Catalytic Properties of Zirconocene-Based Systems in 1-Hexene Oligomerization and Structure of Metal Hydride Reaction Centers
Despite large-scale investigations of homogeneous single-site metallocene catalysts and systems based on them, there are still unsolved problems related to the control of their activity and chemo- and stereoselectivity. A solution to these problems is required to develop efficient methods for the sy...
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| Format: | Article |
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MDPI AG
2023-03-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/28/6/2420 |
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| author | Lyudmila V. Parfenova Pavel V. Kovyazin Almira Kh. Bikmeeva Eldar R. Palatov Pavel V. Ivchenko Ilya E. Nifant’ev Leonard M. Khalilov |
| author_facet | Lyudmila V. Parfenova Pavel V. Kovyazin Almira Kh. Bikmeeva Eldar R. Palatov Pavel V. Ivchenko Ilya E. Nifant’ev Leonard M. Khalilov |
| author_sort | Lyudmila V. Parfenova |
| collection | DOAJ |
| description | Despite large-scale investigations of homogeneous single-site metallocene catalysts and systems based on them, there are still unsolved problems related to the control of their activity and chemo- and stereoselectivity. A solution to these problems is required to develop efficient methods for the synthesis of practically useful products of alkene transformations, such as dimers, oligomers, and polymers. Here we studied the catalytic activity of structurally diverse zirconocenes (L<sub>2</sub>ZrCl<sub>2</sub>, L = Cp, C<sub>5</sub>Me<sub>5</sub>, Ind, L<sub>2</sub> = Me<sub>2</sub>CCp<sub>2</sub>, Me<sub>2</sub>SiCp<sub>2</sub>, Me<sub>2</sub>C<sub>2</sub>Cp<sub>2</sub>, <i>rac</i>-Me<sub>2</sub>CInd<sub>2</sub>, <i>rac</i>-H<sub>4</sub>C<sub>2</sub>Ind<sub>2</sub>, BIPh(Ind)<sub>2</sub>, H<sub>4</sub>C<sub>2</sub>[THInd]<sub>2</sub>), and co-catalysts activating the system, namely HAlBu<sup>i</sup><sub>2</sub>, MMAO-12, and (Ph<sub>3</sub>C)[B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>], at low activator/Zr ratios in a 1-hexene oligomerization reaction. The influence of catalyst structure and system composition on the alkene conversion, the type of products, and the reaction stereoselectivity were investigated. The composition of hydride intermediates formed in the L<sub>2</sub>ZrCl<sub>2</sub>–HAlBu<sup>i</sup><sub>2</sub>–activator system (L<sub>2</sub> = ansa-Me<sub>2</sub>CCp<sub>2</sub>, Ind) was studied by NMR spectroscopy. Participation of the bis-zirconium hydride complex as the precursor of catalytically active sites of the alkene dimerization reaction was shown. |
| first_indexed | 2024-03-11T06:08:47Z |
| format | Article |
| id | doaj.art-e47804e338344c28b6347eb5d75a372e |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-11T06:08:47Z |
| publishDate | 2023-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-e47804e338344c28b6347eb5d75a372e2023-11-17T12:50:07ZengMDPI AGMolecules1420-30492023-03-01286242010.3390/molecules28062420Catalytic Properties of Zirconocene-Based Systems in 1-Hexene Oligomerization and Structure of Metal Hydride Reaction CentersLyudmila V. Parfenova0Pavel V. Kovyazin1Almira Kh. Bikmeeva2Eldar R. Palatov3Pavel V. Ivchenko4Ilya E. Nifant’ev5Leonard M. Khalilov6Institute of Petrochemistry and Catalysis, Ufa Federal Research Center, Russian Academy of Sciences, Prosp. Oktyabrya, 141, 450075 Ufa, RussiaInstitute of Petrochemistry and Catalysis, Ufa Federal Research Center, Russian Academy of Sciences, Prosp. Oktyabrya, 141, 450075 Ufa, RussiaInstitute of Petrochemistry and Catalysis, Ufa Federal Research Center, Russian Academy of Sciences, Prosp. Oktyabrya, 141, 450075 