Methoxyaryl substituted aluminum ketiminate complexes and its activity in ring opening polymerization processes

•Methoxyaryl substituted aluminum ketiminate complexes were prepared.•Reactivity of dimethylaluminum complex with diiodine was studied.•Ketimine reacts with lithium aluminum hydride to tri(ketiminate) aluminum complex.•Selected complexes promote ring opening polymerization processes.

The synthesis of dimethyl aluminum (LoAlMe2) and chloromethyl aluminum (LoAlMeCl) complexes containing ketiminate ligand [(2-MeO)C6H4]N(H)C(Me) = CHC(Me) = O (LoH) is reported along with the preparation of Lo3Al from LoH and LiAlH4, and ionic [Lo′Al(thf)3]I from LoAlMe2 and I2. In the later complex the pseudooctahedral geometry of the aluminum ion by terdentate ligand {[(2-O)C6H4]NC(Me) = CHC(Me) = O}2 − (Lo′), originated from Lo ligand by the methyl group abstraction, and three THF molecules are observed. Structures of these complexes were determined by X-ray techniques. The activity of LoAlMe2 and LoAlMeCl as initiators of ring opening polymerization of ε-caprolactone, trimethylene carbonate and l-lactide, and (co)polymerization of cyclohexene oxide and carbon dioxide was studied.

Graphical abstractFour aluminum(III) complexes containing bifunctional ketiminate ligand were synthesized and tested for catalytic activity in ring opening polymerization of lactone, carbonate and oxirane species.Figure optionsDownload full-size imageDownload as PowerPoint slide