Synthesis, Structure, and Reactivity of a Superbulky Low-Valent β-Diketiminate Al(I) Complex

Low-valent β-diketiminate Al(I) complexes are generally synthesized in low yields (<20%). This is due to an intermolecular decomposition reaction. A new β-diketiminate Al(I) complex with a very bulky β-diketiminate ligand DIPePBDI was obtained in a high yield (81%) and the raw product was found to be essentially pure (DIPePBDI = HC[C(Me)N(DIPeP)]2; DIPeP = 2,6-C(H)Et2-phenyl). The crystal structure of (DIPePBDI)Al shows a monomeric complex. The reaction of (DIPePBDI)Al with AlBr3 gave (DIPePBDI)AlBr2 and Al(0). The reaction of (DIPePBDI)Al with KCH(SiMe3)2 led to deprotonation of a backbone Me group and formation of a K aluminyl complex. A minor side-product in which the BDI ligand was cleaved is also described. The very high yield of (DIPePBDI)Al makes it a welcome addition to the family of β-diketiminate Al(I) complexes.