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Polymerization of ϵ‐caprolactone using heterobimetallic lanthanocene complexes
Author(s) -
Hultzsch Kai C.,
Okuda Jun
Publication year - 1997
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.1997.030180909
Subject(s) - monomer , polymerization , caprolactone , dispersity , polymer chemistry , polymer , chemistry , ring opening polymerization , molar mass distribution , organic chemistry
The chiral heterobimetallic complexes Li[Ln(η 5 : η 1 ‐C 5 R 4 1 SiMe 2 NCH 2 CH 2 R 2 ) 2 ] (Ln = Y, Lu; C 5 R 4 1 = C 5 Me 4 , C 5 H 4 , 3‐C 5 H 3 t Bu; R 2 = OMe, NMe 2 ; Me: methyl; t Bu: tert ‐butyl) have been found to polymerize ϵ‐caprolactone to give a polymer of high molecular weight ( M̄ n < 20 000) and moderate polydispersity ( M̄ w / M̄ n < 2.0). Failure to observe a correlation between monomer/initiator ratio and molecular weight suggests a polymerization mechanism different from a pseudo‐anionic mechanism.