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Evaluation of the activity of samarium(III) complexes with L-aspartic acid, L-glutamic acid, glycine and orto-phenanthroline, as initiators in the polymerization of cyclic carbonates

Abstract:

Catalytic behavior of samarium(III) acetate (SmOAc) and amino acid complexes of samarium(III) tipe: Sm(ophen)( Ln)3 (o-phen = orto-phenantroline, L1 = L-aspartic acid; L2= L-glutamic acid y L3 = glicine) in polymerization of cyclic carbonates: trimethylene carbonate (TMC), 1-methyltrimethylene carbonate (MTMC) and 2,2-dimethyl- 1,3-trimethylene carbonate (DMTC), was studied. It was found that the catalytic activity of the initiators used is influenced by the structure of amino acid bond at samarium(III) atom. The polymers were characterized by nuclear magnetic resonance and size exclusion chromatography. Based on the 1H-NMR it was proposed a coordination- insertion mechanism for the polymerization with selective rupture of acyl-oxygen bond.