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Ring‐opening polymerization of lactides using heterobimetallic yttrocene complexes
Author(s) -
Beckerle Klaus,
Hultzsch Kai C.,
Okuda Jun
Publication year - 1999
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(19990701)200:7<1702::aid-macp1702>3.0.co;2-2
Subject(s) - racemization , polymer chemistry , polymerization , ring opening polymerization , lactide , copolymer , transesterification , chemistry , enantiomer , catalysis , polymer , organic chemistry
Structurally characterized, chiral heterobimetallic yttrocene derivatives Li[Y(η 5 : η 1 ‐C 5 R 4 SiMe 2 NCH 2 CH 2 OMe) 2 ] (R = Me, H) have been shown to be active in the controlled ring‐opening polymerization of L‐lactide to give poly( L ‐lactide)s with high molecular weights and moderately narrow molecular weight distributions ( M w / M n < 1.50). Both transesterification and racemization appear to be less prominent. 1 H NMR spectroscopic tetrad analysis of copolymers prepared using a mixture of L ‐ and D ‐lactide demonstrates the absence of any preference for one enantiomer during the polymerization.