Five tin(II) complexes bearing N2O2 bis(phenoxy)-amine as supporting ligands were successfully synthesized and characterized. The complexes were designed to have different steric and electronic contributions at the metal center with the aim to understand the catalyst’s structural effect toward the polymerization rates. The catalysts were characterized by 1H, 13C NMR spectroscopy, elemental analysis, and single-crystal X-ray crystallography. The studies of their solid-state structures reveal that all tin(II) complexes have a monomeric four-coordinate tin center. The position of the lone-pair electrons is clearly evidenced. The polymerizations of L-lactide were carried out under solvent-free polymerization at 120 °C. Interestingly, the cyclic poly(L-lactide) was obtained with narrow dispersity (1.12-1.28) when alcohol was absent during the polymerization. Polymerization of rac-lactide gave mostly atactic polymer.

Synthesis and characterization of tin (II) complexes supported by N2O2 bis(phenoxy)-amine ligands for the ring-opening polymerization of lactide

253rd National Meeting (2017)

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