Ph2Si-bridged constrained-geometry complexes of hafnium and titanium for copolymerization of ethylene and 1-octene: an experimental and computational comparison.
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| Title: | Ph |
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| Authors: | Kuchuk, Ekaterina1 (AUTHOR), Giffin, Kaitie A.2 (AUTHOR), Welle, Alexandre2 (AUTHOR), Dauw, Katty Den2 (AUTHOR), Fernandez, Alvaro2 (AUTHOR), Cordier, Marie3 (AUTHOR), Roisnel, Thierry3 (AUTHOR), Carpentier, Jean-Francois1 (AUTHOR) jean-francois.carpentier@univ-rennes.fr, Kirillov, Evgueni1 (AUTHOR) evgueni.kirillov@univ-rennes.fr |
| Source: | Dalton Transactions: An International Journal of Inorganic Chemistry. 5/19/2026, Vol. 55 Issue 19, p7512-7520. 9p. |
| Subjects: | Copolymerization, Titanium catalysts, Hafnium compounds, Density functional theory, Octene, Ethylene, Metallocene catalysts |
| Abstract: | A series of new constrained-geometry hafnium and titanium complexes, including {Me2Si(2,7-tBu2Flu)NtBu}HfCl2 (1-HfCl2), {Ph2Si(2,7-tBu2Flu)NtBu}HfCl2 (2-HfCl2) and {Ph2Si(2,7-tBu2Flu)NtBu}TiCl2 (2-TiCl2), was synthesized and fully characterized using solution NMR spectroscopy and X-ray crystallography. These complexes were subsequently evaluated in the copolymerization of ethylene with 1-octene ([C8]0 = 0.48–1.88 M), revealing striking differences in catalytic performance and properties of the resulting polyolefin elastomers/plastomers (POE/POP). The hafnium complexes 1-HfCl2 and 2-HfCl2 exhibited low catalytic activity, yielding polymers with broad molecular weight distributions and only modest incorporation of 1-octene. In contrast, the titanium complex 2-TiCl2 demonstrated significantly higher catalytic activity and achieved substantial 1-octene incorporation at an ethylene/1-octene molar ratio of ca. 6 : 1, with values reaching up to 36.6 mol%. 2-TiCl2 exhibited approximately half the productivity of benchmark CGC {Me4CpSiMe2NtBu}TiCl2 (3-TiCl2), yet yielding POE with a much higher molecular weight and a density of 0.8547 g cm−3. DFT calculations were also performed for the cationic catalytic species derived from the pre-catalysts 2-HfCl2 and 2-TiCl2 to rationalize the relative performance of the titled systems in incorporating ethylene and 1-octene and undergoing termination and transfer reactions. A +5.6 kcal mol−1 energy difference (in terms of ΔΔH‡) was computed between the transition states for the third ethylene insertion into the M–C(polymeryl) bond for the Hf-based system compared to the Ti-based system; other phenomena possibly plaguing efficiency of the Hf-system are discussed. [ABSTRACT FROM AUTHOR] |
| Copyright of Dalton Transactions: An International Journal of Inorganic Chemistry is the property of Royal Society of Chemistry and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
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| Items | – Name: Title Label: Title Group: Ti Data: Ph<subscript>2</subscript>Si-bridged constrained-geometry complexes of hafnium and titanium for copolymerization of ethylene and 1-octene: an experimental and computational comparison. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Kuchuk%2C+Ekaterina%22">Kuchuk, Ekaterina</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Giffin%2C+Kaitie+A%2E%22">Giffin, Kaitie A.</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Welle%2C+Alexandre%22">Welle, Alexandre</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Dauw%2C+Katty+Den%22">Dauw, Katty Den</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Fernandez%2C+Alvaro%22">Fernandez, Alvaro</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Cordier%2C+Marie%22">Cordier, Marie</searchLink><relatesTo>3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Roisnel%2C+Thierry%22">Roisnel, Thierry</searchLink><relatesTo>3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Carpentier%2C+Jean-Francois%22">Carpentier, Jean-Francois</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> jean-francois.carpentier@univ-rennes.fr</i><br /><searchLink fieldCode="AR" term="%22Kirillov%2C+Evgueni%22">Kirillov, Evgueni</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> evgueni.kirillov@univ-rennes.fr</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Dalton+Transactions%3A+An+International+Journal+of+Inorganic+Chemistry%22">Dalton Transactions: An International Journal of Inorganic Chemistry</searchLink>. 