1
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Collins S, Linnolahti M. Sheet Models for Methylaluminoxane (MAO) Activators? A Theoretical Case Study involving rac-Me 2Si(η 5-C 9H 6) 2Zr (SBIZr) Complexes. Chemphyschem 2024; 25:e202300856. [PMID: 38469662 DOI: 10.1002/cphc.202300856] [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: 11/14/2023] [Revised: 03/09/2024] [Accepted: 03/10/2024] [Indexed: 03/13/2024]
Abstract
Activation of SBIZrMe2 or SBIZrMeCl and a sheet model for an active component of hydrolytic MAO, (MeAlO)16(Me3Al)6, (16,6) has been studied by DFT. Contact ion-pair formation occurs through the intermediacy of SBIZrMe(Cl) or SBIZrMe2 reacting with sheet 16,6 to furnish SBIZrMe-μ-X(MeAlO)16(Me3Al)6 (2, X=Me, Cl). Contact ion-pairs 2 would be in equilibrium with heterodinuclear catalyst precursors [SBIZrMe2AlMe2][(MeAlO)16(Me3Al)6X] (3 (X=Me, Cl) through reversible binding of Me3Al at higher Al : Zr ratios. Calculations show that formation of ion-pairs 3 from contact ion-pairs 2 is more favourable for the SBIZr compared with the parent Cp2Zr complexes. TD-DFT calculations were conducted on relevant SBIZr complexes to relate the results to earlier spectroscopic studies of catalyst activation using UV-Vis spectroscopy. Finally, propene insertion into ion-pairs 2, SBIZrMe-μ-MeB(C6F5)3 (6) and [SBIZrMe][B(C6F5)4] (7) was studied at M06-2X/TZVP level of theory. These studies suggest that contact ion-pairs 2 are significantly less reactive towards insertion than 6 or 7, in disagreement with experiment.
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Affiliation(s)
- Scott Collins
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, Yliopistokatu 7, FI-80100, Joensuu, Finland
| | - Mikko Linnolahti
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, Yliopistokatu 7, FI-80100, Joensuu, Finland
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2
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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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3
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Collins S, Linnolahti M. Ionization of Cp 2 ZrMe 2 and Lewis Bases by Methylaluminoxane: Computational Insights. Chemphyschem 2023; 24:e202200759. [PMID: 36321588 DOI: 10.1002/cphc.202200759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 10/20/2022] [Indexed: 11/06/2022]
Abstract
The interactions of the Lewis bases CO, octamethyltrisiloxane (OMTS) and 2,2'-bipyridine (bipy) with a sheet model for the principal activator (MeAlO)16 (Me3 Al)6 (16,6) in hydrolytic methylaluminoxane (MAO) were investigated by DFT. These studies reveal that OMTS and bipy form adducts with Me3 Al prior to methide abstraction by 16,6 to form the ion-pairs [Me2 Al(κ2 -L)][16,6] (5: L=OMTS, 6: L=bipy, [16,6]- =[(MeAlO)16 (Me3 Al)6 Me]- ) while CO simply binds to a reactive edge site without ionization. The binding and activation of Cp2 ZrMe2 with 16,6 to form both neutral adducts 1 Cp2 ZrMe2 ⋅16,6 and contact ion-pairs 4 and 7, both with formula [Cp2 ZrMe][μ-Me(MeAlO)16 (Me3 Al)6 ], featuring terminal and chelated MAO-anions, respectively was studied by DFT. The displacement of the anion with either excess Cp2 ZrMe2 or Me3 Al was also studied, forming outer-sphere ion-pairs [(Cp2 ZrMe)2 μ-Me][16,6] (2) and [Cp2 Zr(μ-Me)2 AlMe2 ][16,6] (3). The theoretical NMR spectra of these species were compared to experimental spectra of MAO and Cp2 ZrMe2 and found to be in good agreement with the reported data and assignments. These studies confirm that 16,6 is a very suitable model for the activators present in MAO but highlight the difficulty in accurately calculating thermodynamic quantities for molecules in this size regime.