Ufa, RussiaInstitute of Petrochemistry and Catalysis, Ufa Federal Research Center, Russian Academy of Sciences, Prosp. Oktyabrya, 141, 450075 Ufa, RussiaDepartment of Chemistry, Lomonosov Moscow State University, 1-3 Leninskiye Gory, 119991 Moscow, RussiaDepartment of Chemistry, Lomonosov Moscow State University, 1-3 Leninskiye Gory, 119991 Moscow, RussiaInstitute of Petrochemistry and Catalysis, Ufa Federal Research Center, Russian Academy of Sciences, Prosp. Oktyabrya, 141, 450075 Ufa, RussiaDespite large-scale investigations of homogeneous single-site metallocene catalysts and systems based on them, there are still unsolved problems related to the control of their activity and chemo- and stereoselectivity. A solution to these problems is required to develop efficient methods for the synthesis of practically useful products of alkene transformations, such as dimers, oligomers, and polymers. Here we studied the catalytic activity of structurally diverse zirconocenes (L<sub>2</sub>ZrCl<sub>2</sub>, L = Cp, C<sub>5</sub>Me<sub>5</sub>, Ind, L<sub>2</sub> = Me<sub>2</sub>CCp<sub>2</sub>, Me<sub>2</sub>SiCp<sub>2</sub>, Me<sub>2</sub>C<sub>2</sub>Cp<sub>2</sub>, <i>rac</i>-Me<sub>2</sub>CInd<sub>2</sub>, <i>rac</i>-H<sub>4</sub>C<sub>2</sub>Ind<sub>2</sub>, BIPh(Ind)<sub>2</sub>, H<sub>4</sub>C<sub>2</sub>[THInd]<sub>2</sub>), and co-catalysts activating the system, namely HAlBu<sup>i</sup><sub>2</sub>, MMAO-12, and (Ph<sub>3</sub>C)[B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>], at low activator/Zr ratios in a 1-hexene oligomerization reaction. The influence of catalyst structure and system composition on the alkene conversion, the type of products, and the reaction stereoselectivity were investigated. The composition of hydride intermediates formed in the L<sub>2</sub>ZrCl<sub>2</sub>–HAlBu<sup>i</sup><sub>2</sub>–activator system (L<sub>2</sub> = ansa-Me<sub>2</sub>CCp<sub>2</sub>, Ind) was studied by NMR spectroscopy. Participation of the bis-zirconium hydride complex as the precursor of catalytically active sites of the alkene dimerization reaction was shown.https://www.mdpi.com/1420-3049/28/6/2420zirconocenesmetal hydridesmethylaluminoxaneperfluorophenyl boratesalkene dimerizationoligomerization |
| spellingShingle | Lyudmila V. Parfenova Pavel V. Kovyazin Almira Kh. Bikmeeva Eldar R. Palatov Pavel V. Ivchenko Ilya E. Nifant’ev Leonard M. Khalilov Catalytic Properties of Zirconocene-Based Systems in 1-Hexene Oligomerization and Structure of Metal Hydride Reaction Centers Molecules zirconocenes metal hydrides methylaluminoxane perfluorophenyl borates alkene dimerization oligomerization |
| title | Catalytic Properties of Zirconocene-Based Systems in 1-Hexene Oligomerization and Structure of Metal Hydride Reaction Centers |
| title_full | Catalytic Properties of Zirconocene-Based Systems in 1-Hexene Oligomerization and Structure of Metal Hydride Reaction Centers |
| title_fullStr | Catalytic Properties of Zirconocene-Based Systems in 1-Hexene Oligomerization and Structure of Metal Hydride Reaction Centers |
| title_full_unstemmed | Catalytic Properties of Zirconocene-Based Systems in 1-Hexene Oligomerization and Structure of Metal Hydride Reaction Centers |
| title_short | Catalytic Properties of Zirconocene-Based Systems in 1-Hexene Oligomerization and Structure of Metal Hydride Reaction Centers |
| title_sort | catalytic properties of zirconocene based systems in 1 hexene oligomerization and structure of metal hydride reaction centers |
| topic | zirconocenes metal hydrides methylaluminoxane perfluorophenyl borates alkene dimerization oligomerization |
| url | https://www.mdpi.com/1420-3049/28/6/2420 |
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