1
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Collins S, Linnolahti M. Cages versus Sheets: A Critical Comparison in the Size Range Expected for Methylaluminoxane (MAO). Chemphyschem 2023; 24:e202300342. [PMID: 37314040 DOI: 10.1002/cphc.202300342] [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: 05/10/2023] [Revised: 06/14/2023] [Accepted: 06/14/2023] [Indexed: 06/15/2023]
Abstract
New cage models (MeAlO)n (Me3 Al)m (n=16, m=6 or 7) isomeric with previously reported sheet models for the principle activator found in hydrolytic MAO (h-MAO) are compared at M06-2X and MN15 levels of theory using density functional theory with respect to their thermodynamic stability. Reactivity of the neutrals or corresponding anions with formula [(MeAlO)16 (Me3 Al)6 Me]- towards chlorination, and loss of Me3 Al is explored while reactivity of the neutrals towards formation of contact- and outer-sphere ion pairs from Cp2 ZrMe2 and Cp2 ZrMeCl is examined. The results suggest on balance that a cage model for this activator is less consistent with experiment than an isomeric sheet model, although the latter are more stable based on free energy.
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Affiliation(s)
- Scott Collins
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, Yliopistokatu 7, 80100, Joensuu, Finland
| | - Mikko Linnolahti
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, Yliopistokatu 7, 80100, Joensuu, Finland
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2
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Tanaka R, Sogo K, Komaguchi K, Ae K, Nakayama Y, Shiono T. Impact of Methylaluminoxane Oxidation on Ethylene Polymerization Using Ni Catalysts. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ryo Tanaka
- Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan
| | - Kenji Sogo
- Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan
| | - Kenji Komaguchi
- Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan
| | - Kazuki Ae
- Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan
| | - Yuushou Nakayama
- Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan
| | - Takeshi Shiono
- Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan
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3
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Linnolahti M, Collins S. Thermodynamics of metallocene catalyst activation: alignment of theory and experiment. Dalton Trans 2022; 51:11152-11162. [PMID: 35801522 DOI: 10.1039/d2dt01711c] [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
Three equilibria involved in metallocene catalyst activation, including dissociation of R6Al2 (R = Me, Et or i-Bu) and related species such as [L2ZrMe2AlMe2][B(C6F5)4] (L2 = Cp2, 1,2-ethylenebis(η5-indenyl), Me2C(η5-C5H4)2) or [(L2ZrMe)2μ-Me][MePBB] (L2 = (h5-1,2-Me2C5H3)2, [MePBB]- = [MeB(ArF)3]- with ArF = o-C6F5-C6F4) are studied by DFT using various approaches to account for the enthalpy and entropy changes in gas and condensed phases. These studies reveal that both low energy vibrations and translational entropy conspire to cause significant deviations between theory and experiment when it comes to the free energy change in condensed or even gas phase. Alignment of theory with experiment requires in addition, consideration of specific solvation of reactants and products.
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Affiliation(s)
- Mikko Linnolahti
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, Yliopistokatu 7, FI-80100, Joensuu, Finland.
| | - Scott Collins
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, Yliopistokatu 7, FI-80100, Joensuu, Finland.
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4
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Tran D, Zhang C, Choi KY. Effects of Silica Support Properties on the Performance of Immobilized Metallocene Catalysts for Ethylene Polymerization. MACROMOL REACT ENG 2022. [DOI: 10.1002/mren.202200020] [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)
- Dennis Tran
- Department of Chemical and Biomolecular Engineering University of Maryland College Park Maryland 20742 USA
| | - Chen Zhang
- Department of Chemical and Biomolecular Engineering University of Maryland College Park Maryland 20742 USA
| | - Kyu Yong Choi
- Department of Chemical and Biomolecular Engineering University of Maryland College Park Maryland 20742 USA
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5
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Zhang M, Feng Y, Lou L, Zhang H, Wang J, Yang Y. Flow Toolkit for Measuring Reaction Enthalpy and Application to Highly Exothermic Synthesis of Alkylaluminoxanes. Org Process Res Dev 2022. [DOI: 10.1021/acs.oprd.2c00072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mengbo Zhang
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Yirong Feng
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Linjin Lou
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Haomiao Zhang
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Jingdai Wang
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Yongrong Yang
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P. R. China
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6
