Two Fe(II) complexes bearing chelating monoanionic [N,N]- pyridylamido ligands with bulky 2,6-dialkylphenyl substituents at both the amido and the ortho-pyridine moieties were synthesized and characterized. Single crystal X-ray diffraction analysis confirmed the formation of heteroleptic mononuclear [N,N]FeIIN(SiMe3)2 threecoordinated complexes. The two complexes were tested as catalysts for the Ring Opening Polymerization (ROP) of L-lactide (L -LA) and epsilon-caprolactone (CL) in the presence of 1 equiv. of alcohol co-initiator, resulting in high activity under both mild conditions (in solution at room temperature and low monomer/catalyst ratio) and more industrially relevant conditions (higher temperature and high monomer/catalyst ratio). The high activity and living character of the Fe(II) catalysts allowed the synthesis of stereo-multiblock polylactides by one-pot sequential addition of L -LA, D -LA and rac-LA at room temperature and in short reaction times, as well as the synthesis of di -block PCL-b-PLLA and three-block PLLA-b-PCL-b-PLLA copolymers by a similar approach.

New highly active Fe(II) pyridylamido catalysts for the ring opening polymerization and copolymerization of cyclic esters

Gravina G.
Investigation
;
Pierri G.
Investigation
;
Pellecchia C.
Writing – Review & Editing
2024-01-01

Abstract

Two Fe(II) complexes bearing chelating monoanionic [N,N]- pyridylamido ligands with bulky 2,6-dialkylphenyl substituents at both the amido and the ortho-pyridine moieties were synthesized and characterized. Single crystal X-ray diffraction analysis confirmed the formation of heteroleptic mononuclear [N,N]FeIIN(SiMe3)2 threecoordinated complexes. The two complexes were tested as catalysts for the Ring Opening Polymerization (ROP) of L-lactide (L -LA) and epsilon-caprolactone (CL) in the presence of 1 equiv. of alcohol co-initiator, resulting in high activity under both mild conditions (in solution at room temperature and low monomer/catalyst ratio) and more industrially relevant conditions (higher temperature and high monomer/catalyst ratio). The high activity and living character of the Fe(II) catalysts allowed the synthesis of stereo-multiblock polylactides by one-pot sequential addition of L -LA, D -LA and rac-LA at room temperature and in short reaction times, as well as the synthesis of di -block PCL-b-PLLA and three-block PLLA-b-PCL-b-PLLA copolymers by a similar approach.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11386/4888533
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