STERICALLY CROWDED ARYLOXIDE COMPOUNDS OF ALUMINUM

The chemistry of aluminum compounds containing sterically demanding aryloxide ligands is presented. In particular, those of compounds derived from 2,6-di-tert-butyl-4-methylphenol (BHT-H, from the trivial name butylated hydroxytoluene). The synthesis and structure of three-coordinate monomeric derivatives, and their ligand exchange reactions, are discussed in comparison to the more typical four-coordinate oligomeric aluminum alkoxide and aryloxide compounds. The reactions of the sterically crowded aryloxide compounds is divided into four general classes: oxidation and hydrolysis, the formation of Lewis acid-base complexes, the reaction with organic carbonyls, and the reaction with main group halides. Alane-aryloxide compounds are discussed separately, as are the 1,3-diphenyltriazenide derivatives. Finally, a discussion of the Al-O bonding interactions in four-coordinate aluminum aryloxides is presented, giving spectroscopic and theoretical evidence for and against various postulates to explain the presence of short Al-O distances and large Al-O-C angles.