TY - JOUR
T1 - Cobalt(II) complexes supported by iminomethylpyridine derived ligands
T2 - Synthesis, characterization and catalytic application towards methyl methacrylate and rac-lactide polymerisations
AU - Lee, Jaegyeong
AU - Kim, Kyeonghun
AU - Lee, Hyosun
AU - Nayab, Saira
N1 - Publisher Copyright:
© 2020
PY - 2021/3/1
Y1 - 2021/3/1
N2 - A series of cobalt(II) complexes, [LnCoCl2] (Ln = LA – LF), supported by iminomethylpyridine derivatives have been synthesized. The crystal structures of [LACoCl2], [LDCoCl2] and [LECoCl2] were identified by X-ray diffraction studies and they showed five-coordinated distorted square pyramidal geometries. All the complexes synthesized were evaluated as potential mediators for the coordination polymerisation of methyl methacrylate (MMA), in the presence of modified methylaluminoxane (MMAO). The Co(II) complex with the ligand (E)-N1,N1-dimethyl-N3-(pyridin-2-ylmethylene)propane-1,3-diamine displayed the highest catalytic activity (4.48 × 104 g PMMA / mol Co h) for MMA polymerisation. Regardless of the ligand architecture, syndio-enriched poly(methyl methacrylate) (PMMAs) with high molecular weights (11.1 × 105 g/mol) have been furnished. Additionally, the in situ generated dimethyl Co(II) complexes polymerized racemic-lactide (rac-LA), yielding hetero-enriched polylactide (PLA). Importantly, the stereoselectivities of the Co(II) complexes towards PLA have been found to be influenced by the steric and electronic properties of the amine substituents.
AB - A series of cobalt(II) complexes, [LnCoCl2] (Ln = LA – LF), supported by iminomethylpyridine derivatives have been synthesized. The crystal structures of [LACoCl2], [LDCoCl2] and [LECoCl2] were identified by X-ray diffraction studies and they showed five-coordinated distorted square pyramidal geometries. All the complexes synthesized were evaluated as potential mediators for the coordination polymerisation of methyl methacrylate (MMA), in the presence of modified methylaluminoxane (MMAO). The Co(II) complex with the ligand (E)-N1,N1-dimethyl-N3-(pyridin-2-ylmethylene)propane-1,3-diamine displayed the highest catalytic activity (4.48 × 104 g PMMA / mol Co h) for MMA polymerisation. Regardless of the ligand architecture, syndio-enriched poly(methyl methacrylate) (PMMAs) with high molecular weights (11.1 × 105 g/mol) have been furnished. Additionally, the in situ generated dimethyl Co(II) complexes polymerized racemic-lactide (rac-LA), yielding hetero-enriched polylactide (PLA). Importantly, the stereoselectivities of the Co(II) complexes towards PLA have been found to be influenced by the steric and electronic properties of the amine substituents.
KW - Cobalt(II) complexes
KW - Iminomethylpyridine
KW - Methyl methacrylate
KW - Polymerization
KW - Raclactide
UR - http://www.scopus.com/inward/record.url?scp=85099219351&partnerID=8YFLogxK
U2 - 10.1016/j.poly.2020.115003
DO - 10.1016/j.poly.2020.115003
M3 - Article
AN - SCOPUS:85099219351
SN - 0277-5387
VL - 196
JO - Polyhedron
JF - Polyhedron
M1 - 115003
ER -