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Affiliation(s)
- Scott Collins
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, Yliopistokatu 7, F80100, Joensuu, Finland.,Former address: Department of Chemistry, University of Victoria, 3800 Finnerty Rd., Victoria, BC, Canada
| | - Mikko Linnolahti
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, Yliopistokatu 7, F80100, Joensuu, Finland
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4
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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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5
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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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6
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Kenyon P, Leung DJ, Lyu M, Chen C, Turner ZR, Buffet JC, O'Hare D. Controlling the activity of an immobilised molecular catalyst by Lewis acidity tuning of the support. J Catal 2021. [DOI: 10.1016/j.jcat.2021.08.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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7
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Nakashima T, Nakayama Y, Shiono T, Tanaka R. Neutral, Noncoordinating, and Hydrocarbon-Soluble Protic Cocatalyst for Olefin Polymerization. ACS Catal 2021. [DOI: 10.1021/acscatal.0c04758] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tomoya Nakashima
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
| | - Yuushou Nakayama
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
| | - Takeshi Shiono
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
| | - Ryo Tanaka
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
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8
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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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9
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Tanaka R. Precise control of coordination polymerization via the modification of methylaluminoxane (MAO). Polym J 2020. [DOI: 10.1038/s41428-020-0325-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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10
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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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11
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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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12
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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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13
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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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14
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Zaccaria F, Zuccaccia C, Cipullo R, Macchioni A. Extraction of Reliable Molecular Information from Diffusion NMR Spectroscopy: Hydrodynamic Volume or Molecular Mass? Chemistry 2019; 25:9930-9937. [PMID: 30998838 DOI: 10.1002/chem.201900812] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Indexed: 01/31/2023]
Abstract
Measuring accurate translational self-diffusion coefficients (Dt ) by NMR techniques with modern spectrometers has become rather routine. In contrast, the derivation of reliable molecular information therefrom still remains a nontrivial task. In this paper, two established approaches to estimating molecular size in terms of hydrodynamic volume (VH ) or molecular weight (M) are compared. Ad hoc designed experiments allowed the critical aspects of their application to be explored by translating relatively complex theoretical principles into practical take-home messages. For instance, comparing the Dt values of three isosteric Cp2 MCl2 complexes (Cp=cyclopentadienyl, M=Ti, Zr, Hf), having significantly different molecular mass, provided an empirical demonstration that VH is the critical molecular property affecting Dt . This central concept served to clarify the assumptions behind the derivation of Dt =ƒ(M) power laws from the Stokes-Einstein equation. Some pitfalls in establishing log (Dt ) versus log (M) linear correlations for a set of species have been highlighted by further investigations of selected examples. The effectiveness of the Stokes-Einstein equation itself in describing the aggregation or polymerization of differently shaped species has been explored by comparing, for example, a ball-shaped silsesquioxane cage with its cigar-like dimeric form, or styrene with polystyrene macromolecules.
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Affiliation(s)
- Francesco Zaccaria
- 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
| | - Alceo Macchioni
- Dipartimento di Chimica, Biologia e Biotecnologie and CIRCC, Università di Perugia, Via Elce di Sotto 8, 06123, Perugia, Italy
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15
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Ye J, Li Y, Jiang B, Zhang W, Wang J, Liao Z, Huang Z, Yang Y, Ye Z. Effects of Methylaluminoxane Modifications on Tuning the Bis(Imino)Pyridyl Iron‐Catalyzed Oligomerization of Ethylene. POLYM ENG SCI 2019. [DOI: 10.1002/pen.25056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jian Ye
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological EngineeringZhejiang University Hangzhou 310027 People's Republic of China
| | - Yu Li
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological EngineeringZhejiang University Hangzhou 310027 People's Republic of China
| | - Binbo Jiang
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological EngineeringZhejiang University Hangzhou 310027 People's Republic of China
| | - Wei Zhang
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological EngineeringZhejiang University Hangzhou 310027 People's Republic of China
| | - Jingdai Wang
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological EngineeringZhejiang University Hangzhou 310027 People's Republic of China
- State Key Laboratory of Chemical EngineeringZhejiang University Hangzhou 310027 People's Republic of China
| | - Zuwei Liao
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological EngineeringZhejiang University Hangzhou 310027 People's Republic of China
- State Key Laboratory of Chemical EngineeringZhejiang University Hangzhou 310027 People's Republic of China