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Transition Metal-Catalyzed and MAO-Assisted Olefin Polymerization; Cyclic Isomers of Sinn’s Dimer Are Excellent Ligands in Iron Complexes and Great Methylating Reagents. Catalysts 2022. [DOI: 10.3390/catal12030312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Methylaluminoxane (MAO) is the most commonly used co-catalyst for transition metal-catalyzed olefin polymerization, but the structures of MAO species and their catalytic functions remain topics of intensive study. We are interested in MAO-assisted polymerization with catalysts L(R2)FeCl2 (L = tridentate pyridine-2,6-diyldimethanimine; imine-R = Me, Ph). It is our hypothesis that the MAO species is not merely enabling Fe–Me bond formation but functions as an integral part of the active catalyst, a MAO adduct of the Fe-precatalyst [L(R2)FeCl]+. In this paper, we explored the possible structures of acyclic and cyclic MAO species and their complexation with pre-catalysts [L(R2)FeCl]+ using quantum chemical approaches (MP2 and DFT). We report absolute and relative oxophilicities associated with the Fe ← O(MAO) adduct formation and provide compelling evidence that oxygen of an acyclic MAO species (i.e., O(AlMe2)2, 4) cannot compete with the O-donor in cyclic MAO species (i.e., (MeAlO)2, 7; MeAl(OAlMe2)2, cyclic 5). Significantly, our work demonstrates that intramolecular O → Al dative bonding results in cyclic isomers of MAO species (i.e., cyclic 5) with high oxophilicities. The stabilities of the [L(R2)FeClax(MAO)eq]+ species demonstrate that 5 provides for the ligating benefits of the cyclic MAO species 4 without the thermodynamically costly elimination of TMA. Mechanistic implications are discussed for the involvement of such Fe–O–Al bridged catalyst in olefin polymerization.
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7
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Collins S, Joshi A, Linnolahti M. Formation and Structure of Hydrolytic Methylaluminoxane Activators. Chemistry 2021; 27:15460-15471. [PMID: 34436806 PMCID: PMC8596698 DOI: 10.1002/chem.202102463] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Indexed: 01/14/2023]
Abstract
Methylaluminoxane (MAO) activators have sheet structures which form ion-pairs on reaction of neutral donors such as octamethyltrisiloxane (OMTS). The ion-pairs can be detected by electrospray ionization mass spectrometry (ESI-MS) in polar media. The growth of these reactive precursors during hydrolysis of Me3 Al can be monitored using ESI-MS. Density functional theory, combined with numerical simulation of growth, indicates that this process involves rapid formation of low MW oligomers, followed by assembly of these species into low MW sheets. These can grow through further addition of low MW oligomers or by fusion into larger sheets. The mechanism of these growth processes leads to the prediction that even-numbered sheets should be favored, and this surprising result is confirmed by ESI-MS monitoring experiments of both activator growth and MAO aging.
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Affiliation(s)
- Scott Collins
- Former affiliation: Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada)
| | - Anuj Joshi
- UVic Genome BC Proteomics Research Centre sup, 4464 Markham St #3101, Victoria, BC V8Z 5N3, Canada
| | - Mikko Linnolahti
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, Yliopistokatu 7, 80100, Joensuu, Finland
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8
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Removal of mononuclear alkylaluminum species in aluminoxane using a crosslinked polymer bearing bulky phenoxy groups. Polym J 2021. [DOI: 10.1038/s41428-021-00507-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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9
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Effect of Intraparticle Mass Transfer on the Catalytic Site Formation in the Preparation of Silica‐Supported Metallocene Catalysts. MACROMOL REACT ENG 2021. [DOI: 10.1002/mren.202100039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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10
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Collins S, Hasan G, Joshi A, McIndoe JS, Linnolahti M. Are Methylaluminoxane Activators Sheets? Chemphyschem 2021; 22:1326-1335. [PMID: 33971081 PMCID: PMC8362195 DOI: 10.1002/cphc.202100268] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/07/2021] [Indexed: 11/14/2022]
Abstract
Density functional theory calculations on neutral sheet models for methylaluminoxane (MAO) indicate that these structures, containing 5‐coordinate and 4‐coordinate Al, are likely precursors to ion‐pairs seen during the hydrolysis of trimethylaluminum (Me3Al) in the presence of donors such as octamethyltrisiloxane (OMTS). Ionization by both methide ([Me]−) and [Me2Al]+ abstraction, involving this donor, were studied by polarizable continuum model calculations in fluorobenzene (PhF) and o‐difluorobenzene (DFB) media. These studies suggest that low MW, 5‐coordinate sheets ionize by [Me2Al]+ abstraction, while [Me]− abstraction from Me3Al‐OMTS is the likely process for higher MW 4‐coordinate sheets. Further, comparison of anion stabilities per mole of aluminoxane repeat unit (MeAlO)n, suggest that anions such as [(MeAlO)7(Me3Al)4Me]−=[7,4]− are especially stable compared to higher homologues, even though their neutral precursors are unstable.
