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Romano E, Barone V, Budzelaar PHM, De Rosa C, Talarico G. Revisiting Stereoselective Propene Polymerization Mechanisms: Insights through the Activation Strain Model. Chem Asian J 2024; 19:e202400155. [PMID: 38494455 DOI: 10.1002/asia.202400155] [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: 02/11/2024] [Revised: 03/08/2024] [Accepted: 03/12/2024] [Indexed: 03/19/2024]
Abstract
The stereoelectronic factors responsible for stereoselectivity in propene polymerization with several metallocene and post-metallocene transition metal catalysts have been revisited using a combined approach of DFT calculations, the Activation Strain Model, Natural Energy Decomposition Analysis and a molecular descriptor (%VBur). There are in most cases two different paths leading to the formation of stereoerrors (SE), and the classical model does not suffice to fully understand stereoregulation. Improving stereoselectivity requires raising the energies of both SE insertion transition states. Our analyses show that the degrees of deformation of the active site (catalyst+chain) and the prochiral monomer differ for these two paths, and between different catalyst classes. Based on such analyses we discuss: a) the subtle differences in SE formation between stereoselective catalysts with different ligand frameworks; b) the reason for exceptional stereoselectivity reported for a special ansa-metallocene catalyst; c) the (double) stereocontrol origin for isoselective catalysts; d) the electronic contribution for isoselective catalysts generating SE by a modification of the ligand wrapping mode during the polymerization. Although this study will not immediately suggest new catalyst structures, we believe that understanding stereoregulation in great detail will increase our chances of success.
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Affiliation(s)
- Eugenio Romano
- Scuola Superiore Meridionale, Largo San Marcellino 10, 80138, Napoli, Italy
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126, Pisa, Italy
- Dipartimento di Scienze Chimiche, Università degli Studi di, Napoli Federico II, Via Cintia, 80126, Napoli, Italy
| | | | - Peter H M Budzelaar
- Dipartimento di Scienze Chimiche, Università degli Studi di, Napoli Federico II, Via Cintia, 80126, Napoli, Italy
| | - Claudio De Rosa
- Dipartimento di Scienze Chimiche, Università degli Studi di, Napoli Federico II, Via Cintia, 80126, Napoli, Italy
| | - Giovanni Talarico
- Scuola Superiore Meridionale, Largo San Marcellino 10, 80138, Napoli, Italy
- Dipartimento di Scienze Chimiche, Università degli Studi di, Napoli Federico II, Via Cintia, 80126, Napoli, Italy
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Rana TRK, Swain A, Rajaraman G. The role of agostic interaction in the mechanism of ethylene polymerisation using Cr(III) half-sandwich complexes: What dictates the reactivity? Dalton Trans 2023; 52:11826-11834. [PMID: 37555755 DOI: 10.1039/d3dt02032k] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
Chromium-based catalysts play a significant role in the production of ultra-high molecular weight polyethylene, and half-sandwich functionalised-metallocene complexes were proven to be one of the most suitable candidates as catalysts for generating such large polymeric-length olefins. Earlier experimental studies on olefin polymerisation using a series of catalysts such as [L1-2CrCl2] (where L1 = 1-((pyridin-2-yl)methyl)indenyl (1) and L2 = 2-methyl-1-{[4-(yridinene-1-yl)yridine-2-yl]methyl}-1H-indenyl (2)) reveal significant variation where peripheral substitution on the ligand was found to influence the reactivity significantly. However, the specific ligand position that affects the reactivity has not been established. As these reactions are fast and robust, it is challenging to establish reactive intermediates via experiments, and therefore, mechanistic clues for such reactions are elusive. Here we have undertaken a detailed computational study by employing an array of DFT (uB3LYP-D3/def2-TZVP, CASSCF/NEVPT2, and DLPNO-CCSD(T) methods to explore the substituted and non-substituted pyridine-cyclo-pentadienyl chromium complexes and their influence on the catalytic activity in ethylene polymerisation. Our study not only unravels the catalytic pathway for olefin polymerisation for such Cr(III)-half-sandwich complexes but also reveals that the energetics of the formation of pseudo-three-coordinate alkyl intermediates is key to the variation in the reactivity observed. A detailed examination using MO and NBO analysis unveils the presence of a C-H⋯Cr agostic interaction that is found to significantly stabilise this intermediate when the pyridine ligand has strong electron-donating groups at its para position. The other substitutions, such as on the cyclopentadienyl ligand, neither yield the desired stability nor the desired interaction. Further studies on models support this proposal. In order to improve the efficiency and selectivity of catalytic systems in olefin polymerisation, we strongly advocate for the integration of agostic interactions as a crucial criterion in the design of future catalysts. Considering the prevalence of electron-deficient metal centres in successful olefin polymerisation catalysts, this research prompts a broader mechanistic inquiry to propose a unified approach for this industrially crucial reaction.
