Polyolefin structural control using phenoxy-imine ligated group 4 transition metal complex catalysts

• Published in: e-Polymers Vol. 3; no. 1; pp. 258 - 282
• Main Authors: Matsukawa, Naoto, Ishii, Sei-ichi, Furuyama, Rieko, Saito, Junji, Mitani, Makoto, Makio, Haruyuki, Tanaka, Hidetsugu, Fujita, Terunori
• Format: Journal Article
• Language: English
• Published: De Gruyter 01.12.2003
• ISSN: 2197-4586; 1618-7229; 1618-7229
• DOI: 10.1515/epoly.2003.3.1.258

This paper describes the structural control of polyolefins achieved by using group 4 transition metal complex catalysts featuring a pair of phenoxy-imine chelate ligands (named FI catalysts). FI catalysts can produce very low to ultrahigh molecular weight polymers. For example, a Zr-FI catalyst bearing a cycloalkyl group on the imine-nitrogen with methylaluminoxane (MAO) activation is capable of selectively forming vinyl-terminated low molecular weight polyethylenes (M < 5000) whereas a Zr-FI catalyst with a triethylsilyl group ortho to the phenoxyoxygen can generate ethylene/propylene amorphous copolymers with ultra-high molecular weights (M > 10 000 000) when treated with Bu Al / Ph CB(C . In addition, a Ti-FI catalyst, possessing an o-phenoxytrimethylsilyl group, with MAO can form highly syndiotactic polypropylenes ([rrrr] = 84%, T = 140°C) via a chainend control mechanism. Conversely, upon activation with Bu Al / Ph CB(C , a Hf-FI catalyst with a tert-butyl group ortho to the phenoxy-oxygen is able to produce high molecular weight isotactic polypropylenes ([mm] = 69%, T = 124°C, M = 412 000) via a site control mechanism. Therefore, FI catalysts have shown the ability to create various polyolefin architectures by simple variation of the central metal, the ligand structure and the co-catalyst.