Group IV complexes of an amine bis(phenolate) ligand featuring a THF sidearm donor: from highly active to living polymerization catalysts of 1-hexene

A new amine bis(phenolate) ligand bearing a THF donor on a sidearm and several dialkyl complexes of the group IV triad are introduced. The crystal structures of a zirconium dibenzyl complex and a titanium dibenzyl complex were solved, and revealed a strong binding of the oxygen donor of the THF grou...

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Bibliographic Details
Published in:Inorganica Chimica Acta Vol. 345; pp. 137 - 144
Main Authors: Groysman, Stanislav, Goldberg, Israel, Kol, Moshe, Genizi, Elisheva, Goldschmidt, Zeev
Format: Journal Article
Language:English
Published: Elsevier B.V 10-03-2003
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Summary:A new amine bis(phenolate) ligand bearing a THF donor on a sidearm and several dialkyl complexes of the group IV triad are introduced. The crystal structures of a zirconium dibenzyl complex and a titanium dibenzyl complex were solved, and revealed a strong binding of the oxygen donor of the THF group to the metal center. Upon activation with tris(pentafluorophenyl)borane the zirconium and the hafnium dibenzyl complexes lead to highly active 1-hexene polymerization catalysts. In comparison, titanium complexes (a dibenzyl complex and a dimethyl complex) lead to slower but living polymerization of 1-hexene at room temperature. Polymerization of neat 1-hexene under high dilution conditions was found to be living for an exceptionally long time of 6 days, leading to poly(1-hexene) of M w=816 000 and PDI=1.09. A block copolymerization of 1-hexene and 1-octene at room temperature could be obtained using the titanium catalysts. Zirconium, hafnium, and titanium complexes of an amine bis(phenolate) ligand bearing a THF donor on a sidearm were synthesized. Upon activation with tris(pentafluorophenyl) borane the zirconium and hafnium complexes lead to highly active 1-hexene polymerization catalysts, whereas the titanium catalysts leads to ‘immortal’ polymerization of 1-hexene, enabling the synthesis of exceptionally high molecular weight poly(1-hexene).
ISSN:0020-1693
1873-3255
DOI:10.1016/S0020-1693(02)01306-3