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Affiliation(s)
- Scott Collins
- Department of Chemistry, University of Victoria, 3800, Finnerty Road, Victoria, BC, V8P 5 C2, Canada
| | - Galib Hasan
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, Yliopistokatu 7, 80100, Joensuu, Finland.,Institute for Atmospheric and Earth System Research (INAR) c/o Department of Chemistry, University of Helsinki, A.I Virtasen Aukio 1, 00014, Helsinki, Finland
| | - Anuj Joshi
- Department of Chemistry, University of Victoria, 3800, Finnerty Road, Victoria, BC, V8P 5 C2, Canada.,UVic Genome BC Proteomics Research Centre, 4464, Markham St #3101, Victoria, BC V8Z 5N3, Canada
| | - J Scott McIndoe
- Department of Chemistry, University of Victoria, 3800, Finnerty Road, Victoria, BC, V8P 5 C2, Canada
| | - Mikko Linnolahti
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, Yliopistokatu 7, 80100, Joensuu, Finland
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11
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Joshi A, Collins S, Linnolahti M, Zijlstra HS, Liles E, McIndoe JS. Spectroscopic Studies of Synthetic Methylaluminoxane: Structure of Methylaluminoxane Activators. Chemistry 2021; 27:8753-8763. [PMID: 33780574 DOI: 10.1002/chem.202100271] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Indexed: 11/06/2022]
Abstract
Hydrolysis of trimethylaluminum (Me3 Al) in polar solvents can be monitored by electrospray ionization mass spectrometry (ESI-MS) using the donor additive octamethyltrisiloxane [(Me3 SiO)2 SiMe2 , OMTS]. Using hydrated salts, hydrolytic methylaluminoxane (h-MAO) features different anion distributions, depending on the conditions of synthesis, and different activator contents as measured by NMR spectroscopy. Non-hydrolytic MAO was prepared using trimethylboroxine. The properties of this material, which contains incorporated boron, differ significantly from h-MAO. In the case of MAO prepared by direct hydrolysis, oligomeric anions are observed to rapidly form, and then more slowly evolve into a mixture dominated by an anion with m/z 1375 with formula [(MeAlO)16 (Me3 Al)6 Me]- . Theoretical calculations predict that sheet structures with composition (MeAlO)n (Me3 Al)m are favoured over other motifs for MAO in the size range suggested by the ESI-MS experiments. A possible precursor to the m/z 1375 anion is a local minimum based on the free energy released upon hydrolysis of Me3 Al.
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Affiliation(s)
- Anuj Joshi
- Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
| | - Scott Collins
- C/o Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
| | - Mikko Linnolahti
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, Yliopistokatu 7, 80100, Joensuu, Finland
| | - Harmen S Zijlstra
- Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
| | - Elena Liles
- Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
| | - J Scott McIndoe
- Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
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12
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Kilpatrick AFR, Geddes HS, Turner ZR, Buffet JC, Goodwin AL, O'Hare D. Polymethylaluminoxane organic frameworks (sMAOF) – highly active supports for slurry phase ethylene polymerisation. Catal Sci Technol 2021. [DOI: 10.1039/d1cy00767j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A series of modified solid polymethylaluminoxane (sMAO) catalyst supports have been developed for slurry phase ethylene polymerisation, using aryl di-ol modifier groups.
