title: Effects of ligand tuning on dinuclear indium catalysts for lactide polymerization.
abstract: Functionalized diaminophenols, H(N(R1R2)N(R3)O), were investigated as ligands for indium catalysts in the ring-opening polymerization of racemic lactide. Precursor complexes (N(Me2)N(Me)O)InCl(2) (1), (N(Pr2)NO)InCl(2) (2), and (N(Mes)NO)InCl(2) (3) were synthesized and fully characterized by (1)H and (13)C NMR spectroscopy, elemental analysis, and single-crystal X-ray crystallography. Complexes 1 and 2 were used to synthesize alkoxy-bridged complexes [(N(Me2)N(Me)O)InCl](2)(μ-Cl)(μ-OEt) (4) and [(N(Pr2)NO)InCl](2)(μ-Cl)(μ-OEt) (5). These complexes catalysed the polymerization of racemic lactide at different rates, with complex 5 being substantially more active than complex 4. The dissociation behaviour of these catalysts in the presence of lactide was also studied and used to make comparisons with previously reported catalyst systems.
authors.affiliation: University of British Columbia, Department of Chemistry, 2036 Main Mall, Vancouver, B.C., Canada.
authors.forename: Kimberly M
authors.initials: KM
authors.lastname: Osten
authors.forename: Insun
authors.initials: I
authors.lastname: Yu
authors.forename: Ian R
authors.initials: IR
authors.lastname: Duffy
authors.forename: Paraskevi O
authors.initials: PO
authors.lastname: Lagaditis
authors.forename: Joey C-C
authors.initials: JC
authors.lastname: Yu
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Wallis
authors.forename: Parisa
authors.initials: P
authors.lastname: Mehrkhodavandi
mesh_terms: D002384:Catalysis; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry; D018360:Crystallography, X-Ray; D004146:Dioxanes / Q000737:chemistry*; D007204:Indium / Q000737:chemistry*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D058105:Polymerization; D013237:Stereoisomerism
chemical_list: D056831:Coordination Complexes; D004146:Dioxanes; D008024:Ligands; D007204:Indium; C091880:dilactide