Synthesis and X-ray crystal structure of dichloro[S-1-phenyl-N-(S-pyrrolidin-2-ylmethyl)ethanamine]zinc(II) and its catalytic application to rac-lactide polymerization

New dichloro zinc(II) complex ligated by the homochiral bidentate ligand S-1-phenyl-N-(S-pyrrolidin-2-ylmethyl)ethanamine (PPMA) was synthesized and characterized by X-ray crystallography. The geometry of the (PPMA)ZnCl₂ is a distorted tetrahedron comprising of zinc metal as a center linked with two N atoms of the PPMA in a bidentate coordination mode along with two chloro ligands. The catalytic capacity of the complex was evaluated in ring opening polymerization (ROP) of rac-lactide. The active catalyst species was generated in situ by treating MeLi to complex (PPMA)ZnCl₂. The dimethyl derivative of the (PPMA)ZnCl₂ showed highly activity in ROP of rac-lactide and gave preference to heterotactic polylactide.