Studies of the ligand effect on the synthesis of dialuminoxanes by various β-diketiminato ligands.

Reactions of LH (L = HCC(Me)N(2,6-Me(2)C(6)H(3))) with Me(n)AlCl(3-n) in diethyl ether afforded the adducts LH·AlMe(n)(Cl)(3-n) (n = 2, 3; 1, 4; 0, 5) in good yields. Treatment of 3 at elevated temperatures in toluene resulted in LAlMeCl (2) by intramolecular elimination of methane. The controlled hydrolysis of LAlMeCl (2) with equimolar amounts of water in the presence of N-heterocyclic carbene (NHC) gave a mixture of LAl(Me)(μ-O) (7) and dimeric LAlMe(μ-OH) (8). A convenient route for the preparation of LAlMe(μ-OH) (8) was the NHC-assisted controlled hydrolysis of LAlMeI (9). Stepwise hydrolysis of LAlH(2) (11) gave dialuminoxane hydride LAl(H)(μ-O) (12) and dialuminoxane hydroxide LAl(OH)(μ-O) (13), respectively. Anhydrous treatment of LAlCl(2) (1) or LAlMeCl (2) with Ag(2)O afforded chlorinated dialuminoxane LAl(Cl)(μ-O) (14) and LAl(Me)(μ-O) (7), respectively.