Structural modification of phenoxyimine titanium complexes and activation studies with alkylaluminum compounds
| Autor: | Yara van Ingen, Huaqin Yang, Sanjay Rastogi, Burgert Blom, Dario Romano |
|---|---|
| Přispěvatelé: | Biobased Materials, RS: FSE Biobased Materials, Maastricht Science Programme, RS: FSE MSP, Circular Chemical Engineering, RS: FSE AMIBM |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
UHMWPE
Alkylaluminum Methylaluminoxane Activation FI CATALYSTS GROUP IV CATALYST 010402 general chemistry POST-METALLOCENES 01 natural sciences Medicinal chemistry DFT Catalysis Inorganic Chemistry chemistry.chemical_compound Butylated hydroxytoluene Reactivity (chemistry) OLEFIN POLYMERIZATION CATALYSTS Physical and Theoretical Chemistry HOMO/LUMO Mulliken population analysis Alkyl chemistry.chemical_classification 010405 organic chemistry Ligand Organic Chemistry METHYLALUMOXANE PERFORMANCE ETHYLENE POLYMERIZATION 0104 chemical sciences IMINE CHELATE LIGANDS chemistry ZIRCONIUM COMPLEXES |
| Zdroj: | ChemCatChem, 12(20), 5209-5220. Wiley-VCH Verlag GmbH & CO. KGaA |
| ISSN: | 1867-3880 |
| Popis: | The synthesis and characterization of three complexes of the type (N‐(3‐tert‐butylsalicylidene)‐R)2TiCl2 [R=2,6‐difluorophenyl 1, R=2,6‐dimethylphenyl 2, R=phenyl 3] is reported and compared with the highly active R=2,3,4,5,6,–pentafluorophenyl 4. The complexes were tested for ethylene polymerization when activated with different co‐catalysts, giving high catalytic activity when activated with methylaluminoxane for complexes 3 and 4. Complex 3 is the only catalyst to be inactive when activated with diethylaluminum chloride. Unexpectedly, for complexes 1 and 2, no catalytic activity is recorded when butylated hydroxytoluene in methylaluminoxane is used to remove the trimethylaluminum, while the catalytic activity for complex 3 is retained. NMR study on the activation of the four complexes in the presence of common alkyl aluminum co‐catalysts suggests the formation of Ti(III) species in the presence of tri‐iso‐butylaluminum, and also the formation of NR−CH2 (R: −Al(CH2CH(CH3)2)2) bond from the N=C−H bond of the ligand explaining the absence of catalytic activity. Density functional theory calculations using B3LYP and a combination of basis sets (6‐31+G and cc‐pVTZ) were performed on the catalyst precursors and the activated species showing insights into the frontier orbitals, localizing the LUMO on the imino bond elucidating their reactivity. Mulliken charges are also reported and an unexpected relationship between the nitrogen on the ligands and the molecular weight is observed. |
| Databáze: | OpenAIRE |
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