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Affiliation(s)
| | - Abinash Swain
- Department of Chemistry, Indian Institute of Technology, Powai, Mumbai, India.
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology, Powai, Mumbai, India.
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D'Anania O, De Rosa C, Talarico G. A Computational Evaluation of the Steric and Electronic Contributions in Stereoselective Olefin Polymerization with Pyridylamido-Type Catalysts. Molecules 2023; 28:molecules28093768. [PMID: 37175175 PMCID: PMC10180424 DOI: 10.3390/molecules28093768] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/21/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
A density functional theory (DFT) study combined with the steric maps of buried volume (%VBur) as molecular descriptors and an energy decomposition analysis through the ASM (activation strain model)-NEDA (natural energy decomposition analysis) approach were applied to investigate the origins of stereoselectivity for propene polymerization promoted by pyridylamido-type nonmetallocene systems. The relationships between the fine tuning of the ligand and the propene stereoregularity were rationalized (e.g., the metallacycle size, chemical nature of the bridge, and substituents at the ortho-position on the aniline moieties). The DFT calculations and %VBur steric maps reproduced the experimental trend: substituents on the bridge and on the ortho-positions of aniline fragments enhance the stereoselectivity. The ASM-NEDA analysis enabled the separation of the steric and electronic effects and revealed how subtle ligand modification may affect the stereoselectivity of the process.
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Affiliation(s)
- Olga D'Anania
- Scuola Superiore Meridionale, Largo San Marcellino, 80138 Napoli, Italy
| | - Claudio De Rosa
- Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, 80124 Napoli, Italy
| | - Giovanni Talarico
- Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, 80124 Napoli, Italy
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Romano E, Budzelaar PHM, De Rosa C, Talarico G. Unconventional Stereoerror Formation Mechanisms in Nonmetallocene Propene Polymerization Systems Revealed by DFT Calculations. J Phys Chem A 2022; 126:6203-6209. [PMID: 36054494 PMCID: PMC9483984 DOI: 10.1021/acs.jpca.2c04935] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
An unconventional
mechanism for the stereoerror formation in propene
polymerization catalyzed by C1-symmetric
salalen-M systems (M = Zr, Hf) is suggested by DFT calculations. While
propagation happens with the ligand in its fac-mer conformation, a change of ligand wrapping mode from fac-mer to fac-fac is the main source of the lower stereoselectivities
obtained with Zr and Hf. This is different for the Ti analogues, where
the ligand fac-mer wrapping mode
does not play a role. Activation strain analysis indicates that the
preference for a chain stationary mechanism of the Zr/Hf species is
due to the energy required to distort the reactants (ΔEStrain) rather than to their mutual interaction
(ΔEInt).