| | - Zhengliang Huang
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological EngineeringZhejiang University Hangzhou 310027 People's Republic of China
| | - Yongrong Yang
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological EngineeringZhejiang University Hangzhou 310027 People's Republic of China
- State Key Laboratory of Chemical EngineeringZhejiang University Hangzhou 310027 People's Republic of China
| | - Zhibin Ye
- Department of Chemical and Materials EngineeringConcordia University Montreal Quebec H3G 1M8 Canada
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16
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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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17
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Wang J, Xie J, Wang L, Jiang Y, Zhang N. The effect of phenolic compounds on salicylaldimine nickel-catalyzed ethylene oligomerization. CAN J CHEM 2019. [DOI: 10.1139/cjc-2018-0292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A salen nickel complex has been prepared in good yield with ethylenediamine, salicylaldehyde, and NiCl2·6H2O as raw materials. The structure of the complex was characterized by FTIR, 1H NMR, UV, and ESI-MS. Upon activation with methylaluminoxane (MAO), the precatalyst showed high activity for ethylene oligomerization. To reduce the simultaneous production of insoluble polymers during the nickel-catalyzed ethylene oligomerization, a series of phenolic compounds were introduced as modifiers for the production of linear α-olefins. The researched result showed that the phenolic compounds have a significant impact on the selectivity of oligomers and the concentration of polymers. With the increase of phenolic compounds, the content of polymers decreased and the distribution of oligomers gradually shifted toward lighter olefins. The sterically hindered 4-tert-butyphenol proved to be an especially efficient polymer-retarding modifier among the studied phenolic compounds in this work. Furthermore, the retarding effect of phenolic compounds toward insoluble polymers may be mainly related to their interaction with MAO, giving rise to larger MAO aggregates.
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Affiliation(s)
- Jun Wang
- Provincial Key Laboratory of Oil & Gas Chemical Technology, College of Chemistry & Chemical Engineering, Northeast Petroleum University, Daqing 163318, Heilongjiang Province, China
| | - Junyi Xie
- Provincial Key Laboratory of Oil & Gas Chemical Technology, College of Chemistry & Chemical Engineering, Northeast Petroleum University, Daqing 163318, Heilongjiang Province, China
| | - Libo Wang
- Daqing Chemical Research Center of Petrochemical Research Institute, Daqing, 163714, China
| | - Yan Jiang
- Daqing Chemical Research Center of Petrochemical Research Institute, Daqing, 163714, China
| | - Na Zhang
- Provincial Key Laboratory of Oil & Gas Chemical Technology, College of Chemistry & Chemical Engineering, Northeast Petroleum University, Daqing 163318, Heilongjiang Province, China
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18
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Propene oligomerisation at ambient temperature with [Cp(C5H4SiMe2tol)ZrMe2] (Cp = C5H5; tol = p-C6H5Me). Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2018.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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19
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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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20
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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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21
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TANAKA R, YAMASHITA T, TONOKO N, NAKAYAMA Y, SHIONO T. Effect of Added Phenols and Silanol on the Cocatalyst Activity of Methylaluminoxane. KOBUNSHI RONBUNSHU 2018. [DOI: 10.1295/koron.2018-0024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ryo TANAKA
- Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University
| | - Takayuki YAMASHITA
- Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University
| | - Naoki TONOKO
- Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University
| | - Yuushou NAKAYAMA
- Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University
| | - Takeshi SHIONO
- Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University
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22
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Preparation of Aryloxy-aluminoxanes and Their Use as Activators in the Bis(imino)pyridyl Iron-catalyzed Oligomerization of Ethylene. CHINESE JOURNAL OF POLYMER SCIENCE 2018. [DOI: 10.1007/s10118-018-2146-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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23
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Zijlstra HS, Collins S, McIndoe JS. Oxidation of Methylalumoxane Oligomers. Chemistry 2018; 24:5506-5512. [PMID: 29342315 DOI: 10.1002/chem.201705458] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Indexed: 11/07/2022]
Abstract
The anions formed from methylalumoxane (MAO) and suitable donors (e.g. octamethyltrisiloxane) are amenable to mass spectrometric (MS) analysis. Their composition as deduced from this data allows direct insight into the chemical transformations of their neutral precursors. One such process is oxidation, which is well-known to be facile for MAO without any clear idea of what actually occurs at a molecular level. Addition of O2 to MAO results in immediate gelation, but MS analysis reveals no corresponding change to the composition of the principal oligomeric anions. A slow (hours) reaction does occur that involves net incorporation of Me2 AlOMe into the oligomeric anions, and the identities of the OMe-containing anions were confirmed by 1 H NMR spectroscopy, MS/MS analysis, and addition of an authentic sample of Me2 AlOMe to MAO. The result tallies with the fact that addition of O2 to MAO produces Me2 AlOMe from free Me3 Al which eventually leads to formation of oxidized MAO oligomers and changes in ion abundance. Aging of the oxygenated MAO results in further growth of the oligomers similar to that of the non-oxidized species. Mass spectrometric analysis therefore reveals useful insights into the environmental history of a given MAO batch.
