Organoaluminum derived from Schiff bases: Synthesis, characterization and catalytic performance in hydroboration

Abstract

In the process of the development of green chemistry, non-noble metal catalysts have become one of the research hotspots. The abundant aluminum has entered the research scope of chemists. Four organoaluminum derived from halogen-substituted Schiff bases were prepared: (2-(((2,6-difluorophenyl)imino)methyl)phenoxy)dimethylaluminum (C1), (2-(((3-chloro-4-fluorophenyl)imino)methyl)phenoxy)dimethylaluminum (C2), (2-(((2-chlorophenyl)imino)methyl)phenoxy)diethylaluminum (C3), (2-(((4-chlorophenyl)imino)methyl)phenoxy)diethylaluminum (C4). All organoaluminum compounds were characterized using 1H NMR, 13C NMR, 19F NMR spectroscopy, and X-ray single crystal diffraction. XRD proved that the aluminum centers of these organoaluminum compounds are all twisted six-membered ring structures. They were used for the hydroboration of aldehydes and ketones, showing excellent results. This provided an additional catalyst for the reduction of carbonyl compounds.