Studies of the Ligand Effect on the Synthesis of Dialuminoxanes by Various beta-Diketiminato Ligands

Abstract

Reactions of LH (L = HC[C(Me)N(2,6-Me2C6H3)](2)) with MenAlCl3-n, in diethyl ether afforded the adducts LH center dot AlMen(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 LAlMeC1 (2) with equimolar amounts of water in the presence of N-heterocyclic carbene (NHC) gave a mixture of [LAl(Me)](2)(mu-O) (7) and dimeric [LAlMe(mu-OH)](2) (8). A convenient route for the preparation of [LAlMe(mu-OH)](2) (8) was the NHC-assisted controlled hydrolysis of LAlMeI (9). Stepwise hydrolysis of LAlH2 (11) gave dialuminoxane hydride [LAl(H)](2)(mu-O) (12) and dialuminoxane hydroxide [LAl(OH)](2)(mu-O) (13), respectively. Anhydrous treatment of LAlCl2 (1) or LAlMeCl (2) with Ag2O afforded chlorinated dialuminoxane [LAl(Cl)](2)(mu-O) (14) and [LAl(Me)](2)(mu-O) (7), respectively.