Di‐ and trivalent rare earth complexes stabilized by sterically demanding aminopyridinato ligands as initiators in ring‐opening polymerization reactions of ϵ‐caprolactone |
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| Authors: | Michèle Schappacher Natalie M Scott Rhett Kempe |
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| Institution: | 1. Laboratoire de Chimie des Polymères Organiques, CNRS‐ENSCPB‐Université Bordeaux 1, ENSCPB, 16 Avenue Pey‐Berland, 33607 Pessac Cedex, France;2. Lehrstuhl für Anorganische Chemie II, Universit?t Bayreuth, 95440 Bayreuth, Germany |
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| Abstract: | Salt elimination protocols using Ap*K {Ap*H = (2,6‐diisopropyl‐phenyl)‐6‐(2,4,6‐triisopropyl‐phenyl)‐pyridin‐2‐yl]‐amine} lead to the rare earth aminopyridinato complex Ap*LuCl2(thf)2], 4 . Results of X‐ray crystal structure analyses of 4 and the corresponding single THF coordinated dimer are discussed. Ring‐opening polymerization of ε‐caprolactone initiated by complexes Ap*LaBr2(thf)3], 2 , Ap*YbI(thf)2]2, 3 or 4 in the presence of NaBH4 allows the preparation, in a short reaction time, of α,ω‐dihydroxytelechelic polymers with high molar mass (  up to 50,000) and moderate molar mass distributions (1.3 <  / < 1.6). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3611–3619, 2007 |
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| Keywords: | aminopyridinato ligands borohydride catalysts polyesters rare earth ring‐opening polymerization synthesis |
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