 - CNRS, ENS Lyon, Université Claude Bernard Lyon 1), F-69100 Villeurbanne, France.
| | - José P Carvalho
- Department of Materials and Environmental Chemistry, Stockholm University, Svänte Arrhenius väg 16 C, 106 91 Stockholm, Sweden
| | - Kevin J Sanders
- Université de Lyon, Centre de RMN à Très Hauts Champs de Lyon (UMR 5082 - CNRS, ENS Lyon, Université Claude Bernard Lyon 1), F-69100 Villeurbanne, France.
| | - Matthew P Conley
- Department of Chemistry and Chemical Sciences, University of California Riverside, 501 Big Springs Road, Riverside, CA 92521, USA
| | - Daniel Klose
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5, 8093 Zurich, Switzerland.
| | - Giuseppe Lapadula
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5, 8093 Zurich, Switzerland.
| | - Michael Wörle
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5, 8093 Zurich, Switzerland.
| | - Dirk Baabe
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Marc D Walter
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Andrew J Pell
- Université de Lyon, Centre de RMN à Très Hauts Champs de Lyon (UMR 5082 - CNRS, ENS Lyon, Université Claude Bernard Lyon 1), F-69100 Villeurbanne, France.
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5, 8093 Zurich, Switzerland.
| | - Gunnar Jeschke
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5, 8093 Zurich, Switzerland.
| | - Guido Pintacuda
- Université de Lyon, Centre de RMN à Très Hauts Champs de Lyon (UMR 5082 - CNRS, ENS Lyon, Université Claude Bernard Lyon 1), F-69100 Villeurbanne, France.
| | - Richard A Andersen
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
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2
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Pobłocki K, Jarzembska KN, Kamiński R, Drzeżdżon J, Deresz KA, Schaniel D, Gołąbiewska A, Gawdzik B, Rybiński P, Jacewicz D. Porous oligomeric materials synthesised using a new, highly active precatalyst based on ruthenium(III) and 2-phenylpyridine. Dalton Trans 2024; 53:4194-4203. [PMID: 38323842 DOI: 10.1039/d3dt04091g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
There are few literature reports on using precatalysts based on ruthenium(II/III) ions in the polymerization of olefins. Therefore, a new coordination compound was designed based on ruthenium(III) ion and 2-phenylpyridine. The resulting monocrystal was characterized by X-ray diffraction (XRD), solid-state (photo)IR spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The new ruthenium(III) complex compound was used as a precatalyst in the oligomerization reactions of ethylene, 2-propen-1-ol, 2-chloro-2-propen-1-ol, 3-butene-2-ol and 2,3-dibromo-2-propen-1-ol with methylaluminoxane and ethylaluminium dichloride as activators. The catalytic activity of the newly discovered ruthenium(III) complex compound ranges from 159.5 (for 2-chloro-2-propen-1-ol) to 755.6 (for ethylene) g mmol-1 h-1 bar-1, indicating that it is a chemical compound with high catalytic activity. In addition, the oligomerization reaction products were subjected to physicochemical characterization, using BET (Brunauer-Emmett-Teller isotherm), mass spectrometry (MALDI-TOF-MS), Fourier transform infrared (FT-IR) spectroscopy, NMR, TGA, differential scanning calorimetry (DSC), and the morphology of the porous polymeric materials was investigated by SEM. The distinguishing feature of the obtained precatalyst is its high catalytic activity under mild reaction conditions, a rare phenomenon. Compared with other precatalysts, it is the most active ruthenium(II/III) ion-based catalytic material used in oligo- and polymerization reactions of ethylene.
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Affiliation(s)
- Kacper Pobłocki
- Department of Environmental Technology, Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland.
| | - Katarzyna N Jarzembska
- Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Radosław Kamiński
- Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Joanna Drzeżdżon
- Department of Environmental Technology, Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland.
| | - Krystyna A Deresz
- Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | | | - Anna Gołąbiewska
- Department of Environmental Technology, Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland.
| | - Barbara Gawdzik
- Institute of Chemistry, Jan Kochanowski University, Uniwersytecka 7, 25-406 Kielce, Poland
| | - Przemysław Rybiński
- Institute of Chemistry, Jan Kochanowski University, Uniwersytecka 7, 25-406 Kielce, Poland
| | - Dagmara Jacewicz
- Department of Environmental Technology, Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, 80-308 Gdansk, Poland.
