title: Ring-opening polymerization of cyclic esters with lithium amine-bis(phenolate) complexes.
abstract: Lithium compounds of tetradentate amino-bis(phenolato)-tetrahydrofuranyl ligands, Li(2)[L1] (1) and Li(2)[L2] (2) (where [L1] = 2-tetrahydrofuranyl-N,N-bis(2-methylene-4-methyl-6-tert-butylphenolate), and [L2] = 2-tetrahydrofuranyl-N,N-bis(2-methylene-4,6-tert-butylphenolate)) were characterized by multinuclear solution NMR and solid-state (6)Li and (7)Li NMR spectroscopy. The proligands, n-propylamino-N,N-bis(2-methylene-4-methyl-6-tert-butylphenol), (H(2)[L3]) and benzylamino-N,N-bis(2-methylene-4,6-di-tert-amylphenol), H(2)[L4] were reacted with n-butyllithium in THF to give the related dilithium compounds Li(2)[L3] (4) and Li(2)[L4] (5), respectively. The pyridine adduct of 1, (py)(2)Li(2)[L1] (3) and complexes 4 and 5 have been structurally characterized by single-crystal X-ray diffraction and NMR spectroscopy. The reactivity of these complexes for the ring-opening polymerization of rac-lactide, as well as the influences of monomer concentration, monomer/Li molar ratio, polymerization temperature and time, were studied.
authors.affiliation: Department of Chemistry, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X7, Canada.
authors.forename: Rebecca K
authors.initials: RK
authors.lastname: Dean
authors.forename: Amy M
authors.initials: AM
authors.lastname: Reckling
authors.forename: Hua
authors.initials: H
authors.lastname: Chen
authors.forename: Louise N
authors.initials: LN
authors.lastname: Dawe
authors.forename: Celine M
authors.initials: CM
authors.lastname: Schneider
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Kozak