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Affiliation(s)
| | | | - Zoë R. Turner
- Chemistry Research Laboratory
- Department of Chemistry
- University of Oxford
- Oxford
- UK
| | - Jean-Charles Buffet
- Chemistry Research Laboratory
- Department of Chemistry
- University of Oxford
- Oxford
- UK
| | | | - Dermot O'Hare
- Chemistry Research Laboratory
- Department of Chemistry
- University of Oxford
- Oxford
- UK
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13
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Joshi A, Zijlstra HS, Liles E, Concepcion C, Linnolahti M, McIndoe JS. Real-time analysis of methylalumoxane formation. Chem Sci 2020; 12:546-551. [PMID: 34163784 PMCID: PMC8178985 DOI: 10.1039/d0sc05075j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Methylalumoxane (MAO), a perennially useful activator for olefin polymerization precatalysts, is famously intractable to structural elucidation, consisting as it does of a complex mixture of oligomers generated from hydrolysis of pyrophoric trimethylaluminum (TMA). Electrospray ionization mass spectrometry (ESI-MS) is capable of studying those oligomers that become charged during the activation process. We have exploited that ability to probe the synthesis of MAO in real time, starting less than a minute after the mixing of H2O and TMA and tracking the first half hour of reactivity. We find that the process does not involve an incremental build-up of oligomers; instead, oligomerization to species containing 12–15 aluminum atoms happens within a minute, with slower aggregation to higher molecular weight ions. The principal activated product of the benchtop synthesis is the same as that observed in industrial samples, namely [(MeAlO)16(Me3Al)6Me]−, and we have computationally located a new sheet structure for this ion 94 kJ mol−1 lower in Gibbs free energy than any previously calculated. The activator methylaluminoxane is made by hydrolysis of trimethylaluminum. Analysis using ESI-MS reveals rapid formation of small oligomers is followed by slower aggregation to the larger precursors most capable of releasing [Me2Al]+.![]()
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Affiliation(s)
- Anuj Joshi
- Department of Chemistry, University of Victoria PO Box 1700 STN CSC, Victoria BC V8W 2Y2 Canada
| | - Harmen S Zijlstra
- Department of Chemistry, University of Victoria PO Box 1700 STN CSC, Victoria BC V8W 2Y2 Canada
| | - Elena Liles
- Department of Chemistry, University of Victoria PO Box 1700 STN CSC, Victoria BC V8W 2Y2 Canada
| | - Carina Concepcion
- Department of Chemistry, University of Victoria PO Box 1700 STN CSC, Victoria BC V8W 2Y2 Canada
| | - Mikko Linnolahti
- Department of Chemistry, University of Eastern Finland P.O. Box 111 FI-80101 Joensuu Finland
| | - J Scott McIndoe
- Department of Chemistry, University of Victoria PO Box 1700 STN CSC, Victoria BC V8W 2Y2 Canada
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14
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Teixeira VE, Livotto PR. The mechanism of the reaction between MAO and TMA: DFT study of the electronic structure and characterization of transition states for [AlOMe] 6, [AlOMe] 9 and [AlOMe] 16 cages. J Mol Graph Model 2020; 99:107626. [PMID: 32447271 DOI: 10.1016/j.jmgm.2020.107626] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/02/2020] [Accepted: 04/20/2020] [Indexed: 10/24/2022]
Abstract
Methylaluminoxane (MAO) and trimethylaluminium (TMA) are relevant compounds in organometallic catalysis. Despite many published studies, aspects of their interaction persist an unsolved puzzle. Hence, in this work, we used quantum mechanic approaches based on density functional theory to study this topic. Our calculations revealed that interaction between MAO and TMA occurs initially by the formation of an intermediary Lewis adduct. In agreement with the latent acidity concept, the activation energy for the tensioned Al-O bond break is small, and changes with the local environment of the MAO cages. Breakage of bond belonging to two square faces requires between 4.20 and 5.80 kcal/mol, whereas square-hexagonal faces demand 0.61-9.43 kcal/mol. The products of this reaction present a terminal, acidic 3-coordinate aluminum atom, that can be capped by another TMA molecules. However, our computations suggest that entropic effects may prevent this reaction from occurring at all these sites in the MAO models studied. Additionally, we also characterize the inter/intramolecular methane elimination mechanism. These reactions are not feasible at room temperature but may occur at high temperatures.
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Affiliation(s)
- Vinícius Esteves Teixeira
- Institute of Chemistry - Federal University of Rio Grande do Sul UFRGS, Av. Bento Gonçalves, 9500 CEP 91501-970, Porto Alegre, Brazil.
| | - Paolo Roberto Livotto
- Institute of Chemistry - Federal University of Rio Grande do Sul UFRGS, Av. Bento Gonçalves, 9500 CEP 91501-970, Porto Alegre, Brazil
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15
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Zaccaria F, Budzelaar PHM, Cipullo R, Zuccaccia C, Macchioni A, Busico V, Ehm C. Reactivity Trends of Lewis Acidic Sites in Methylaluminoxane and Some of Its Modifications. Inorg Chem 2020; 59:5751-5759. [PMID: 32271565 PMCID: PMC7997381 DOI: 10.1021/acs.inorgchem.0c00533] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Indexed: 11/28/2022]
Abstract
The established model cluster (AlOMe)16(AlMe3)6 for methylaluminoxane (MAO) cocatalyst has been studied by density functional theory, aiming to rationalize the different behaviors of unmodified MAO and TMA-depleted MAO/BHT (TMA = trimethylaluminum; BHT = 2,6-di-tert-butyl-4-methylphenol), highlighted in previous experimental studies. The tendency of the three model Lewis acidic sites A-C to release neutral Al fragments (i.e., AlMe2R; R = Me or bht) or transient aluminum cations (i.e., [AlMeR]+) has been investigated both in the absence and in the presence of neutral N-donors. Sites C are most likely responsible for the activation capabilities of TMA-rich MAO, but TMA depletion destabilizes them, possibly inducing structural rearrangements. The remaining sites A and B, albeit of lower Lewis acidity, should be still able to release cationic Al fragments when TMA-depleted modified MAOs are treated with N-donors (e.g. [AlMe(bht)]+ from MAO/BHT). These findings provide tentative interpretations for earlier observations of donor-dependent ionization tendencies of MAO and MAO/BHT and how TMA depleted MAOs can still be potent activators.
