Simple Generation of Cationic Aluminum Alkyls and Alkoxides Based on the Pendant Arm Tridentate Schiff Base

The prepared in situ methyl(chloro)aluminum complex (2) from Me2AlCl and the pendant arm tridentate Schiff base (H-SchNMe2) was used to generate the methylaluminum cationic species [(SchNMe2)AlMe]+ in further reaction with 1 equiv of AlCl3 or NaBPh4 as the chloride abstracting reagents. The exposure of the resulting methylaluminum cationic species to an excess of dry dioxygen at 0 degrees C afforded the alkoxyaluminum cationic species, [(SchNMe2)AlOMe]+ or [(SchNMe2)AlOPh]+. The alkoxylaluminum cations proved to be a very efficient catalyst in the polymerization of epsilon-caprolactone.