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3
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Ashuiev A, Giorgia Nobile A, Trummer D, Klose D, Guda S, Safonova OV, Copéret C, Guda A, Jeschke G. Active Sites in Cr(III)-Based Ethylene Polymerization Catalysts from Machine-Learning-Supported XAS and EPR Spectroscopy. Angew Chem Int Ed Engl 2024; 63:e202313348. [PMID: 37970660 DOI: 10.1002/anie.202313348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/13/2023] [Accepted: 11/16/2023] [Indexed: 11/17/2023]
Abstract
The ethylene polymerization Phillips catalyst has been employed for decades and is central to the polymer industry. While Cr(III) alkyl species are proposed to be the propagating sites, there is so far no direct experimental evidence for such proposal. In this work, by coupling Surface organometallic chemistry, EPR spectroscopy, and machine learning-supported XAS studies, we have studied the electronic structure of well-defined silica-supported Cr(III) alkyls and identified the presence of several surface species in high and low-spin states, associated with different coordination environments. Notably, low-spin Cr(III) sites are shown to participate in ethylene polymerization, indicating that similar Cr(III) alkyl species could be involved in the related Phillips catalyst.
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Affiliation(s)
- Anton Ashuiev
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, 8093, Zürich, Switzerland
| | - Anna Giorgia Nobile
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, 8093, Zürich, Switzerland
| | - David Trummer
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, 8093, Zürich, Switzerland
| | - Daniel Klose
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, 8093, Zürich, Switzerland
| | - Sergey Guda
- The Smart Materials Research Institute, Southern Federal University, Sladkova 178/24, Rostov-on-Don, 344090, Russia
| | - Olga V Safonova
- Paul Scherrer Institut, WLGA/217, Forschungsstrasse 111, 5232, Villigen PSI, Switzerland
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, 8093, Zürich, Switzerland
| | - Alexander Guda
- The Smart Materials Research Institute, Southern Federal University, Sladkova 178/24, Rostov-on-Don, 344090, Russia
| | - Gunnar Jeschke
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, 8093, Zürich, Switzerland
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4
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Nifant’ev IE, Komarov PD, Kostomarova OD, Kolosov NA, Ivchenko PV. MAO- and Borate-Free Activating Supports for Group 4 Metallocene and Post-Metallocene Catalysts of α-Olefin Polymerization and Oligomerization. Polymers (Basel) 2023; 15:3095. [PMID: 37514483 PMCID: PMC10384419 DOI: 10.3390/polym15143095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/15/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023] Open
Abstract
Modern industry of advanced polyolefins extensively uses Group 4 metallocene and post-metallocene catalysts. High-throughput polyolefin technologies demand the use of heterogeneous catalysts with a given particle size and morphology, high thermal stability, and controlled productivity. Conventional Group 4 metal single-site heterogeneous catalysts require the use of high-cost methylalumoxane (MAO) or perfluoroaryl borate activators. However, a number of inorganic phases, containing highly acidic Lewis and Brønsted sites, are able to activate Group 4 metal pre-catalysts using low-cost and affordable alkylaluminums. In the present review, we gathered comprehensive information on MAO- and borate-free activating supports of different types and discussed the surface nature and chemistry of these phases, examples of their use in the polymerization of ethylene and α-olefins, and prospects of the further development for applications in the polyolefin industry.
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Affiliation(s)
- Ilya E. Nifant’ev
- A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Leninsky Av. 29, 119991 Moscow, Russia; (I.E.N.); (P.D.K.)
- Chemistry Department, M.V. Lomonosov Moscow State University, Leninskie Gory 1-3, 119991 Moscow, Russia
| | - Pavel D. Komarov
- A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Leninsky Av. 29, 119991 Moscow, Russia; (I.E.N.); (P.D.K.)
| | | | - Nikolay A. Kolosov
- NIOST LLC, Kuzovlevsky Tr. 2-270, 634067 Tomsk, Russia; (O.D.K.); (N.A.K.)
| | - Pavel V. Ivchenko
- A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Leninsky Av. 29, 119991 Moscow, Russia; (I.E.N.); (P.D.K.)
