Author(s)

Pascal Binda^1*, Kimberly Rivers¹, Clifford Padgett²

¹Department of Chemistry and Forensic Science, Savannah State University, Savannah, GA, USA.
²Department of Chemistry and Physics, Armstrong State University, Savannah, GA, USA.

The syntheses of a library of new chiral aminophenolate bidentate O,N-type ligands HOC₆H₄(2-R- 4-R′)CH₂N(Me)CH(Me)C₆H₅ [R = R′ = Bu^t, 1; R = R′ = Pent, 2; R = Bu^t, R′ = Me, 3; R = Me, R′ = Bu^t, 4; R = R′ = Me, 5] and tridentate O,N,O-type ligands HOC₆H₄(2,4-Bu^t)CH = NCH(R′′)C₆H₅ [R′′ = Me, 6; R′′ = CH₂OMe, 7] are reported. These ligands were characterized by elemental analysis, nuclear magnetic resonance spectroscopy (¹H & ¹³C), and single crystal X-ray diffraction. These ligands serve as chiral auxiliaries for inorganic chemists to design chiral metal-based complexes for asymmetric catalysis and stereoselective polymerization reactions. Three new heteroleptic zinc complexes based on these ligands have been synthesized in moderate yields via a ligand-exchange transamination reaction between homoleptic [Zn(N(SiMe₃)₂)₂] and one equivalent of corresponding ligands to afford [L³ZnN- (SiMe₃)₂] (3a), [L⁴ZnN(SiMe₃)₂] (4a), and [L⁷ZnN(SiMe₃)₂] (7a). Solvent-free polymerization of raclactide at 130°C using these zinc compounds yielded atactic polylactides with Mw 10,000 g/mol and narrow polydispersity of 1.3.

Chiral Ligands, Aminophenolate, Zinc, Lactide, Polymerization

Binda, P. , Rivers, K. and Padgett, C. (2016) Zinc Complexes of New Chiral Aminophenolate Ligands: Synthesis, Characterization and Reactivity toward Lactide. Open Journal of Inorganic Chemistry, 6, 205-218. doi: 10.4236/ojic.2016.63016.