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 Pr = 0.84.

Graphical abstractNovel dichloro zinc complexes bearing homochiral pyridyl amine derivatives, after methylation at the zinc atom, were assessed for the ROP of rac-LA, yielding highly stereoselective PLA with Pr up to 0.84.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Pyridyl amine based dichloro Zn(II) complexes as catalyst precursors. ► Dimethyl derivatives proved to be highly stereoselective towards the ROP of rac-lactide. ► Living polymerization with a maximum heterotacticity up to 0.84.