1522098-74-3Relevant academic research and scientific papers
Living ring-opening homo- and copolymerisation of ε-caprolactone and l-lactide by cyclic β-ketiminato aluminium complexes
Liu, Yan,Dong, Wei-Shi,Liu, Jing-Yu,Li, Yue-Sheng
, p. 2244 - 2251 (2014)
A series of novel aluminium complexes containing cyclic β-ketiminato ligands of type Me2Al{O-[(ArNCHC4H4(C 6H4))]} (3a, Ar = 2,6-iPr2C 6H3; 3b, Ar = C6H5; 3c, Ar = C 6F5) have been prepared in high yields. These complexes were identified by 1H, 13C NMR spectroscopy and elemental analysis. X-ray structural analyses for 3a-c revealed that these complexes have a distorted tetrahedral geometry around Al, and both bond distances and bond angles were considerably influenced by the ligand structure. These complexes were tested as catalyst precursors for ring-opening polymerisation of ε-caprolactone (ε-CL) and l-lactide (l-LA) in the presence of 2-propanol as an initiator. Complex 3a could polymerize ε-CL in a controlled manner with high efficiency. Based on the living characteristics, the preparation of well-defined block copolymers PCL-b-PLLA via sequential addition of monomers was performed by 3a. Note that complex 3c exhibited rather high catalytic activity for the ROP of l-LA with narrow molecular weight distribution. The monomer conversion reached completion only in 4 h when the l-LA/Al molar ratio was 100 at 80 °C. PLLA-b-PCL copolymers were thus easily produced by 3c.