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Affiliation(s)
- Francesco Zaccaria
- Dipartimento
di Scienze Chimiche, Università di
Napoli Federico II, Via Cintia, 80126 Napoli, Italy
- Dipartimento
di Chimica, Biologia e Biotecnologie and CIRCC, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Peter H. M. Budzelaar
- Dipartimento
di Scienze Chimiche, Università di
Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Roberta Cipullo
- Dipartimento
di Scienze Chimiche, Università di
Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Cristiano Zuccaccia
- Dipartimento
di Chimica, Biologia e Biotecnologie and CIRCC, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Alceo Macchioni
- Dipartimento
di Chimica, Biologia e Biotecnologie and CIRCC, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Vincenzo Busico
- Dipartimento
di Scienze Chimiche, Università di
Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Christian Ehm
- Dipartimento
di Scienze Chimiche, Università di
Napoli Federico II, Via Cintia, 80126 Napoli, Italy
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16
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Zaccaria F, Sian L, Zuccaccia C, Macchioni A. Ion pairing in transition metal catalyzed olefin polymerization. ADVANCES IN ORGANOMETALLIC CHEMISTRY 2020. [DOI: 10.1016/bs.adomc.2019.08.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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17
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Venderbosch B, Oudsen JH, Martin DJ, Bruin B, Korstanje TJ, Tromp M. Investigating the Active Species in a [(R‐SN(H)S‐R)CrCl
3
] Ethene Trimerization System: Mononuclear or Dinuclear? ChemCatChem 2019. [DOI: 10.1002/cctc.201901640] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Bas Venderbosch
- Sustainable Materials Characterization Van ‘t Hoff Institute for Molecular SciencesUniversity of Amsterdam Science Park 904 Amsterdam 1098XH The Netherlands
| | - Jean‐Pierre H. Oudsen
- Sustainable Materials Characterization Van ‘t Hoff Institute for Molecular SciencesUniversity of Amsterdam Science Park 904 Amsterdam 1098XH The Netherlands
| | - David J. Martin
- Sustainable Materials Characterization Van ‘t Hoff Institute for Molecular SciencesUniversity of Amsterdam Science Park 904 Amsterdam 1098XH The Netherlands
| | - Bas Bruin
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Van ‘t Hoff Institute for Molecular SciencesUniversity of Amsterdam Science Park 904 Amsterdam 1098XH The Netherlands
| | - Ties J. Korstanje
- Sustainable Materials Characterization Van ‘t Hoff Institute for Molecular SciencesUniversity of Amsterdam Science Park 904 Amsterdam 1098XH The Netherlands
| | - Moniek Tromp
- Sustainable Materials Characterization Van ‘t Hoff Institute for Molecular SciencesUniversity of Amsterdam Science Park 904 Amsterdam 1098XH The Netherlands
- Materials Chemistry Zernike Institute for Advanced MaterialsUniversity of Groningen Nijenborgh 4 Groningen 9747AG The Netherlands
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18
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Zaccaria F, Zuccaccia C, Cipullo R, Budzelaar PHM, Macchioni A, Busico V, Ehm C. On the Nature of the Lewis Acidic Sites in “TMA‐Free” Phenol‐Modified Methylaluminoxane. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201901035] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Francesco Zaccaria
- Dipartimento di Scienze Chimiche Università di Napoli Federico II Via Cintia 80126 Napoli Italy
- Dipartimento di Chimica Biologia e Biotecnologie and CIRCC Università di Perugia Via Elce di Sotto 8 06123 Perugia Italy
| | - Cristiano Zuccaccia
- Dipartimento di Chimica Biologia e Biotecnologie and CIRCC Università di Perugia Via Elce di Sotto 8 06123 Perugia Italy
| | - Roberta Cipullo
- Dipartimento di Scienze Chimiche Università di Napoli Federico II Via Cintia 80126 Napoli Italy
| | - Peter H. M. Budzelaar
- Dipartimento di Scienze Chimiche Università di Napoli Federico II Via Cintia 80126 Napoli Italy
| | - Alceo Macchioni
- Dipartimento di Chimica Biologia e Biotecnologie and CIRCC Università di Perugia Via Elce di Sotto 8 06123 Perugia Italy
| | - Vincenzo Busico