5/19/2026, Vol. 55 Issue 19, p7512-7520. 9p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Copolymerization%22">Copolymerization</searchLink><br /><searchLink fieldCode="DE" term="%22Titanium+catalysts%22">Titanium catalysts</searchLink><br /><searchLink fieldCode="DE" term="%22Hafnium+compounds%22">Hafnium compounds</searchLink><br /><searchLink fieldCode="DE" term="%22Density+functional+theory%22">Density functional theory</searchLink><br /><searchLink fieldCode="DE" term="%22Octene%22">Octene</searchLink><br /><searchLink fieldCode="DE" term="%22Ethylene%22">Ethylene</searchLink><br /><searchLink fieldCode="DE" term="%22Metallocene+catalysts%22">Metallocene catalysts</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: A series of new constrained-geometry hafnium and titanium complexes, including {Me2Si(2,7-tBu2Flu)NtBu}HfCl2 (1-HfCl2), {Ph2Si(2,7-tBu2Flu)NtBu}HfCl2 (2-HfCl2) and {Ph2Si(2,7-tBu2Flu)NtBu}TiCl2 (2-TiCl2), was synthesized and fully characterized using solution NMR spectroscopy and X-ray crystallography. These complexes were subsequently evaluated in the copolymerization of ethylene with 1-octene ([C8]0 = 0.48–1.88 M), revealing striking differences in catalytic performance and properties of the resulting polyolefin elastomers/plastomers (POE/POP). The hafnium complexes 1-HfCl2 and 2-HfCl2 exhibited low catalytic activity, yielding polymers with broad molecular weight distributions and only modest incorporation of 1-octene. In contrast, the titanium complex 2-TiCl2 demonstrated significantly higher catalytic activity and achieved substantial 1-octene incorporation at an ethylene/1-octene molar ratio of ca. 6 : 1, with values reaching up to 36.6 mol%. 2-TiCl2 exhibited approximately half the productivity of benchmark CGC {Me4CpSiMe2NtBu}TiCl2 (3-TiCl2), yet yielding POE with a much higher molecular weight and a density of 0.8547 g cm−3. DFT calculations were also performed for the cationic catalytic species derived from the pre-catalysts 2-HfCl2 and 2-TiCl2 to rationalize the relative performance of the titled systems in incorporating ethylene and 1-octene and undergoing termination and transfer reactions. A +5.6 kcal mol−1 energy difference (in terms of ΔΔH‡) was computed between the transition states for the third ethylene insertion into the M–C(polymeryl) bond for the Hf-based system compared to the Ti-based system; other phenomena possibly plaguing efficiency of the Hf-system are discussed. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Dalton Transactions: An International Journal of Inorganic Chemistry is the property of Royal Society of Chemistry and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1039/d6dt00602g Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 9 StartPage: 7512 Subjects: – SubjectFull: Copolymerization Type: general – SubjectFull: Titanium catalysts Type: general – SubjectFull: Hafnium compounds Type: general – SubjectFull: Density functional theory Type: general – SubjectFull: Octene Type: general – SubjectFull: Ethylene Type: general – SubjectFull: Metallocene catalysts Type: general Titles: – TitleFull: Ph2Si-bridged constrained-geometry complexes of hafnium and titanium for copolymerization of ethylene and 1-octene: an experimental and computational comparison. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Kuchuk, Ekaterina – PersonEntity: Name: NameFull: Giffin, Kaitie A. – PersonEntity: Name: NameFull: Welle, Alexandre – PersonEntity: Name: NameFull: Dauw, Katty Den – PersonEntity: Name: NameFull: Fernandez, Alvaro – PersonEntity: Name: NameFull: Cordier, Marie – PersonEntity: Name: NameFull: Roisnel, Thierry – PersonEntity: Name: NameFull: Carpentier, Jean-Francois – PersonEntity: Name: NameFull: Kirillov, Evgueni IsPartOfRelationships: – BibEntity: Dates: – D: 19 M: 05 Text: 5/19/2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 14779226 Numbering: – Type: volume Value: 55 – Type: issue Value: 19 Titles: – TitleFull: Dalton Transactions: An International Journal of Inorganic Chemistry Type: main |
| ResultId | 1 |