- Chemistry Department, M.V. Lomonosov Moscow State University, Leninskie Gory 1-3, 119991 Moscow, Russia
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5
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Nobile AG, Trummer D, Berkson ZJ, Wörle M, Copéret C, Payard PA. Assigning 1H chemical shifts in paramagnetic mono- and bimetallic surface sites using DFT: a case study on the Union Carbide polymerization catalyst. Chem Sci 2023; 14:2361-2368. [PMID: 36873845 PMCID: PMC9977395 DOI: 10.1039/d2sc06827c] [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: 12/11/2022] [Accepted: 01/27/2023] [Indexed: 02/05/2023] Open
Abstract
The Union Carbide (UC) ethylene polymerization catalyst, based on silica-supported chromocene, is one of the first industrial catalysts prepared by surface organometallic chemistry, though the structure of the surface sites remains elusive. Recently, our group reported that monomeric and dimeric Cr(ii) sites, as well as Cr(iii) hydride sites, are present and that their proportion varies as a function of the Cr loading. While 1H chemical shifts extracted from solid-state 1H NMR spectra should be diagnostic of the structure of such surface sites, unpaired electrons centered on Cr atoms induce large paramagnetic 1H shifts that complicate their NMR analysis. Here, we implement a cost-efficient DFT methodology to calculate 1H chemical shifts for antiferromagnetically coupled metal dimeric sites using a Boltzmann-averaged Fermi contact term over the population of the different spin states. This method allowed us to assign the 1H chemical shifts observed for the industrial-like UC catalyst. The presence of monomeric and dimeric Cr(ii) sites, as well as a dimeric Cr(iii)-hydride sites, was confirmed and their structure was clarified.
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Affiliation(s)
- Anna Giorgia Nobile
- ETH Zürich Department of Chemistry and Applied Biosciences Vladimir-Prelog-Weg 2 CH-8093 Zürich Switzerland
| | - David Trummer
- ETH Zürich Department of Chemistry and Applied Biosciences Vladimir-Prelog-Weg 2 CH-8093 Zürich Switzerland
| | - Zachariah J Berkson
- ETH Zürich Department of Chemistry and Applied Biosciences Vladimir-Prelog-Weg 2 CH-8093 Zürich Switzerland
| | - Michael Wörle
- ETH Zürich Department of Chemistry and Applied Biosciences Vladimir-Prelog-Weg 2 CH-8093 Zürich Switzerland
| | - Christophe Copéret
- ETH Zürich Department of Chemistry and Applied Biosciences Vladimir-Prelog-Weg 2 CH-8093 Zürich Switzerland
| | - Pierre-Adrien Payard
- ETH Zürich Department of Chemistry and Applied Biosciences Vladimir-Prelog-Weg 2 CH-8093 Zürich Switzerland .,Université de Lyon, Université Claude Bernard Lyon I, CNRS, INSA, CPE, UMR 5246, ICBMS Rue Victor Grignard F-69622 Villeurbanne Cedex France
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6
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Scarpi-Luttenauer M, Mobian P, Barloy L. Synthesis, structure and functions of discrete titanium-based multinuclear architectures. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214439] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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7
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Trummer D, Nobile AG, Payard PA, Ashuiev A, Kakiuchi Y, Klose D, Jeschke G, Copéret C. Union carbide polymerization catalysts: from uncovering active site structures to designing molecularly-defined analogs. Chem Sci 2022; 13:11091-11098. [PMID: 36320461 PMCID: PMC9517275 DOI: 10.1039/d2sc04235e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 09/01/2022] [Indexed: 11/21/2022] Open
Abstract
The Union Carbide (UC) ethylene polymerization catalysts, based on chromocene dispersed on silica, show distinct features from the Phillips catalysts, but share the same heated debate regarding the structure of their active sites. Based on a combination of IR, EPR spectroscopies, labeling experiments, and DFT modeling, we identified monomeric surface-supported Cr(iii) hydrides, (
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SiO)Cr(Cp)–H, as the active sites of the UC catalyst. These sites are formed in the presence of grafted and adsorbed chromocene as well as residual surface OH groups, only possible at high Cr loading, and involve a C–H activation of the Cp ring. These Cr-hydrides initiate polymerization, yielding Cr(iii) alkyl species that insert ethylene through a Cossee–Arlman-type mechanism, as evidenced by spectroscopic studies. These insights inspired the design of a well-defined analog, CpCr(CH(SiMe3)2)2 grafted on partially dehydroxylated silica, that shows similar spectroscopic and polymer structure to the UC catalyst, further supporting the proposed active site structure. A combined SOMC and DFT studies on the Union Carbide catalyst enable to propose that Cr(iii)-H, formed at high-loading, are active in ethylene polymerization. We therefore design a well-defined supported CpCr(iii)-R ethylene polymerization catalyst.![]()
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Affiliation(s)
- David Trummer