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Affiliation(s)
- Eugenio Romano
- Scuola Superiore Meridionale, Largo San Marcellino 10, 80138 Napoli, Italy
| | - Peter H M Budzelaar
- Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Claudio De Rosa
- Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | - Giovanni Talarico
- Scuola Superiore Meridionale, Largo San Marcellino 10, 80138 Napoli, Italy.,Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
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Cuthbert ENT, Vittoria A, Cipullo R, Busico V, Budzelaar PHM. Structure-Activity Relationships for Bis(phenolate-ether) Zr/Hf Propene Polymerization Catalysts. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.201901315] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Eric N. T. Cuthbert
- Department of Chemistry; University of Manitoba; 144 Dysart Road MB R3T 2N2 Winnipeg Canada
- Dutch Polymer Institute (DPI); P.O. Box 902 5600 AX Eindhoven The Netherlands
| | - Antonio Vittoria
- Dutch Polymer Institute (DPI); P.O. Box 902 5600 AX Eindhoven The Netherlands
- Dipartimento di Scienze Chimiche; Università di Napoli “Federico II”; Via Cintia 80126 Napoli Italy
| | - Roberta Cipullo
- Dutch Polymer Institute (DPI); P.O. Box 902 5600 AX Eindhoven The Netherlands
- Dipartimento di Scienze Chimiche; Università di Napoli “Federico II”; Via Cintia 80126 Napoli Italy
| | - 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 80126 Napoli Italy
| | - Peter H. M. Budzelaar
- Department of Chemistry; University of Manitoba; 144 Dysart Road MB R3T 2N2 Winnipeg Canada
- Dutch Polymer Institute (DPI); P.O. Box 902 5600 AX Eindhoven The Netherlands
- Dipartimento di Scienze Chimiche; Università di Napoli “Federico II”; Via Cintia 80126 Napoli Italy
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Nifant’ev I, Ivchenko P, Tavtorkin A, Vinogradov A, Vinogradov A. Non-traditional Ziegler-Natta catalysis in α-olefin transformations: reaction mechanisms and product design. PURE APPL CHEM 2017. [DOI: 10.1515/pac-2016-1131] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
AbstractThis paper describes our recent results in the field of zirconocene-catalyzed α-oltfin transformations, and focuses on questions regarding the reaction mechanism, rational design of zirconocene pre-catalysts, as well as prospective uses of α-olefin products. It has been determined that a wide range of α-olefin-based products, namely vinylidene dimers, oligomers and polymers, can be prepared via catalysis by zirconocene dichlorides, activated by a minimal (10–20 eq.) amount of MAO. We assumed that in the presence of minimal quantities of MAO, various types of zirconocene catalysts form different types of catalytic particles. In the case of bis-cyclopentadienyl complexes, the reactive center is formed under the influence of R2AlCl, which makes the chain termination via β-hydride elimination significantly easier, with α-olefin dimers being formed as the primary product. Bis-indenyl complexes and their heteroanalogues, form stable cationic catalytic particles and effectively catalyze the polymerization. Mono-indenyl and mono-substituted bis-cyclopentadienyl-ansa complexes catalyze α-olefin oligomerization. Effective catalysts of dimerization, oligomerization and polymerization of α-olefins in the presence of minimal MAO quantities are proposed. Prospects of using α-olefin dimers, oligomers and polymers in the synthesis of branched hydrocarbon functional derivatives (dimers), high quality, low viscosity motor oils (oligomers), and thickeners and absorbents (polymers) are examined.
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Affiliation(s)
- Ilya Nifant’ev
- Department of Chemistry, M.V. Lomonosov Moscow University, Moscow, Russia
- A.V. Topchiev Institute of Petrochemical Synthesis RAS, Moscow, Russia
| | - Pavel Ivchenko
- A.V. Topchiev Institute of Petrochemical Synthesis RAS, Moscow, Russia
| | | | - Alexey Vinogradov
- A.V. Topchiev Institute of Petrochemical Synthesis RAS, Moscow, Russia
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Xu X, He G, Wei NN, Hao C, Pan Y. Selective Insertion in Copolymerization of Ethylene and Styrene Catalyzed by Half-Titanocene System Bearing Ketimide Ligand: A Theoretical Study. CHINESE J CHEM 2017. [DOI: 10.1002/cjoc.201700282] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Xiaowei Xu
- State Key Laboratory of Fine Chemicals, School of Petroleum and Chemical Engineering; Dalian University of Technology; Panjin Liaoning 124221 China
| | - Gaohong He
- State Key Laboratory of Fine Chemicals, School of Petroleum and Chemical Engineering; Dalian University of Technology; Panjin Liaoning 124221 China
