The stronger the better: donor substituents push catalytic activity of molecular chromium olefin polymerization catalysts
The donor strength of bifunctional pyridine-cyclopentadienyl ligands was altered systematically by the introduction of donating groups in the para-position of the pyridine. In the resulting chromium complexes an almost linear correlation between donor strength and the nitrogen-chromium distance as w...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
2021
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| In: |
Chemistry - a European journal
Year: 2021, Volume: 27, Issue: 43, Pages: 11084-11093 |
| ISSN: | 1521-3765 |
| DOI: | 10.1002/chem.202101586 |
| Online Access: | Verlag, kostenfrei, Volltext: https://doi.org/10.1002/chem.202101586 Verlag, kostenfrei, Volltext: https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.202101586 
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| Author Notes: | Helge-Boj Hansen, Hubert Wadepohl, and Markus Enders |
| Summary: | The donor strength of bifunctional pyridine-cyclopentadienyl ligands was altered systematically by the introduction of donating groups in the para-position of the pyridine. In the resulting chromium complexes an almost linear correlation between donor strength and the nitrogen-chromium distance as well as the electronic absorption maximum is experimentally observed. The connection of electron-donating groups in the ligand backbone leads to an efficient transfer of the electronic influences to the catalytically active metal centre without restricting it through steric effects. Therefore, catalytic olefin polymerization activity, which is already very high for the previously studied catalysts, increase considerably by attaching para-amino groups to the chelating pyridine or quinoline, respectively. Combining electron-rich indenyl ligands with para-amino substituted pyridines lead to the highest catalytic activities observed so far for this class of organo chromium olefin polymerisation catalysts. The resulting polymers are of ultra-high molecular weight and the ability of the catalysts to incorporate co-monomers is also very high. |
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| Item Description: | First published: 21 May 2021 Gesehen am 24.11.2022 |
| Physical Description: | Online Resource |
| ISSN: | 1521-3765 |
| DOI: | 10.1002/chem.202101586 |