- ETH Zürich Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, Zürich CH-8093, Switzerland
| | - Anna Giorgia Nobile
- ETH Zürich Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, Zürich CH-8093, Switzerland
| | - Pierre-Adrien Payard
- ETH Zürich Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, Zürich CH-8093, Switzerland
| | - Anton Ashuiev
- ETH Zürich Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, Zürich CH-8093, Switzerland
| | - Yuya Kakiuchi
- ETH Zürich Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, Zürich CH-8093, Switzerland
| | - Daniel Klose
- ETH Zürich Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, Zürich CH-8093, Switzerland
| | - Gunnar Jeschke
- ETH Zürich Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, Zürich CH-8093, Switzerland
| | - Christophe Copéret
- ETH Zürich Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg 2, Zürich CH-8093, Switzerland
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8
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Kehl A, Hiller M, Hecker F, Tkach I, Dechert S, Bennati M, Meyer A. Resolution of chemical shift anisotropy in 19F ENDOR spectroscopy at 263 GHz/9.4 T. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 333:107091. [PMID: 34749036 DOI: 10.1016/j.jmr.2021.107091] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 06/13/2023]
Abstract
Pulsed 19F ENDOR spectroscopy provides a selective method for measuring angstrom to nanometer distances in structural biology. Here, the performance of 19F ENDOR at fields of 3.4 T and 9.4 T is compared using model compounds containing one to three 19F atoms. CF3 groups are included in two compounds, for which the possible occurrence of uniaxial rotation might affect the distance distribution. At 9.4 T, pronounced asymmetric features are observed in many of the presented 19F ENDOR spectra. Data analysis by spectral simulations shows that these features arise from the chemical shift anisotropy (CSA) of the 19F nuclei. This asymmetry is also observed at 3.4 T, albeit to a much smaller extent, confirming the physical origin of the effect. The CSA parameters are well consistent with DFT predicted values and can be extracted from simulation of the experimental data in favourable cases, thereby providing additional information about the geometrical and electronic structure of the spin system. The feasibility of resolving the CSA at 9.4 T provides important information for the interpretation of line broadening in ENDOR spectra also at lower fields, which is relevant for developing methods to extract distance distributions from 19F ENDOR spectra.
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Affiliation(s)
- Annemarie Kehl
- Research Group EPR Spectroscopy, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Markus Hiller
- Research Group EPR Spectroscopy, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Fabian Hecker
- Research Group EPR Spectroscopy, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Igor Tkach
- Research Group EPR Spectroscopy, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Sebastian Dechert
- Department of Chemistry, Georg August University of Göttingen, Tammannstr. 4, Göttingen, Germany
| | - Marina Bennati
- Research Group EPR Spectroscopy, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany; Department of Chemistry, Georg August University of Göttingen, Tammannstr. 4, Göttingen, Germany.
| | - Andreas Meyer
- Research Group EPR Spectroscopy, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
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10
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Piovano A, Signorile M, Braglia L, Torelli P, Martini A, Wada T, Takasao G, Taniike T, Groppo E. Electronic Properties of Ti Sites in Ziegler–Natta Catalysts. ACS Catal 2021. [DOI: 10.1021/acscatal.1c01735] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alessandro Piovano
- Department of Chemistry, INSTM and NIS Centre, University of Torino, Via Giuria 7, 10125 Torino, Italy
- DPI, P.O.
Box 902, 5600 AX Eindhoven, The Netherlands
| | - Matteo Signorile
- Department of Chemistry, INSTM and NIS Centre, University of Torino, Via Giuria 7, 10125 Torino, Italy
| | | | | | - Andrea Martini
- Department of Chemistry, INSTM and NIS Centre, University of Torino, Via Giuria 7, 10125 Torino, Italy
- The Smart Materials Research Institute, Southern Federal University, Sladkova 178/24, 344090 Rostov-on-Don, Russia
| | - Toru Wada
- DPI, P.O.
Box 902, 5600 AX Eindhoven, The Netherlands
- Graduate School of Advanced Science and Technology, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
| | - Gentoku Takasao
- Graduate School of Advanced Science and Technology, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
| | - Toshiaki Taniike
- DPI, P.O.
Box 902, 5600 AX Eindhoven, The Netherlands
- Graduate School of Advanced Science and Technology, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
| | - Elena Groppo
- Department of Chemistry, INSTM and NIS Centre, University of Torino, Via Giuria 7, 10125 Torino, Italy
- DPI, P.O.
