Bimetallic Aluminum and Gallium Chelates with N₂O₂Ligands

A wide range of bimetallic aluminum molecules are formed in combinations between Salen Schiff base ligands and either AlR3 or AlR2Cl. They are of the general formulas L(AlR2)(2) and L(AlRCl)(2) with R = alkyl and L = Salen(Bu-t) ligand with relatively unusual "backbone" connections between the nitrogen atoms, 1,2-cyclohexylene (Salcen(Bu-t)), 1,4-butylene (Salben(Bu-t)), 1,5-pentylene (Salpten(Bu-t)), 1,6-hexylene (Salhen(Bu-t)), and 1,4-phenylene (1,4-Salophen(Bu-t)). Additionally, previously unknown ligands were employed with the "backbones" 1,4-bis(p-aminobenzyl)benzene (Salmaben(Bu-t)), 1-(m-aminobenzoyl)-4-(m-aminobenzyl)benzene (Salmabmaben(Bu-t)), and 4,4'-bis(m-aminobenzoyl)diphenylmethane (Salmadmen(Bu-t)). The ligands for these compounds were designed to feature two group 13 sites at long and varying distances from one another. The compounds were characterized by mp analyses, IF, and H-1 NMR, and X-ray structures were determined for the examples R,R'-Salcen(Bu-t){AlMe2}(2) (1), Salben(Bu-t){AlMe2}(2) (2), 1,4-Salophen(Bu-t){GaEt2}(2) (7), R,R'-Salcen(Bu-t){AlMe2}(2) (11), Salben(Bu-t){AlMeCl}(2) (13), and Salhen(Bu-t){AlMeCl}(2) (14).