The Selective Preparation of an Aluminum Oxide and Its Isomeric C−H-Activated Hydroxide

An aluminum oxide [LAlO]₂ (1) has been prepared by the oxidative addition of aluminum(I) monomer LAl (L = HC[(CMe)(NAr)]₂, Ar = 2,6-iPr₂C₆H₃) with molecular oxygen. The short Al−O bonds in Al₂(μ-O)₂ result in short Al···Al contacts and subsequent steric crowding of the Ar substituents from the two oriented L. 1 hydrolyzes to form [LAl(OH)]₂(μ-O) (2). A C−H-activated aluminum hydroxide 4, an isomer of 1, however, is obtained by hydrolysis of the bulky aluminum amide 3 rather than by a conversion by high temperature treatment of 1. This indicates selective preparation of isomers 1 and 4.