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Rare Earth Polymerization Catalysts Supported by Bulky Aminopyridinato Ligands
Author(s) -
Kempe Rhett
Publication year - 2010
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201000195
Subject(s) - chemistry , polymerization , ligand (biochemistry) , isoprene , alkyl , polymer chemistry , catalysis , hydride , coordination sphere , rare earth , ring opening polymerization , coordination polymerization , medicinal chemistry , polymer , copolymer , solution polymerization , organic chemistry , molecule , metal , receptor , biochemistry , mineralogy
The coordination and polymerization chemistry of molecular rare earth catalysts stabilized by bulky aminopyridinato (= Ap) ligands are reviewed. The selective synthesis of dialkyls allows the generation of rare earth alkyl hydride clusters and the generation of organo rare earth cations. These cations are able to catalyze polyethylene chain growing at aluminum and are able to polymerize isoprene stereoselectively. Complexes of the type [Ap Ln (thf) m X 2 ] ( X = Cl, Br; m = 2, 3) allow controlled ring opening polymerization of ϵ‐caprolactone in the presence of NaBH 4 . α,ω‐Dihydroxytelechelic polymers are obtained. Bis‐Ap alkyl complexes undergo C–H activation of one of the methyl groups of the Ap ligand. The rates of this activation reaction depend strongly from the nature of the “leaving” ligand and the radius of the rare earth ion that mediates C–H activation.