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Affiliation(s)
- Harmen S Zijlstra
- Department of Chemistry, University of Victoria, P. O. Box 3065, Victoria, BC, V8W3V6, Canada
| | - 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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24
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Multi-Alkenylsilsesquioxanes as Comonomers and Active Species Modifiers of Metallocene Catalyst in Copolymerization with Ethylene. Polymers (Basel) 2018; 10:polym10020223. [PMID: 30966258 PMCID: PMC6415135 DOI: 10.3390/polym10020223] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 02/16/2018] [Accepted: 02/22/2018] [Indexed: 12/24/2022] Open
Abstract
The copolymers of ethylene (E) with open-caged iso-butyl-substituted tri-alkenyl-silsesquioxanes (POSS-6-3 and POSS-10-3) and phenyl-substituted tetra-alkenyl-silsesquioxane (POSS-10-4) were synthesized by copolymerization over the ansa-metallocene catalyst. The influence of the kind of silsesquioxane and of the copolymerization conditions on the reaction performance and on the properties of the copolymers was studied. In the case of copolymerization of E/POSS-6-3, the positive comonomer effect was observed, which was associated with the influence of POSS-6-3 on transformation of the bimetallic ion pair to the active catalytic species. Functionality of silsesquioxanes and polymerization parameters affected the polyhedral oligomeric silsesquioxanes (POSS) contents in the copolymers which varied in the range of 1.33–7.43 wt %. Tri-alkenyl-silsesquioxanes were incorporated into the polymer chain as pendant groups while the tetra-alkenyl-silsesquioxane derivative could act as a cross-linking agent which was proved by the changes in the contents of unsaturated end groups, by the glass transition temperature values, and by the gel contents (up to 81.3% for E/POSS-10-4). Incorporation of multi-alkenyl-POSS into the polymer chain affected also the melting and crystallization behaviors.
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25
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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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26
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Collins S, Linnolahti M, Zamora MG, Zijlstra HS, Rodríguez Hernández MT, Perez-Camacho O. Activation of Cp2ZrX2 (X = Me, Cl) by Methylaluminoxane As Studied by Electrospray Ionization Mass Spectrometry: Relationship to Polymerization Catalysis. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b00933] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Scott Collins
- Department
of Chemistry, University of Victoria, 3800 Finnerty Rd. Victoria, BC, Canada
- Centro de Investigacion en Quimica Aplicada, CP 25294 Saltillo, COAH, Mexico
| | - Mikko Linnolahti
- Department
of Chemistry, Joensuu Campus, University of Eastern Finland, P.O. Box 111 FI-80101 Joensuu, Finland
| | | | - Harmen S. Zijlstra
- Department
of Chemistry, University of Victoria, 3800 Finnerty Rd. Victoria, BC, Canada
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27
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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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28
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Characterization of Halogen Bonded Adducts in Solution by Advanced NMR Techniques. MAGNETOCHEMISTRY 2017. [DOI: 10.3390/magnetochemistry3040030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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29
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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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30
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Abstract
Quenched-flow data for propene polymerization with rac-Me2Si(2-Me-4-Ph-1-indenyl)2ZrCl2/MAO support a picture where removal of MAO qualitatively changes the kinetic profile from a mainly enthalpic to a mainly entropic barrier. DFT studies suggest that a not previously recognized singly-bridged end-on coordination mode of Me6Al2 to catalytically active centers may be kinetically relevant as a resting state. In contrast, the more traditional doubly-bridged complex of Me3Al is proposed to be more relevant to chain transfer to cocatalyst.
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Affiliation(s)
- C Ehm
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy.
| | - R Cipullo
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy.
| | - P H M Budzelaar
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - V Busico
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy.
