title: Highly active chromium(III) complexes based on tridentate pyrazolyl pyridyl ligands for ethylene polymerization and oligomerization.
abstract: A set of new chromium(III) [Cr(III)] complexes based on the tridentate ligand HC(Pz)2Py (Pz = pyrazole; Py = pyridine) and its derivatives were prepared, characterized, and evaluated for ethylene polymerization/oligomerization. X-ray single-crystal analyses of the Cr(III) complexes showed tridentate coordination on the fac-octahedral Cr sphere. Upon activation with methylaluminoxane (MAO), the precatalysts and the ligands L1-L3 mixed in situ with Cr(acac)3 were highly active and generally produced polyethylene as a major product. Their catalytic performances were markedly affected by the substituents on the methine carbon atom of the ligands and reaction conditions.
authors.affiliation: Department of Chemistry, Chungnam National University, Daejeon 305-764, Korea.
authors.forename: Jong-Eun
authors.initials: JE
authors.lastname: Park
authors.forename: Sung Kwon
authors.initials: SK
authors.lastname: Kang
authors.forename: Jeong Oh
authors.initials: JO
authors.lastname: Woo
authors.forename: Kyung-sun
authors.initials: KS
authors.lastname: Son