ABSTRACT
New heterometallic aluminium-alkali metal compounds have been prepared using Schiff bases with electron withdrawing substituents as ligands. The synthesis of these new species was achieved via the reaction of AlMe3 with the freshly prepared alkali-metallated ligand. The derivatives formed were characterized by NMR in solution and by single crystal X-ray diffraction in the solid state. Aluminate derivatives with lithium and sodium were prepared and a clear influence of the alkali metal in the final outcome is observed. The presence of a Na···F interaction in the solid state has a stabilization effect and the species [NaAlMe3L]2 can de isolated for the first time, which was not possible when using Schiff bases without electron withdrawing substituents as ligands.
Subject(s)
Aluminum Compounds/chemistry , Hydrocarbons, Fluorinated/chemistry , Models, Molecular , Schiff Bases/chemistry , Molecular StructureABSTRACT
New heterobimetallic aluminates with well-defined structures bearing bidentate Schiff bases as ligands have been prepared. The ligands studied are PhO-CH[double bond, length as m-dash]N-Ar (Ar = C6H5 (La) and 2,6-iPr-C6H3 (Lb)), with and without donor substituents in the ortho position of the arene ring bonded to the iminic nitrogen. To prepare the heterometallic species, the HL proligands were treated with the appropriate alkali metal precursor and then AlMe3 was added. In these reactions the alkali metal size has a substantial influence on the outcome. For lithium, the formation of [LiAlMe3(L)]21(a-b) compounds was straightforward and their nuclearity in the solid state was confirmed by X-ray studies. When moving to sodium, the analogous species [NaAlMe3(L)]n initially formed, quickly evolved to [NaAlMe2(L)2]n3(a-b) in solution. As well, for potassium, the initial derivatives formed [KAlMe3L] progressed very rapidly to the generation of [KAlMe2L2] as evidenced from the isolation of [KAlMe2(Lb)2] 4b as a crystalline product. Furthermore, for potassium the unique species [KAlMe(Lb)3] 5b was isolated which shows, as a striking feature, the presence of an unusual tripodal metalloligand.