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31
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Rocchigiani L, Busico V, Pastore A, Macchioni A. Comparative NMR Study on the Reactions of Hf(IV) Organometallic Complexes with Al/Zn Alkyls. Organometallics 2016. [DOI: 10.1021/acs.organomet.6b00088] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Luca Rocchigiani
- Dipartimento
di Chimica, Biologia e Biotecnologie and CIRCC, Università degli Studi di Perugia, Via Elce di sotto, 8, I-06123 Perugia, Italy
- Dutch Polymer Institute (DPI) P.O. Box
902, 5600 AX Eindhoven, The Netherlands
| | - Vincenzo Busico
- Dutch Polymer Institute (DPI) P.O. Box
902, 5600 AX Eindhoven, The Netherlands
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, I-80126 Napoli, Italy
| | - Antonello Pastore
- Dutch Polymer Institute (DPI) P.O. Box
902, 5600 AX Eindhoven, The Netherlands
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, I-80126 Napoli, Italy
| | - Alceo Macchioni
- Dipartimento
di Chimica, Biologia e Biotecnologie and CIRCC, Università degli Studi di Perugia, Via Elce di sotto, 8, I-06123 Perugia, Italy
- Dutch Polymer Institute (DPI) P.O. Box
902, 5600 AX Eindhoven, The Netherlands
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32
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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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33
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Rocchigiani L, Macchioni A. Disclosing the multi-faceted world of weakly interacting inorganic systems by means of NMR spectroscopy. Dalton Trans 2016; 45:2785-90. [DOI: 10.1039/c5dt04620c] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The potential of NMR spectroscopy to investigate inorganic systems whose structure and reactivity is affected by non-covalent interactions is described; supramolecular assemblies based on relatively unusual intermolecular forces or on more classical ones, still rather unexplored in solution, are considered.
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Affiliation(s)
| | - Alceo Macchioni
- Department of Chemistry
- Biology and Biotechnology and CIRCC
- University of Perugia
- Perugia
- Italy
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34
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Kuklin MS, Virkkunen V, Castro PM, Resconi L, Linnolahti M. Controlling the Microstructure of Isotactic Polypropene byC2-Symmetric Zirconocene Polymerization Catalysts: Influence of Alkyl Substituents on Regio- and Stereocontrol. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500862] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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35
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Zijlstra HS, Stuart MCA, Harder S. Structural Investigation of Methylalumoxane Using Transmission Electron Microscopy. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b00803] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Harmen S. Zijlstra
- Stratingh
Institute, University of Groningen, Nijenborgh 4, 9747AG Groningen, Netherlands
- Dutch Polymer Institute (DPI), P.O. Box 902, 5600AX Eindhoven, Netherlands
| | - Marc C. A. Stuart
- Stratingh
Institute, University of Groningen, Nijenborgh 4, 9747AG Groningen, Netherlands
| | - Sjoerd Harder
- Inorganic
and Organometallic Chemistry, University of Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany
- Dutch Polymer Institute (DPI), P.O. Box 902, 5600AX Eindhoven, Netherlands
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36
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Ye J, Jiang B, Qin Y, Zhang W, Chen Y, Wang J, Yang Y. Exploring the effects of phenolic compounds on bis(imino)pyridine iron-catalyzed ethylene oligomerization. RSC Adv 2015. [DOI: 10.1039/c5ra19972g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Polymer formation could be efficiently retarded with the activation of phenol-modified MAOs in the iron-catalyzed oligomerization of ethylene.
