Aluminum Complexes Supported by Tridentate Aminophenoxide Ligand as Efficient Catalysts for Ring-Opening Polymerization of ε-Caprolactone

Abstract

Aluminum complexes bearing dianionic amine bis(phenolate) ligand are described. Reactions of ligand precursors H2O2NMe or H2O2NPr [H2O2NMe = (CH3)N-(CH2-2-HO-3,5-C6H2(tBu)2)2; H2O2NPr = (CH3CH2CH2)N-(CH2-2-HO-3,5-C6H2(tBu)2)2] with 1.1 mol equiv of AlMe3 in toluene afford MeAl(O2NMe) (1) and MeAl(O2NPr) (2) as four-coordinate aluminum methyl complexes. The molecular structures are reported for compounds 1 and 2. Both compounds show excellent catalytic activity toward the ring-opening polymerization of ε-caprolactone in the presence of benzyl alcohol.