A series of Al(III) compounds containing the C6F5-substituted beta-diketiminate ligands LAlMeCl (2), LAlMe2 (3), LAlMel (4), and LAlBr2 (5) (L = HC[(CMe)(NC6F5)](2)) were synthesized and characterized. The hydrolysis of 2 and 4 in the presence of 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene as the hydrogen halide acceptor both lead to (LAIMe)(2)(mu-O) (6), a methylalumoxane derivative, which is the first hydrolysis product with the general formula of (RAIMe)nO. A comparison of the hydrolysis products of 2 and 4 with that of L'AIMeCl (L' = HC[(CMe)(NAr)](2), Ar = 2,6-iPr(2)C(7)H(3)) shows that with the C6F5-substituted beta-diketiminate ligand, it was not possible to generate LAIMe(OH). This is obviously due to the stronger Bronsted acidity of the proton and the smaller size of the C6F5 group in this compound compared to that of the corresponding 2,6-iPr(2)C(6)H(3) derivative.