VERSATILITY IN PHENOLATE BONDING IN ORGANOALUMINUM COMPLEXES CONTAINING MONO-ORTHO-CHELATING AND BIS-ORTHO-CHELATING PHENOLATE LIGANDS - X-RAY STRUCTURES OF AL(OC6H2(CH(2)NME(2))(2)-2,6-ME-4)(3), 6H2(CH(2)NME(2))(2)-2,6-ME-4)CENTER-DOT-N-ALME(3), AND -2,6-ME-4)CENTER-DOT-N-ALME(3)CENTER-DOT-O-ALME(3)

The effect of intramolecular coordination on both the structure and th e Lewis acidity of aluminum phenolates has been studied. The mono-orth o-amino-substituted phenol HOC6H4(CH(2)NMe(2))-2 (3) reacts with AlMe( 3) to produce the substitution products AlMe(3-x), (OC6H4(CH(2)NMe(2)) -2)(x) (x = 1 (la), 2 (Ib), and 3 (Ic)) and the trimethylaluminum addu ct AlMe(2)(OC6H4(CH(2)NMe(2))-2). O-AlMe(3) (Id), all in high yield. F or the bis-ortho-amino-substituted phenol HOC6H2(CH(2)NMe(2))(2)-2,6-M e-4 (4) the substitution products AlMe(3-x) (OC6H2(CH(2)NMe(2))(2)-2,6 -Me-4)(x) (x = 2 (2b) and 3 (2c)) were obtained, as well as the mono- and bis(trimethylaluminum) adducts AlMe(2)(OC6H2(CH(2)NMe(2))2-2,6-Me- 4). N-AlMe(3) (2d) and AlMe(2)(OC6H2(CH(2)NMe(2))2-2,6-Me-4). N-AlMe(3 ) . O-AlMe(3) (2e). The mono(phenolate) dimethylaluminum complexes (la and 2a) easily undergo an inter- (la) or an intramolecular (2a) Lewis base induced ligand exchange to give the bis(phenolate) complexes (Ib and 2b, respectively) and trimethylaluminum. The aluminum phenolate c omplexes were characterized by variable-temperature NMR and single-cry stal structure determinations (2c-e). The solid state structure of 2c contains the aluminum surrounded by two bidentate, O,N-bonded, phenola te ligands and one monodentate, O-bonded, phenolate ligand in a trigon al bipyramidal coordination geometry, with the oxygen atoms in the tri gonal plane and the two coordinating nitrogen atoms in the apical posi tions. The molecular structure of 2d contains one AlMe(2) moiety which is bidentate, O,N-coordinated by the phenolate ligand, in a distorted tetrahedral geometry. The second amino substituent forms a Lewis acid -base complex with a molecule AlMe(3), also with a distorted tetrahedr al geometry around the aluminum. The structure of 2e is similar to tha t of 2d but contains an additional molecule of AlMe(3), which forms a Lewis acid-base complex with a lone pair of the phenolate oxygen atom, resulting in a distorted tetrahedral geometry around the aluminum. NM R spectroscopy shows the solution structures to be closely related to those established in the solid state.