Abstract
The complexes l-[CMe2{CHMeN(2-Pri-C6H 4)}2TiCl2] (2) and u-[CMe2{CHMeN(2,6-Pr2iC6H3)} 2TiCl2] (3), C2- and Cs-symmetric analogues, respectively, of McConville's C2v hexene polymerization precatalyst [(CH2)3{N(2,6-Pr2i-C6H3)}2TiCl2] (1), were prepared by high-dilution salt-elimination from the lithium amides and characterized spectroscopically and crystallographically. Complex 2, though less active than 1, was a highly active catalyst of polymerization of 1-hexene when activated by MAO. Complex 3 was inactive under similar conditions. NMR analysis confirmed that there were more mmmm pentads in polymer produced by 2 than in the statistically atactic material produced by 1, though the isotacticity index was not high. The results are interpreted in terms of an isotactic/atactic block structure, caused by syn/anti fluxion of the two 2-isopropylphenyl rings in 2. Kinetic profiles and polydispersities were consistent with a slow initiation step involving monomer, followed by rapid propagation, with some chain transfer to aluminium and only a small extent of β-hydride elimination. The rubber-like polymers were indistinguishable by thermal analysis from those prepared by Ziegler-Natta catalyst systems. © 2005 Published by Elsevier B.V.
Original language | English |
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Pages (from-to) | 2078-2086 |
Number of pages | 8 |
Journal | Journal of Organometallic Chemistry |
Volume | 690 |
Issue number | 8 |
DOIs | |
Publication status | Published - 15 Apr 2005 |
Keywords
- Diamido ligands
- Polyhexen
- Titanium
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CCDC 251184: Experimental Crystal Structure Determination
Heatley, F. (Contributor), Mair, F. (Contributor), Pritchard, R. (Contributor) & Woods, R. J. (Contributor), Cambridge Crystallographic Data Centre, 1 Jan 2005
DOI: 10.5517/cc8fcqr, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/cc8fcqr&sid=DataCite
Dataset
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CCDC 251183: Experimental Crystal Structure Determination
Heatley, F. (Contributor), Mair, F. (Contributor), Pritchard, R. (Contributor) & Woods, R. J. (Contributor), Cambridge Crystallographic Data Centre, 1 Jan 2005
DOI: 10.5517/cc8fcpq, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/cc8fcpq&sid=DataCite
Dataset