Bimetallic Aluminum and Gallium Chelates with N₂O₂ Ligands

Abstract

A wide range of bimetallic aluminum molecules are formed in combinations between Salen Schiff base ligands and either AlR 3 or AlR 2 Cl. They are of the general formulas L(AlR 2 ) 2 and L(AlRCl) 2 with R ) alkyl and L ) Salen( t Bu) ligand with relatively unusual "backbone" connections between the nitrogen atoms, 1,2-cyclohexylene (Salcen( t Bu)), 1,4-butylene (Salben( t Bu)), 1,5-pentylene (Salpten( t Bu)), 1,6-hexylene (Salhen( t Bu)), and 1,4-phenylene (1,4-Salophen( t Bu)). Additionally, previously unknown ligands were employed with the "backbones" 1,4-bis(p-aminobenzyl)benzene (Salmaben( t Bu)), 1-(m-aminobenzoyl)-4-(m-aminobenzyl)benzene (Salmabmaben( t Bu)), and 4,4′-bis(m-aminobenzoyl)diphenylmethane (Salmadmen( t Bu)). 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, IR, and 1 H NMR, and X-ray structures were determined for the examples R,R′-Salcen( t Bu){AlMe 2 } 2 (1), Salben( t Bu){AlMe 2 } 2 (2), 1,4-Salophen( t Bu){GaEt 2 } 2 (7), R,R′-Salcen( t Bu){AlMeCl} 2 (11), Salben( t Bu){AlMeCl} 2 (13), and Salhen( t Bu){AlMeCl} 2 (14).

Boron halide chelate compounds and their activity towards the demethylation of trimethylphosphate

“…In an NMR tube, trimethylphosphate was added to an equimolar solution of the compound (1)(2)(3)(4)(5) in CDCl 3 and held at room temperature for 30 min and 24 h. The reaction was monitored by 1 H NMR ( Table 2).…”

“…The versatility of the ligand allows for the isolation of both monometallic and bimetallic derivatives usually involving the group 13 elements. For example, many compounds have been reported for aluminum (3)(4)(5), gallium (5,6), and indium (7,8). However, boron compounds of this type have been studied less extensively (9)(10)(11).…”

“…Although these compounds are interesting from a fundamental standpoint, they are limited in usefulness because of their lack of reactivity or Lewis acid potential. In this paper we report the high-yield syntheses of new Salen-supported boron chloride derivatives, L[BCl 2 ] 2 (1)(2)(3)(4)(5). Preliminary work indicates that these chloride compounds will undergo salt elimination reac-tions, allowing for further derivatization of the boron atoms and thereby increasing their potential utility (13).…”

Binuclear Magnesium, Calcium and Zinc Complexes Based on Bis(salicylaldimine) Ligands with Rigid Bridges

“…These ligands are abbreviated according to the nature of the bridge. The ligand with the rigid p ‐phenylene bridge (PARA‐H 2 , which has been used in the syntheses of dinuclear Al and Ga complexes)7 and the permethylated p ‐phenylene bridge (Me 4 PARA‐H 2 ) fix the metal ··· metal distance in the range of circa 5.5–8.5 Å 8. The ligand with the m ‐phenylene bridge (META‐H 2 , for which a dinuclear Zn complex is known)9 is designed for bimetallic complexes in which the metal ··· metal distances can vary over a much larger range (circa 2.5–8 Å) 8.…”

Ketiminate‐Supported LiCl Cages and Group 13 Complexes

“…[23] The N( [23] 1 H NMR confirmed the assignment of a methyl carbon in the solid-state structures, with peaks corresponding to the Al-methyl at -0.68 ppm in each spectrum, which is in the normal range for N,O-chelated Al-CH 3 protons (-0.7 to -1.11 ppm). [24,25] Aluminum complexes of aryl-substituted ketiminate ligands have been reported, [6,7,25,26] so synthesis of a novel aluminum-ArL 1 complex was not pursued. However, the structure of 2 can be compared to previously reported Dipp-substituted ketiminate aluminum complexes.…”