The Al-Cl bond lengths in compound 3 are shorter
than those of compound 4, while the ligand bite
(N1-Al1-N2) in 3 (av 81.09) is slightly bigger than that
in 4 (80.04(5)). The Al-Cl distances in 3 (av 2.129 A˚ ) are
quite similar to those observed in the mono 1-aza-allyl
complex [N(SiMe3)C(Ph)C(SiMe3)2]AlCl2 (av 2.071 A˚ ),
but the core angle is significantly different because of non
equivalent chelating backbone.13