title: Polyamine-stabilized sodium aryloxides: simple initiators for the ring-opening polymerization of rac-lactide.
abstract: Metalation of 2,4,6-tri(methyl)phenol ((Me)ArOH) and 2,6-di(tert-butyl)-4-methylphenol ((Bu)ArOH) with NaN(SiMe(3))(2) in toluene and in the presence of stoichiometric amounts of the polydentate amines N,N,N',N'-tetramethylethylenediamine (TMEDA) and N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA) affords three new sodium aryloxide complexes [Na(μ-OAr(Bu))(TMEDA)](2) (3), [Na(μ-OAr(Me))(PMDETA)](2) (4), and [Na(OAr(Bu))(PMDETA)] (5). Complexes 3 to 5 have been isolated as crystalline materials in reasonable yields and characterized in the solid state by X-ray crystallography and in solution by NMR spectroscopy. Complexes 3 to 5 and the related [tris(2-dimethylaminoethyl)amine] (Me(6)TREN) derivatives [Na(OAr(Me))(HOAr(Me))(Me(6)TREN)] (1) and [Na(OAr(Bu))(Me(6)TREN)] (2), recently prepared in our group, are shown to be active as initiators for the ring-opening polymerization (ROP) of rac-lactide with benzyl alcohol as a co-initiator. However, during the course of the polymerization reactions intrachain and stereorandom transesterification side-reactions were observed under some of the experimental conditions tested.
authors.affiliation: Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Calvo
authors.forename: Matthew G
authors.initials: MG
authors.lastname: Davidson
authors.forename: Daniel
authors.initials: D
authors.lastname: García-Vivó
mesh_terms: D004146:Dioxanes / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D011073:Polyamines / Q000737:chemistry*; D011091:Polyesters / Q000138:chemical synthesis* / Q000737:chemistry; D058105:Polymerization; D012964:Sodium / Q000737:chemistry*
chemical_list: D004146:Dioxanes; D009942:Organometallic Compounds; D010087:Oxides; D011073:Polyamines; D011091:Polyesters; C033616:poly(lactide); C091880:dilactide; D012964:Sodium