Effects of the Linking of Cyclopentadienyl and Ketimide Ligands in Titanium Half-sandwich Olefin Polymerization Catalysts

0474115 - ÚFCH JH 2018 RIV DE eng J - Journal Article
Varga, Vojtěch - Večeřa, M. - Gyepes, R. - Pinkas, Jiří - Horáček, Michal - Merna, J. - Lamač, Martin
Effects of the Linking of Cyclopentadienyl and Ketimide Ligands in Titanium Half-sandwich Olefin Polymerization Catalysts.
ChemCatChem. Roč. 9, č. 16 (2017), s. 3160-3172. ISSN 1867-3880. E-ISSN 1867-3899
R&D Projects: GA ČR(CZ) GA14-08531S; GA ČR(CZ) GA17-13778S
Institutional support: RVO:61388955
Keywords : ketimide ligands * olefin polymerization catalysts * cyclopentadienyl
OECD category: Polymer science
Impact factor: 4.674, year: 2017

The role of the ketimide ligand geometry in Ti half-sandwich complexes and the consequent effects in olefin polymerization catalysis (ethylene, styrene, 1-hexene polymerization, and ethylene/1-hexene copolymerization) were investigated under various conditions. [CpTiCl2(N=CtBu(2))] (1, Cp = eta(5)-cyclopentadienyl) was used as a reference compound for comparison with the recently described complex [{eta(5)-C5H4CMe2CMe2C(tBu)=N-kN}TiCl2] (2a) and a new derivative that has a longer linker between Cp and the ketimide, [{eta(5)-C5H4CH2CH2CMe2C(tBu)=N-kN}TiCl2] (9). The presence of a distorted intramolecularly tethered ketimide moiety reduces the polymerization activity significantly in systems that contain Al-based cocatalysts (methylaluminoxane, triisobutylaluminum). However, in Al-free systems both types of compounds provided active polymerization catalysts. Notably, the recently reported activation system Et3SiH/B(C6F5)(3) was for the first time demonstrated to activate Ti complexes for ethylene and 1-hexene (co)polymerization catalysis by hydride transfer.
Permanent Link: http://hdl.handle.net/11104/0271232