A. Cottone, Dolores Morales, Jennifer L. Lecuivre
2002
Citations
0
Influential Citations
23
Citations
Journal
Organometallics
Abstract
Addition of 3 equiv of trimethylaluminum to tris(3,5-di-tert-butyl-2-hydroxyphenyl)-methane, 1H 3 , affords the simple, C 3 -symmetric, trimetallic species [1(AlMe 2 ) 3 ], 2. To disrupt the Al 3 O 3 bridging unit, one of the ortho-alkyl substituents from the tris(2-hydroxyphenyl)-methane platform of 1H 3 was substituted with a reactive aldehyde group to afford the ligands 3-(2,2'-methylenebis(4-methyl-6-tert-butylphenol)-5-methyl-2-hydroxybenzaldehyde,3H 3 ,and 3-(2,2'-methylenebis(4,6-di-tert-butylphenol)-5-methyl-2-hydroxybenzaldehyde,4H3, respectively. Benzylamine reacts independently with both 3H 3 and 4H 3 specifically at the aldehyde functionality, affording the mixed donor ligands 3-(2,2'-methylenebis(4-methyl-6-tert-butylphenol)-5-methylsalicylidenebenzylimine, 5H 3 , and 3-(2,2'-methylenebis(4,6-di-tert-butylphenol)-5-methylsalicylidenebenzylimine, 6H 3 , in high isolable yields. Furthermore, the Salen-type ligand, 7H 6 , can be prepared from the reaction of 1,2-ethylenediamine and 4H 3 . Two equivalents of trimethylaluminum will react with 5H 3 and 6H 3 to produce the binuclear aluminum compounds [(5)Al 2 Me 3 ], 8, and [(6)Al 2 Me 3 ], 9, respectively. If an additional equivalent of trimethylaluminum is added to 9, the trimetallic species [(6)Al 3 Me 6 ], 10, albeit as a slightly impure material, is observed, while 7H 6 reacts in an analogous manner to afford [(7)Al 6 Me 1 2 ], 11. Treatment of 8 with 1 equiv of DMSO produces the new complex [(5){AlMe 2 }-{AlMe(OSMe 2 )}], 12, wherein the substrate is coordinated to only one of a possible two aluminum centers. In contrast to this simple transformation, the separate reactions of 8 and 9 with either cyclopentanone or cyclohexanone afford the zwitterionic mononuclear complexes [(5H) + AlMe - ], 13, and [(6H) + AlMe - ], 14. Solid-state structures are reported for 2, 6H 3 , 7H 6 , and 9-13.