- Dipartimento di Scienze Chimiche Università di Napoli Federico II Via Cintia 80126 Napoli Italy
| | - Christian Ehm
- Dipartimento di Scienze Chimiche Università di Napoli Federico II Via Cintia 80126 Napoli Italy
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19
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Zijlstra HS, Joshi A, Linnolahti M, Collins S, McIndoe JS. Interaction of Neutral Donors with Methylaluminoxane. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201900153] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Harmen S. Zijlstra
- Department of Chemistry; University of Victoria; P. O. Box 3065 Victoria BC V8W3V6 Canada
| | - Anuj Joshi
- Department of Chemistry; University of Victoria; P. O. Box 3065 Victoria BC V8W3V6 Canada
| | - Mikko Linnolahti
- Department of Chemistry; University of Eastern Finland; P. O. Box 111 80101 Joensuu Finland
| | - Scott Collins
- Department of Chemistry; University of Victoria; P. O. Box 3065 Victoria BC V8W3V6 Canada
| | - J. Scott McIndoe
- Department of Chemistry; University of Victoria; P. O. Box 3065 Victoria BC V8W3V6 Canada
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20
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Zaccaria F, Zuccaccia C, Cipullo R, Budzelaar PHM, Macchioni A, Busico V, Ehm C. BHT-Modified MAO: Cage Size Estimation, Chemical Counting of Strongly Acidic Al Sites, and Activation of a Ti-Phosphinimide Precatalyst. ACS Catal 2019. [DOI: 10.1021/acscatal.9b00076] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Francesco Zaccaria
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
- Dipartimento di Chimica, Biologia e Biotecnologie and CIRCC, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Cristiano Zuccaccia
- Dipartimento di Chimica, Biologia e Biotecnologie and CIRCC, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Roberta Cipullo
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Peter H. M. Budzelaar
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Alceo Macchioni
- Dipartimento di Chimica, Biologia e Biotecnologie and CIRCC, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Vincenzo Busico
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Christian Ehm
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
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21
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Zijlstra HS, Joshi A, Linnolahti M, Collins S, McIndoe JS. Modifying methylalumoxane via alkyl exchange. Dalton Trans 2018; 47:17291-17298. [PMID: 30480693 DOI: 10.1039/c8dt04242j] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Methylalumoxane (MAO) ionizes highly selectively in the presence of octamethyltrisiloxane (OMTS) to generate [Me2Al·OMTS]+ [(MeAlO)16(Me3Al)6Me]-. We can take advantage of this transformation to examine the reactivity of a key component of MAO using electrospray ionization mass spectrometry (ESI-MS), and here we describe the reactivity of this pair of ions with other trialkyl aluminum (R3Al) components. Using continuous injection methods, we found Et3Al to exchange much faster and extensively at room temperature in fluorobenzene (t½∼2 s, up to 25 exchanges of Me for Et) than iBu3Al (t½∼40 s, up to 11 exchanges) or Oct3Al (t½∼200 s, up to 7 exchanges). The exchanges are reversible and the methyl groups on the cation are also observed to exchange with the added R3Al species. These results point to the reactive components of MAO having a structure that deviates significantly from the cage-like motifs studied to date.
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Affiliation(s)
- Harmen S Zijlstra
- Department of Chemistry, University of Victoria, P. O. Box 3065, Victoria BC V8W 3V6, Canada.
| | - Anuj Joshi
- Department of Chemistry, University of Victoria, P. O. Box 3065, Victoria BC V8W 3V6, Canada.
| | - Mikko Linnolahti
- Department of Chemistry, University of Eastern Finland, P. O. Box 111, FI-80101 Joensuu, Finland
| | - Scott Collins
- Department of Chemistry, University of Victoria, P. O. Box 3065, Victoria BC V8W 3V6, Canada.
| | - J Scott McIndoe
- Department of Chemistry, University of Victoria, P. O. Box 3065, Victoria BC V8W 3V6, Canada.
