Zinc complexes bearing N,N′-bidentate entiopure ligands: Synthesis, structure and catalytic activity toward ring opening polymerisation of rac-lactide

Dichloro zinc complexes with (S)-1-phenyl-N-[(S)-1-(pyridin-2-yl)ethyl] ethanamine (PMMA) and (S)-1-(6-methylpyridin-2-yl)-N-[(S)-1-phenylethyl] ethanamine (MPMMA) were prepared and characterised by X-ray diffraction. The catalytic activity of the dimethyl complexes, generated in situ, was high in the ring opening polymerization of rac-lactide. Specifically, the dimethyl derivative of (PMMA)ZnCl₂ yielded a highly stereocontrolled polylactide with P_r = 0.84.