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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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Herbert DE, Gilroy JB, Staubitz A, Haddow MF, Harvey JN, Manners I. Strain-Induced Cleavage of Carbon−Carbon Bonds: Bridge Rupture Reactions of Group 8 Dicarba[2]metallocenophanes. J Am Chem Soc 2010; 132:1988-98. [DOI: 10.1021/ja9087049] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- David E. Herbert
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, United Kingdom
| | - Joe B. Gilroy
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, United Kingdom
| | - Anne Staubitz
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, United Kingdom
| | - Mairi F. Haddow
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, United Kingdom
| | - Jeremy N. Harvey
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, United Kingdom
| | - Ian Manners
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, United Kingdom
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Estephane J, Groppo E, Vitillo JG, Damin A, Lamberti C, Bordiga S, Zecchina A. Chromocene in porous polystyrene: an example of organometallic chemistry in confined spaces. Phys Chem Chem Phys 2009; 11:2218-27. [DOI: 10.1039/b814109f] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Herrmann C, Kehr G, Fröhlich R, Erker G. Chemical Behavior of a Pair of (COD)CpRh and −Ir Complexes with Pendant Peripheral −B(C6F5)2 Groups. Organometallics 2008. [DOI: 10.1021/om800195d] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christoph Herrmann
- Organisch-Chemisches Institut der Universität Münster, Corrensstrasse 40, 48149 Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut der Universität Münster, Corrensstrasse 40, 48149 Münster, Germany
| | - Roland Fröhlich
- Organisch-Chemisches Institut der Universität Münster, Corrensstrasse 40, 48149 Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut der Universität Münster, Corrensstrasse 40, 48149 Münster, Germany
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Ieong N, Chan W, Lough A, Haddow M, Manners I. Photoinduced FeCp Bond Cleavage and Insertion Reactions of Strained Silicon- and Sulphur-Bridged [1]Ferrocenophanes in the Presence of Transition-Metal Carbonyls. Chemistry 2008; 14:1253-63. [DOI: 10.1002/chem.200700961] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Herbert DE, Mayer UFJ, Manners I. Strained metallocenophanes and related organometallic rings containing pi-hydrocarbon ligands and transition-metal centers. Angew Chem Int Ed Engl 2007; 46:5060-81. [PMID: 17587203 DOI: 10.1002/anie.200604409] [Citation(s) in RCA: 211] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The structures, bonding, and ring-opening reactions of strained cyclic carbon-based molecules form a key component of standard textbooks. In contrast, the study of strained organometallic molecules containing transition metals is a much more recent development. A wealth of recent research has revealed fascinating nuances in terms of structure, bonding, and reactivity. Building on initial work on strained ferrocenophanes, a broad range of strained organometallic rings composed of a variety of different metals, pi-hydrocarbon ligands, and bridging elements has now been developed. Such strained species can potentially undergo ring-opening reactions to functionalize surfaces and ring-opening polymerization to form easily processed metallopolymers with properties determined by the presence of the metal and spacer. This Review summarizes the current state of knowledge on the preparation, structural characterization, electronic structure, and reactivity of strained organometallic rings with pi-hydrocarbon ligands and d-block metals.
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Affiliation(s)
- David E Herbert
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS81TS, UK
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Shapiro PJ, Sinnema PJ, Perrotin P, Budzelaar PHM, Weihe H, Twamley B, Zehnder RA, Nairn JJ. Ring-Borylated 15-Electron and 17-Electronansa-Chromocene Complexes, their Physical Properties and Molecular Structures. Chemistry 2007; 13:6212-22. [PMID: 17506047 DOI: 10.1002/chem.200601901] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A detailed study of the thermal decomposition of the zwitterionic, ring-borylated ansa-chromocene hydrido carbonyl complex [Cr(CO)H{Me(4)C(2)(C(5)H(4))[C(5)H(3)B(C(6)F(5))(3)]}] (2) is described. This complex is formed in the reaction between [Cr(CO){Me(4)C(2)(C(5)H(4))(2)}] (1) and B(C(6)F(5))(3) in toluene at -78 degrees C. Above -25 degrees C, 2 decomposes to a 50:50 mixture of the low-spin, 17e Cr(III) complexes [Cr(CO){Me(4)C(2)(C(5)H(4))[C(5)H(3)B(C(6)F(5))(3)]}] (3b) and [Cr(CO){Me(4)C(2)(C(5)H(4))(2)}][HB(C(6)F(5))(3)] (4). Carbon monoxide elimination from 3 b generates high-spin, 15 e [Cr{Me(4)C(2)(C(5)H(4))[C(5)H(3)B(C(6)F(5))(3)]}] (3a), which coordinates two other electron-donating ligands, such as xylyl isocyanide, PMe3, and PPh(2)Me to form the low-spin, 17 e electron complexes 3c, 3d, and 3e, respectively. High-spin, 15 e [Cr{Me(4)C(2)(C(5)H(4))(2)}][HB(C(6)F(5))(3)] (5) is generated by heating 3 b in toluene at 100 degrees C and periodically removing the evolved CO. Efforts to isolate more than a few X-ray quality crystals of 5 were thwarted by its tendency to form an insoluble precipitate (6) with the same molecular formula. Heating the solution of 5 at 120 degrees C results in its partial conversion (ca. 28 %) to 3a, thereby allowing the formation of 3a in yields as high as 74 % from the reaction between 1 and B(C(6)F(5))(3). The X-ray crystal structures of 3 b-e and 5 are described. Cyclic voltammetry measurements on 3 a-e reveal a dramatic reduction in the redox potentials of the complexes relative to their non-borylated analogues. DFT calculations show that this is due primarily to electrostatic stabilization of the oxidized species by the negatively charged borylate group. EPR and 19F NMR spectroscopy allow 3a to be distinguished from its Lewis base adducts 3 b-e and reveal the relative affinities of different Lewis bases for the chromium.
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Affiliation(s)
- Pamela J Shapiro
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, USA.
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Herbert D, Mayer U, Manners I. Gespannte Metallocenophane und ähnliche metallorganische Ringe mit π-Kohlenwasserstoffliganden und Übergangsmetallzentren. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200604409] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Perrotin P, Shapiro PJ, Williams M, Twamley B. In Search of a Versatile Pathway to ansa-Chromocene Complexes. Synthesis and Characterization of the Highly Unstable ansa-Chromocene Carbonyl Complex Me2C(C5H4)2CrCO. Organometallics 2007. [DOI: 10.1021/om061136u] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Philippe Perrotin
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343
| | - Pamela J. Shapiro
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343
| | - Mark Williams
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343
| | - Brendan Twamley
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343
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Schaper F, Wrobel O, Schwörer R, Brintzinger HH. Me2Si(C5Me4)2Cr: Synthesis and Crystal Structure of a Ligand-Free ansa-Chromocene. Organometallics 2004. [DOI: 10.1021/om049901x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Frank Schaper
- Department of Chemistry, University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland, and Fachbereich Chemie, Universität Konstanz, D-78457 Konstanz, Germany
| | - Olaf Wrobel
- Department of Chemistry, University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland, and Fachbereich Chemie, Universität Konstanz, D-78457 Konstanz, Germany
| | - Ralf Schwörer
- Department of Chemistry, University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland, and Fachbereich Chemie, Universität Konstanz, D-78457 Konstanz, Germany
| | - Hans-Herbert Brintzinger
- Department of Chemistry, University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland, and Fachbereich Chemie, Universität Konstanz, D-78457 Konstanz, Germany
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