Synthesis and Characterization of -Diketiminate Aluminum Compounds and Their Use in the Ring-Opening Polymerization of epsilon-Caprolactone

Four aluminum alkyl compounds, [CH{(CH3)CN-2,4,6-MeC6H2}(2)AlMe2] (1), [CH{(CH3)CN-2,4,6-MeC6H2}(2)AlEt2] (2), [CH{(CH3)CN-2-iPrC(6)H(4)}(2)AlMe2] (3), and [CH{(CH3)CN-2-iPrC(6)H(4)}(2)AlEt2] (4), bearing -diketiminate ligands [CH{(Me)CN-2,4,6-MeC6H2}](2) ((LH)-H-1) and [CH{(Me)CN-2-(PrC6H4)-Pr-i}](2) ((LH)-H-2) were obtained from the reactions of trimethylaluminum, triethylaluminum with the corresponding -diketiminate, respectively. All compounds were characterized by H-1 NMR and C-13 NMR spectroscopy, single-crystal X-ray structural analysis, and elemental analysis. Compounds 1-4 were found to catalyze the ring-opening polymerization (ROP) of epsilon-caprolactone (epsilon-CL) with good activity.