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Affiliation(s)
- Jian Ye
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- P. R. China
| | - Binbo Jiang
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- P. R. China
| | - Yichao Qin
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- P. R. China
| | - Wei Zhang
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- P. R. China
| | - Yuming Chen
- 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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37
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Trefz TK, Henderson MA, Linnolahti M, Collins S, McIndoe JS. Mass spectrometric characterization of methylaluminoxane-activated metallocene complexes. Chemistry 2014; 21:2980-91. [PMID: 25556910 DOI: 10.1002/chem.201405319] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Indexed: 11/11/2022]
Abstract
Electrospray-ionization mass spectrometric studies of poly(methylaluminoxane) (MAO) in the presence of [Cp2 ZrMe2 ], [Cp2 ZrMe(Cl)], and [Cp2 ZrCl2 ] in fluorobenzene (PhF) solution are reported. The results demonstrate that alkylation and ionization are separate events that occur at competitive rates in a polar solvent. Furthermore, there are significant differences in ion-pair speciation that result from the use of metallocene dichloride complexes in comparison to alkylated precursors at otherwise identical Al/Zr ratios. Finally, the counter anions that form are dependent on the choice of precursor and Al/Zr ratio; halogenated aluminoxane anions [(MeAlO)x (Me3 Al)y-z (Me2 AlCl)z Me](-) (z=1, 2, 3…︁) are observed using metal chloride complexes and under some conditions may predominate over their non-halogenated precursors [(MeAlO)x (Me3 Al)y Me](-) . Specifically, this halogenation process appears selective for the anions that form in comparison to the neutral components of MAO. Only at very high Al/Zr ratios is the same "native" anion distribution observed when using [Cp2 ZrCl2 ] when compared with [Cp2 ZrMe2 ]. Together, the results suggest that the need for a large excess of MAO when using metallocene dichloride complexes is a reflection of competitive alkylation vs. ionization, the persistence of unreactive, homodinuclear ion pairs in the case of [Cp2 ZrCl2 ], as well as a change in ion pairing resulting from modification of the anions formed at lower Al/Zr ratios. Models for neutral precursors and anions are examined computationally.
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Affiliation(s)
- Tyler K Trefz
- Department of Chemistry, University of Victoria, P.O. Box 3065 Victoria, BC V8W3V6 (Canada)
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38
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Zijlstra HS, Harder S. Methylalumoxane – History, Production, Properties, and Applications. Eur J Inorg Chem 2014. [DOI: 10.1002/ejic.201402978] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Harmen S. Zijlstra
- Stratingh Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
- Dutch Polymer Institute (DPI), P. O. Box 902, 5600 AX Eindhoven, Netherlands
| | - Sjoerd Harder
- Dutch Polymer Institute (DPI), P. O. Box 902, 5600 AX Eindhoven, Netherlands
- Inorganic and Organometallic Chemistry, University of Erlangen‐Nürnberg, Egerlandstr. 1, 91058 Erlangen, Germany, http://www.harder‐research.com
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39
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Hirvi JT, Bochmann M, Severn JR, Linnolahti M. Formation of octameric methylaluminoxanes by hydrolysis of trimethylaluminum and the mechanisms of catalyst activation in single-site α-olefin polymerization catalysis. Chemphyschem 2014; 15:2732-42. [PMID: 24930450 DOI: 10.1002/cphc.201402298] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Indexed: 11/10/2022]
Abstract
Hydrolysis of trimethylaluminum (TMA) leads to the formation of methylaluminoxanes (MAO) of general formula (MeAlO)n (AlMe3)m. The thermodynamically favored pathway of MAO formation is followed up to n=8, showing the major impact of associated TMA on the structural characteristics of the MAOs. The MAOs bind up to five TMA molecules, thereby inducing transition from cages into rings and sheets. Zirconocene catalyst activation studies using model MAO co-catalysts show the decisive role of the associated TMA in forming the catalytically active sites. Catalyst activation can take place either by Lewis-acidic abstraction of an alkyl or halide ligand from the precatalyst or by reaction of the precatalyst with an MAO-derived AlMe2(+) cation. Thermodynamics suggest that activation through AlMe2(+) transfer is the dominant mechanism because sites that are able to release AlMe2(+) are more abundant than Lewis-acidic sites. The model catalyst system is demonstrated to polymerize ethene.
