Systematic and efficient synthesis of β-diketiminato aluminum halides and their structural characterization

• Published in: Tetrahedron letters 2021-03, Vol.68, p.152942, Article 152942
• Main Authors: Wang, Xinmiao, Meng, Yinfeng, Hou, Lei, Wang, Yaoyu, Wang, Wenyuan
• Format: Article
• Language: English
• Subjects: Aluminum complex; Halogen substitution; Intermediate; Reactivity; β-Diketiminate ligand
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/j.tetlet.2021.152942

[Display omitted] •There is an efficient salt substitution reaction between β – diimidaluminium halides.•An intermediate state of β-diketiminato trimethyl aluminum in the process of producing aluminum dimethylates from β-diketiminate.•Efficient synthesis of series of β-diketiminato aluminum complexes. Kinds of β-diketiminato aluminum complexes, L1AlMe2 (1), L1AlMeI (2), L1AlI2 (3), L1AlBr2 (4), L2AlBr2 (5), L1AlCl2 (6), L2AlCl2 (7) (L1[1] = [C(Ph)C(CH2)4C(NDip)2]-, L2[2] = [PhC(PhCN-Dip)2]-, where Dip = 2,6-iPr2C6H3) were obtained from the reaction of trimethylaluminum, iodine, aluminum tribromide, KCl with the corresponding β-diketiminate or β-diketiminato aluminum complex, respectively. All compounds were characterized by 1H NMR and 13C NMR spectroscopy, single-crystal X-ray structural analysis, and elemental analysis. Compound 3 was found to be obtained from compound 1 or 2 with two or one equivalent of iodine, respectively. We found an intermediate, L1AlMe3 (8) in the process of that ligand formed compound 1 and separated its single crystal structure. In the process of reduction of β – diimidaluminium diiodide with potassium powder, we were surprised to find that the halogen replacement reaction can occur when β - diimidaluminium diiodide and KCl efficiently generate β – diimidaluminium dichloride.