Lukešová, L., Ward, Benjamin David  ORCID: https://orcid.org/0000-0003-1406-5940, Bellemin-Laponnaz, S., Wadepohl, H. and Gade, L. H.
2007.
C-3-Symmetric chiral organolanthanide complexes: Synthesis, characterization, and stereospecific polymerization of alpha-olefins.
Organometallics
26
(18)
, pp. 4652-4657.
10.1021/om700504f
|
Abstract
The trialkyl complexes [M(iPr-trisox)(CH2SiMe2R)3] (R = Me, M = Y, (1), R = Ph, M = Lu (2a), R = Me, M = Lu (2b), Tm (3), Er (4), Ho (5), and Dy (6)) were prepared from 1,1,1-tris[(S)-4-isopropyloxazolinyl]ethane (iPr-trisox) and the corresponding trialkyl precursors [M(CH2SiMe2R)3(THF)n]. Their molecular structures all display a highly distorted octahedral geometry, with the angles subtended at the metal center significantly deviating from the ideal 90°, which is attributed to the steric demands imposed by the large CH2SiMe2R ligands, both with each other and with the isopropyl groups of the iPr-trisox ligand. Active catalysts for the polymerization of α-alkenes (n-hexene, n-heptene, and n-octene) were generated in situ by reaction of the trialkyl precatalyst with 2 equiv of trityl tetrakis(pentafluorophenyl)borate. In all cases polyolefins with Mw/Mn values of between 1.58 and 2.08 and isotacticities of 80−95% were obtained. The polymerization activity increases from lutetium to thulium and then subsequently decreases with increasing ionic radius of the metal due to a combination of activation with increasing ionic radius and decreasing catalyst stability.
| Item Type: | Article |
|---|---|
| Date Type: | Publication |
| Status: | Published |
| Schools: | Chemistry |
| Subjects: | Q Science > QD Chemistry |
| Publisher: | American Chemical Society |
| ISSN: | 0276-7333 |
| Last Modified: | 18 Oct 2022 12:24 |
| URI: | https://orca.cardiff.ac.uk/id/eprint/9725 |
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