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22
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Endres E, Zijlstra HS, Collins S, McIndoe JS, Linnolahti M. Oxidation of Methylalumoxane Oligomers: A Theoretical Study Guided by Mass Spectrometry. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00587] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Erik Endres
- Department of Chemistry, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
- Faculty of Chemistry & Pharmacy, Julius-Maximilians University, P.O. Box 97074, Würzburg 97070, Germany
| | - Harmen S. Zijlstra
- Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, British Columbia V8W 3 V6, Canada
| | - Scott Collins
- Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, British Columbia V8W 3 V6, Canada
| | - J. Scott McIndoe
- Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, British Columbia V8W 3 V6, Canada
| | - Mikko Linnolahti
- Department of Chemistry, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
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23
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Velthoen MEZ, Muñoz-Murillo A, Bouhmadi A, Cecius M, Diefenbach S, Weckhuysen BM. The Multifaceted Role of Methylaluminoxane in Metallocene-Based Olefin Polymerization Catalysis. Macromolecules 2018; 51:343-355. [PMID: 29910511 PMCID: PMC5997399 DOI: 10.1021/acs.macromol.7b02169] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 12/02/2017] [Indexed: 01/26/2023]
Abstract
![]()
In
single-site olefin polymerization catalysis, a large excess
of cocatalyst is often required for the generation of highly active
catalysts, but the reason for this is unclear. In this work, fundamental
insight into the multifaceted role of cocatalyst methylaluminoxane
(MAO) in the activation, deactivation, and stabilization of group
4 metallocenes in the immobilized single-site olefin polymerization
catalyst was gained. Employing probe molecule FT-IR spectroscopy,
it was found that weak Lewis acid sites, inherent to the silica-supported
MAO cocatalyst, are the main responsible species for the genesis of
active metallocenes for olefin polymerization. These weak Lewis acid
sites are the origin of AlMe2+ groups. Deactivation
of metallocenes is caused by the presence of silanol groups on the
silica support. Interaction of the catalyst precursor with these silanol
groups leads to the irreversible formation of inactive metallocenes.
Importantly, a high concentration of MAO (14 wt% Al) on the silica
support is necessary to keep the metallocenes immobilized, hence preventing
metallocene leaching and consequent reactor fouling. Increasing the
loading of the MAO cocatalyst leads to larger amounts of AlMe2+, fewer silanol groups, and less metallocene leaching,
which all result in higher olefin polymerization activity.
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Affiliation(s)
- Marjolein E Z Velthoen
- Inorganic Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Ara Muñoz-Murillo
- Inorganic Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Abdelkbir Bouhmadi
- Albemarle Europe SPRL, Parc Scientifique de LLN, Rue du Bosquet 9, B-1348 Louvain-la-Neuve, Belgium
| | - Michaël Cecius
- Albemarle Europe SPRL, Parc Scientifique de LLN, Rue du Bosquet 9, B-1348 Louvain-la-Neuve, Belgium
| | - Steve Diefenbach
- Albemarle Corporation, Gulf States Road, Baton Rouge, Louisiana 70801, United States
| | - Bert M Weckhuysen
- Inorganic Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
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24
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Kilpatrick AFR, Rees NH, Sripothongnak S, Buffet JC, O’Hare D. Slurry-Phase Ethylene Polymerization Using Pentafluorophenyl- and Pentafluorophenoxy-Modified Solid Polymethylaluminoxanes. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00846] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alexander F. R. Kilpatrick
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, U.K
| | - Nicholas H. Rees
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, U.K
| | | | - Jean-Charles Buffet
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, U.K
| | - Dermot O’Hare
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, U.K
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25
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Parfenova LV, Kovyazin PV, Tyumkina TV, Islamov DN, Lyapina AR, Karchevsky SG, Ivchenko PV. Reactions of bimetallic Zr,Al- hydride complexes with methylaluminoxane: NMR and DFT study. J Organomet Chem 2017. [DOI: 10.1016/j.jorganchem.2017.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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26
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Linnolahti M, Collins S. Formation, Structure, and Composition of Methylaluminoxane. Chemphyschem 2017; 18:3369-3374. [PMID: 28857416 DOI: 10.1002/cphc.201700827] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 08/31/2017] [Indexed: 11/12/2022]
Abstract
The structurally ill-characterized methylaluminoxane (MAO) is the activator of choice in olefin polymerization catalysis. We have carried out large scale and systematic quantum chemical calculations to simulate the thermodynamics of its formation by controlled hydrolysis of trimethylaluminum (TMA), extending the studies up to 25 Al atoms, and thus, to the real size domain of MAO. In agreement with previous postulates on its structure, MAO is shown to favor cage-like structures, which commonly contain associated TMA, regardless of size or shape. The sites containing associated TMA are reactive, and explain the function of MAO as a catalyst activator. The compositions of MAOs show overall agreement with experiments, and exhibit structural transitions from chains to rings to sheets to eventually cages as a function of size. The most stable cage structure is obtained for a composition of (MeAlO)16 (Me3 Al)6 , which is in precise agreement with mass spectrometric studies of corresponding anions, and adapts a tubular molecular structure with a molecular weight of 1360 g mol-1 . Our mass spectrometric measurements enable detection of both major and minor anion species.