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Affiliation(s)
- Janne T Hirvi
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, 80101 Joensuu (Finland)
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40
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Soshnikov IE, Semikolenova NV, Antonov AA, Bryliakov KP, Zakharov VA, Talsi EP. 1H and 2H NMR Spectroscopic Characterization of Heterobinuclear Ion Pairs Formed upon the Activation of Bis(imino)pyridine Vanadium(III) Precatalysts with AlMe3/[Ph3C]+[B(C6F5)4]− and MAO. Organometallics 2014. [DOI: 10.1021/om500267e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Igor E. Soshnikov
- Boreskov
Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russian Federation
- Novosibirsk State University, 630090, Novosibirsk, Russian Federation
| | - Nina V. Semikolenova
- Boreskov
Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russian Federation
| | - Artem A. Antonov
- Boreskov
Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russian Federation
- Novosibirsk State University, 630090, Novosibirsk, Russian Federation
| | - Konstantin P. Bryliakov
- Boreskov
Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russian Federation
- Novosibirsk State University, 630090, Novosibirsk, Russian Federation
| | - Vladimir A. Zakharov
- Boreskov
Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russian Federation
- Novosibirsk State University, 630090, Novosibirsk, Russian Federation
| | - Evgenii P. Talsi
- Boreskov
Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russian Federation
- Novosibirsk State University, 630090, Novosibirsk, Russian Federation
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41
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Li G, Zuccaccia C, Tedesco C, D'Auria I, Macchioni A, Pellecchia C. NMR spectroscopy and X-ray characterisation of cationic N-heteroaryl-pyridylamido Zr(IV) complexes: a further level of complexity for the elusive active species of pyridylamido olefin polymerisation catalysts. Chemistry 2014; 20:232-44. [PMID: 24285639 DOI: 10.1002/chem.201303021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Indexed: 11/09/2022]
Abstract
New [(N(-),N,N(-))ZrR2] dialkyl complexes (N(-),N,N(-)=pyrrolyl-pyridyl-amido or indolyl-pyridyl-amido; R=Me or CH2Ph) have been synthesised and tested as pre-catalysts for ethene and propene polymerisation in combination with different activators, such as B(C6F5)3, [Ph3C][B(C6F5)4], [HNMe2Ph][B(C6F5)4] or solid AlMe3-depleted methylaluminoxane (DMAO). Polyethylene (M(w)>2 MDa and M(w)/M(n)= 1.3-1.6) has been produced if pre-catalysts were activated with 1000 equivalents of DMAO (based on Al) [activity >1000 kg(PE)(mol([Zr]) h mol atm)(-1)] or by using a higher pre-catalyst concentration and a mixture of [HNPhMe2][B(C6F5)4] (1 equiv) and AliBu2H (60 equiv). In the case of propene polymerisation, activity has been observed only if pre-catalysts were treated with an excess of AliBu2H prior to addition of DMAO, which led to highly isotactic polypropylene ([mmmm]>95%). Neutral pre-catalysts and ion pairs derived from their activation have been characterised in solution by using advanced 1D and 2D NMR spectroscopy experiments. The detection and rationalisation of intercationic NOEs clearly showed the formation of dimeric species in which some pyrrolyl or indolyl π-electron density of one unit is engaged in stabilising the metal centre of the other unit, which relegates the counterions in the second coordination sphere. The solid-state structure of the dimeric indolyl-pyridyl-amidomethylzirconium derivative, determined by X-ray diffraction studies, points toward a weak Zr···η(3)-indolyl interaction. It can be hypothesised that the formation of dimeric cationic species hampers monomer coordination (especially of less reactive α-olefins) and that addition of AliBu2H is crucial to split the homodimers.
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Affiliation(s)
- Gang Li
- Dipartimento di Chimica e Biologia, Università di Salerno via Giovanni Paolo II 132, 84084 Fisciano (SA) (Italy); Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, via Elce di Sotto 8, 06123 Perugia (Italy)
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Ghiotto F, Pateraki C, Tanskanen J, Severn JR, Luehmann N, Kusmin A, Stellbrink J, Linnolahti M, Bochmann M. Probing the Structure of Methylalumoxane (MAO) by a Combined Chemical, Spectroscopic, Neutron Scattering, and Computational Approach. Organometallics 2013. [DOI: 10.1021/om4002878] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Fabio Ghiotto
- Wolfson Materials and Catalysis
Centre, School of Chemistry, University of East Anglia, Norwich,
United Kingdom
| | - Chrysoula Pateraki
- Wolfson Materials and Catalysis
Centre, School of Chemistry, University of East Anglia, Norwich,
United Kingdom
| | - Jukka Tanskanen
- Department of Chemistry, University of Eastern Finland, Joensuu Campus, FI-80101 Joensuu, Finland
| | - John R. Severn
- UHMwPE Chemistry & Catalysis, DSM, NL-6160MD Geleen, The Netherlands
| | - Nicole Luehmann
- Jülich Centre for Neutron Science and Institute for Complex
Systems, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - André Kusmin
- Jülich Centre for Neutron Science and Institute for Complex
Systems, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Jörg Stellbrink
- Jülich Centre for Neutron Science and Institute for Complex
Systems, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Mikko Linnolahti
- 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, Norwich,
United Kingdom
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