Box 902, 5600 AX Eindhoven, The Netherlands
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11
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Ashuiev A, Humbert M, Norsic S, Blahut J, Gajan D, Searles K, Klose D, Lesage A, Pintacuda G, Raynaud J, Monteil V, Copéret C, Jeschke G. Spectroscopic Signature and Structure of the Active Sites in Ziegler-Natta Polymerization Catalysts Revealed by Electron Paramagnetic Resonance. J Am Chem Soc 2021; 143:9791-9797. [PMID: 34169715 DOI: 10.1021/jacs.1c02818] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Despite decades of extensive studies, the atomic-scale structure of the active sites in heterogeneous Ziegler-Natta (ZN) catalysts, one of the most important processes of the chemical industry, remains elusive and a matter of debate. In the present work, the structure of active sites of ZN catalysts in the absence of ethylene, referred to as dormant active sites, is elucidated from magnetic resonance experiments carried out on samples reacted with increasing amounts of BCl3 so as to enhance the concentration of active sites and observe clear spectroscopic signatures. Using electron paramagnetic resonance (EPR) and NMR spectroscopies, in particular 2D HYSCORE experiments complemented by density functional theory (DFT) calculations, we show that the activated ZN catalysts contain bimetallic alkyl-Ti(III),Al species whose amount is directly linked to the polymerization activity of MgCl2-supported Ziegler-Natta catalysts. This connects those spectroscopic signatures to the active species formed in the presence of ethylene and enables us to propose an ethylene polymerization mechanism on the observed bimetallic alkyl-Ti(III),Al species based on DFT computations.
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Affiliation(s)
- Anton Ashuiev
- Department of Chemistry and Applied Biosciences, ETH Zurich, Wolfgang-Pauli-Strasse 1-5, 8093 Zurich, Switzerland
| | - Matthieu Humbert
- Université de Lyon, CNRS, Université Lyon 1, CPE Lyon, UMR 5128 - CP2M (Catalysis, Polymerization, Processes & Materials), PolyCatMat team, 43 Bd du 11 Novembre 1918, 69616 Villeurbanne, France
| | - Sébastien Norsic
- Université de Lyon, CNRS, Université Lyon 1, CPE Lyon, UMR 5128 - CP2M (Catalysis, Polymerization, Processes & Materials), PolyCatMat team, 43 Bd du 11 Novembre 1918, 69616 Villeurbanne, France
| | - Jan Blahut
- University of Lyon, High-Field NMR Center (UMR 5082 CNRS/ENS Lyon/Université Claude Bernard Lyon 1), 5 rue de la Doua, 69100 Villeurbanne, France
| | - David Gajan
- University of Lyon, High-Field NMR Center (UMR 5082 CNRS/ENS Lyon/Université Claude Bernard Lyon 1), 5 rue de la Doua, 69100 Villeurbanne, France
| | - Keith Searles
- Department of Chemistry and Applied Biosciences, ETH Zurich, Wolfgang-Pauli-Strasse 1-5, 8093 Zurich, Switzerland
| | - Daniel Klose
- Department of Chemistry and Applied Biosciences, ETH Zurich, Wolfgang-Pauli-Strasse 1-5, 8093 Zurich, Switzerland
| | - Anne Lesage
- University of Lyon, High-Field NMR Center (UMR 5082 CNRS/ENS Lyon/Université Claude Bernard Lyon 1), 5 rue de la Doua, 69100 Villeurbanne, France
| | - Guido Pintacuda
- University of Lyon, High-Field NMR Center (UMR 5082 CNRS/ENS Lyon/Université Claude Bernard Lyon 1), 5 rue de la Doua, 69100 Villeurbanne, France
| | - Jean Raynaud
- Université de Lyon, CNRS, Université Lyon 1, CPE Lyon, UMR 5128 - CP2M (Catalysis, Polymerization, Processes & Materials), PolyCatMat team, 43 Bd du 11 Novembre 1918, 69616 Villeurbanne, France
| | - Vincent Monteil
- Université de Lyon, CNRS, Université Lyon 1, CPE Lyon, UMR 5128 - CP2M (Catalysis, Polymerization, Processes & Materials), PolyCatMat team, 43 Bd du 11 Novembre 1918, 69616 Villeurbanne, France
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences, ETH Zurich, Wolfgang-Pauli-Strasse 1-5, 8093 Zurich, Switzerland
| | - Gunnar Jeschke
- Department of Chemistry and Applied Biosciences, ETH Zurich, Wolfgang-Pauli-Strasse 1-5, 8093 Zurich, Switzerland
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Chiesa M, Giamello E. On the Role and Applications of Electron Magnetic Resonance Techniques in Surface Chemistry and Heterogeneous Catalysis. Catal Letters 2021. [DOI: 10.1007/s10562-021-03576-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Abstract
Some relevant aspects of Electron Paramagnetic Resonance (EPR) applied to the fields of surface chemistry and heterogeneous catalysis are illustrated in this perspective paper that aims to show the potential of these techniques in describing critical features of surface structures and reactivity. Selected examples are employed covering distinct aspects of catalytic science from morphological analysis of surfaces to detailed descriptions of chemical bonding and catalytic sites topology. In conclusions the pros and cons related to the acquisition of EPR instrumentations in an advanced laboratory of surface chemistry and heterogeneous catalysis are briefly considered.
Graphic Abstract
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