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Affiliation(s)
- Mikko Linnolahti
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, FI-80101, Joensuu, Finland
| | - Scott Collins
- Department of Chemistry, University of Victoria, 3800 Finnerty Rd., Victoria, BC, Canada
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27
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Zijlstra HS, Linnolahti M, Collins S, McIndoe JS. Additive and Aging Effects on Methylalumoxane Oligomers. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00153] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Harmen S. Zijlstra
- Department
of Chemistry, University of Victoria, P.O. Box 3065, Victoria, British Columbia V8W 3V6, Canada
| | - Mikko Linnolahti
- Department
of Chemistry, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
| | - Scott Collins
- Department
of Chemistry, University of Victoria, P.O. Box 3065, Victoria, British Columbia V8W 3V6, Canada
| | - J. Scott McIndoe
- Department
of Chemistry, University of Victoria, P.O. Box 3065, Victoria, British Columbia V8W 3V6, Canada
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28
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Kelley P, Edouard GA, Lin S, Agapie T. Lewis Acid Accelerated Aryl Ether Bond Cleavage with Nickel: Orders of Magnitude Rate Enhancement Using AlMe3. Chemistry 2016; 22:17173-17176. [PMID: 27717036 DOI: 10.1002/chem.201604160] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Indexed: 01/08/2023]
Affiliation(s)
- Paul Kelley
- Division of Chemistry and Chemical Engineering; California Institute of Technology; Pasadena CA 91125 MC 127-72 USA
| | - Guy A. Edouard
- Division of Chemistry and Chemical Engineering; California Institute of Technology; Pasadena CA 91125 MC 127-72 USA
| | - Sibo Lin
- Division of Chemistry and Chemical Engineering; California Institute of Technology; Pasadena CA 91125 MC 127-72 USA
| | - Theodor Agapie
- Division of Chemistry and Chemical Engineering; California Institute of Technology; Pasadena CA 91125 MC 127-72 USA
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29
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Influence of trimethylaluminum on kinetics of rac -Et(Ind) 2 ZrCl 2 /aluminoxane catalyzed ethylene polymerization. J Organomet Chem 2016. [DOI: 10.1016/j.jorganchem.2016.02.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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30
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Quantitative structure–property relationships in propene polymerization by zirconocenes with a rac-SiMe2[Ind]2 based ligand framework. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.molcata.2015.11.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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31
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Falls Z, Zurek E, Autschbach J. Computational prediction and analysis of the 27Al solid-state NMR spectrum of methylaluminoxane (MAO) at variable temperatures and field strengths. Phys Chem Chem Phys 2016; 18:24106-18. [PMID: 27526292 DOI: 10.1039/c6cp04260k] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
27Al MAS NMR of the co-catalyst methylaluminoxane may be able to reveal the fraction of species that are catalytically active.
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Affiliation(s)
- Zackary Falls
- Department of Chemistry
- University at Buffalo
- State University of New York
- Buffalo
- USA
| | - Eva Zurek
- Department of Chemistry
- University at Buffalo
- State University of New York
- Buffalo
- USA
| | - Jochen Autschbach
- Department of Chemistry
- University at Buffalo
- State University of New York
- Buffalo
- USA
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32
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Tymińska N, Zurek E. DFT-D Investigation of Active and Dormant Methylaluminoxane (MAO) Species Grafted onto a Magnesium Dichloride Cluster: A Model Study of Supported MAO. ACS Catal 2015. [DOI: 10.1021/acscatal.5b01697] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nina Tymińska
- Department
of Chemistry, State University of New York at Buffalo, Buffalo, New York 14260-3000, United States
| | - Eva Zurek
- Department
of Chemistry, State University of New York at Buffalo, Buffalo, New York 14260-3000, United States
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33
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Kuklin MS, Hirvi JT, Bochmann M, Linnolahti M. Toward Controlling the Metallocene/Methylaluminoxane-Catalyzed Olefin Polymerization Process by a Computational Approach. Organometallics 2015. [DOI: 10.1021/acs.organomet.5b00394] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mikhail S. Kuklin
- Department of Chemistry, University of Eastern Finland, Joensuu
Campus, FI-80101 Joensuu, Finland
| | - Janne T. Hirvi
- Department of Chemistry, University of Eastern Finland, Joensuu
Campus, FI-80101 Joensuu, Finland
| | - Manfred Bochmann
- Wolfson Materials and Catalysis Centre, School of Chemistry, University of East Anglia, Earlham Road, Norwich, NR4 7TJ, United Kingdom
| | - Mikko Linnolahti
- Department of Chemistry, University of Eastern Finland, Joensuu
Campus, FI-80101 Joensuu, Finland
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