title: Stereoselective ring-opening polymerization of racemic lactide using aluminum-achiral ligand complexes: exploration of a chain-end control mechanism.
abstract: Stereoselective polymerization of racemic lactide (rac-LA) was examined using Al-achiral ligand complexes. By introduction of substituents in aromatic rings of Schiff base ligands, a higher selectivity was obtained without any chiral auxiliaries in the catalyst via a chain-end control mechanism. The T(m) values (T(m) 170-192 degrees C) were comparable to or higher than that of homochiral polymer, poly(L-LA) (T(m) 162 degrees C), and a thermally more stable polylactide than poly(L-LA) was prepared from rac-LA.
authors.affiliation: Laboratory of Polymer Chemistry, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan. nnomura@agr.nagoya-u.ac.jp
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Nomura
authors.forename: Ryohei
authors.initials: R
authors.lastname: Ishii
authors.forename: Matsujiro
authors.initials: M
authors.lastname: Akakura
authors.forename: Keigo
authors.initials: K
authors.lastname: Aoi
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D001672:Biocompatible Materials / Q000138:chemical synthesis* / Q000737:chemistry; D001673:Biodegradation, Environmental; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry; D011091:Polyesters / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D001672:Biocompatible Materials; D008024:Ligands; D009942:Organometallic Compounds; D011091:Polyesters; C033616:poly(lactide); D000535:Aluminum