| | - Ning-Ning Wei
- School of Life Science and Medicine; Dalian University of Technology; Panjin Liaoning 124221 China
| | - Ce Hao
- State Key Laboratory of Fine Chemicals, School of Petroleum and Chemical Engineering; Dalian University of Technology; Panjin Liaoning 124221 China
| | - Yu Pan
- State Key Laboratory of Fine Chemicals, School of Petroleum and Chemical Engineering; Dalian University of Technology; Panjin Liaoning 124221 China
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Zaccaria F, Cipullo R, Budzelaar PHM, Busico V, Ehm C. Backbone rearrangement during olefin capture as the rate limiting step in molecular olefin polymerization catalysis and its effect on comonomer affinity. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/pola.28685] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Francesco Zaccaria
- Dipartimento di Scienze Chimiche; Università di Napoli Federico II; Napoli 80126 Italy
| | - Roberta Cipullo
- Dipartimento di Scienze Chimiche; Università di Napoli Federico II; Napoli 80126 Italy
| | - Peter H. M. Budzelaar
- Dipartimento di Scienze Chimiche; Università di Napoli Federico II; Napoli 80126 Italy
- Department of Chemistry; University of Manitoba; Winnipeg Manitoba Canada R3T 2N2
| | - Vincenzo Busico
- Dipartimento di Scienze Chimiche; Università di Napoli Federico II; Napoli 80126 Italy
| | - Christian Ehm
- Dipartimento di Scienze Chimiche; Università di Napoli Federico II; Napoli 80126 Italy
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Zaccaria F, Ehm C, Budzelaar PHM, Busico V. Accurate Prediction of Copolymerization Statistics in Molecular Olefin Polymerization Catalysis: The Role of Entropic, Electronic, and Steric Effects in Catalyst Comonomer Affinity. ACS Catal 2017. [DOI: 10.1021/acscatal.6b03458] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [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
| | - Christian Ehm
- Dipartimento di
Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
| | | | - Vincenzo Busico
- Dipartimento di
Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126 Napoli, Italy
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10
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Geer AM, López JA, Ciriano MA, Tejel C. Agostic versus Terminal Ethyl Rhodium Complexes: A Combined Experimental and Theoretical Study. Organometallics 2016. [DOI: 10.1021/acs.organomet.6b00036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ana M. Geer
- Departamento
Química
Inorgánica, Instituto de Síntesis Química y Catálisis
Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna
12, 50009-Zaragoza, Spain
| | - José A. López
- Departamento
Química
Inorgánica, Instituto de Síntesis Química y Catálisis
Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna
12, 50009-Zaragoza, Spain
| | - Miguel A. Ciriano
- Departamento
Química
Inorgánica, Instituto de Síntesis Química y Catálisis
Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna
12, 50009-Zaragoza, Spain
| | - Cristina Tejel
- Departamento
Química
Inorgánica, Instituto de Síntesis Química y Catálisis
Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna
12, 50009-Zaragoza, Spain
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Pan Y, Xu X, Wei NN, Hao C, Zhu X, He G. DFT study on 1,7-octadiene polymerization catalyzed by a non-bridged half-titanocene system. RSC Adv 2016. [DOI: 10.1039/c6ra14867k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
For (η5-C5Me5)TiCl2(O-2,6-iPr2C6H3)/MAO system, the selectivity of repeated insertion and intramolecular cyclization of 1,7-octadiene were explored in detail by DFT method.
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Affiliation(s)
- Yu Pan
- State Key Laboratory of Fine Chemicals
- School of Petroleum and Chemical Engineering
- Dalian University of Technology
- Panjin 124221
- P. R. China
| | - Xiaowei Xu
- State Key Laboratory of Fine Chemicals
- School of Petroleum and Chemical Engineering
- Dalian University of Technology
- Panjin 124221
- P. R. China
| | - Ning-Ning Wei
- School of Life Science and Medicine
- Dalian University of Technology
- Panjin 124221
- P. R. China
| | - Ce Hao
- State Key Laboratory of Fine Chemicals
- School of Petroleum and Chemical Engineering
- Dalian University of Technology
- Panjin 124221
- P. R. China
| | - Xiaodong Zhu
- SINOPEC Zhenhai Refining and Chemical Company
- Ningbo 315207
- P. R. China
| | - Gaohong He
- State Key Laboratory of Fine Chemicals
- School of Petroleum and Chemical Engineering
- Dalian University of Technology
- Panjin 124221
- P. R. China
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