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Pietrzykowski A, Justyniak I, Szejko V, Skrok T, Radzymiński T, Suwińska K, Lewiński J. A New Structural Motif in Aggregation of Methylalumoxanes: Non-Hydrolytic Route by the Alkylation of Dicarboxylic Acids. Chemistry 2024; 30:e202402021. [PMID: 39037004 DOI: 10.1002/chem.202402021] [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: 05/23/2024] [Revised: 07/10/2024] [Accepted: 07/21/2024] [Indexed: 07/23/2024]
Abstract
Alumoxanes are typically produced via controlled hydrolysis of short-chain alkyl aluminium compounds which leads to oligomeric species that are usually difficult to obtain in crystalline form. Simultaneously, various alternative non-hydrolytic approaches to alumoxanes have also been used. In this work, we report on a new methylalumoxane scaffold derived from the alkylation of a series of dicarboxylic acids: itaconic acid (HO2CCH2C(=CH2)CO2H), succinic acid (HO2CCH2CH2CO2H) and homophthalic acid (HO2CCH2C6H4CO2H). The reactions of AlMe3 with a selected dicarboxylic acid in the molar ratio 4 : 1 conducted at elevated temperature occur with double methylation of each carboxylic group and provide to the formation of a new methylalumoxane aggregate, Me10Al6O4, flanked by methylaluminium diolate units. We also aimed to obtain dialkylaluminium derivatives of dicarboxylic acids by the controlled reaction of the appropriate acid with AlMe3 in the 1 : 2 stoichiometry. While the synthesis of organoaluminium derivatives of flexible aliphatic dicarboxylic acids (itaconic and succinic acids) is challenging due to their insolubility, the related homophtalate compound readily forms a molecular tetranuclear cluster, [([(O2CCH2C6H4CO2)(μ-AlMe2)2]2. The molecular and crystal structures of the resulting compounds were determined via NMR spectroscopic analysis and single crystal X-ray diffraction crystallography.
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Affiliation(s)
- Antoni Pietrzykowski
- Warsaw University of Technology, Faculty of Chemistry, Noakowskiego 3, 00-664, Warsaw, Poland
| | - Iwona Justyniak
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Vadim Szejko
- Warsaw University of Technology, Faculty of Chemistry, Noakowskiego 3, 00-664, Warsaw, Poland
| | - Tomasz Skrok
- Warsaw University of Technology, Faculty of Chemistry, Noakowskiego 3, 00-664, Warsaw, Poland
| | - Tomasz Radzymiński
- Warsaw University of Technology, Faculty of Chemistry, Noakowskiego 3, 00-664, Warsaw, Poland
| | - Kinga Suwińska
- Cardinal Stefan Wyszyński University in Warsaw, Faculty of Mathematics and Natural Sciences, K. Wóycickiego 1/3, 01-938, Warsaw, Poland
| | - Janusz Lewiński
- Warsaw University of Technology, Faculty of Chemistry, Noakowskiego 3, 00-664, Warsaw, Poland
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
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Korona K, Justyniak I, Pogrebetsky J, Lemieszka M, Bernatowicz P, Pietrzykowski A, Kubas A, Lewiński J. Controlled hydrolysis of AlMe 3 to tetramethylalumoxane and a new look at incipient adducts with water. Chem Commun (Camb) 2024; 60:9392-9395. [PMID: 39133042 DOI: 10.1039/d4cc03672g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
We present an efficient route to tetramethylalumoxane by the controlled hydrolysis of AlMe3 in the presence of pyridine. The AlMe3(pyr) hydrolysis by 0.5 and 1 equiv. of H2O has been followed with real-time 1H NMR. Based on high-level quantum-chemical calculations, we conclude that hypervalent, pentacoordinate aluminium species are critical in the first steps of hydrolysis.
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Affiliation(s)
- Krzesimir Korona
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
| | - Iwona Justyniak
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - James Pogrebetsky
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - Marta Lemieszka
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
| | - Piotr Bernatowicz
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - Antoni Pietrzykowski
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
| | - Adam Kubas
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - Janusz Lewiński
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
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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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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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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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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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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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