Reactions of trialkyl aluminum and trialkyl gallium with the N-tert-butyl amide of succinic acid: Molecular and supramolecular structures of the products

• N-tert-butyl amide of succinic acid reacts (LH) with tBu3M (M = Al, Ga).
• New complexes tBu2AlL (1), (tBu2ML)(tBu3M) [M = Al (2), M = Ga (3)] are formed.
• In a presence of H2O unprecedented complex [(tBu)2Ga]2L(OH) (5) is the only product.
• Crystal structure examinations show macromolecular laminar structures of 1, 3 and 5.
• Compound 2 demonstrates a dense, steadily packed network along all axes.

The reaction of the N-tert-butyl amide of succinic acid with tBu3M (M = Al, Ga) resulted in the formation of the new complexes [AltBu2{N(H)(tBu)C(O)CH2CH2COO}] (1), [MtBu2{N(H)(tBu)C(O)CH2CH2COO}(tBu3M)] [M = Al (2), M = Ga (3), and [GatBu2{N(H)(tBu)C(O)CH2CH2COO}]2 (4). The aluminum complexes 1 and 2 contained seven-membered C4O2Al rings with the Al atom bonded to the oxygen atom and coordinated to the nitrogen atom. The reaction of tBu3Ga with the N-tert-butyl amide of succinic acid resulted in the formation of a mixture of 3 and 4. The gallium complex 3 was isostructural to 2, whereas the gallium atoms in the dinuclear compound 4 were bonded to the carboxylate oxygens only forming a central Ga2C2O4 ring. X-ray studies showed that the crystalline solid obtained after crystallization from the post-reaction mixture was composed of crystals of compound 3 and co-crystals of 3 and 4. In all reactions, only the OH protons of the ligand reacted with tBuM groups with an alkane evolution, while NH protons remained unreactive. The reaction of tBu3Ga with the N-tert-butyl amide of succinic acid in a 2:1 M ratio of the reagents in the presence of water proceeded with the formation of the unprecedented compound [(GatBu2)2(OH){N(H)(tBu)C(O)CH2CH2COO}] (5) as the only product. Compound 5 was also obtained in the hydrolysis reaction of the mixture of compounds 3 and 4 isolated from the post-reaction mixture of tBu3Ga with the N-tert-butyl amide of succinic acid. The molecular and molecular packing in the crystal structures of 1–3 and 5 were determined by single-crystal X-ray diffraction. Crystal structure examinations showed laminar structures of 1, 3, and 5 and a packed crystal network of 2.

The reaction of [N(H)(tBu)C(O)CH2CH2COOH] (LH) with tBu3M (M = Al, Ga) resulted in formation of the complexes (LAltBu2) (1), (LtBu2)(tBu3M) [M = Al (2), M = Ga (3) and [LGatBu2]2 (4). An unprecedented compound [(tBu)2Ga]2L(OH) (5) was formed in the reaction of tBu3Ga with LH and H2O.Figure optionsDownload as PowerPoint slide