Solvent-free oxidative coupling of benzylamine to imine catalyzed by FeVNi composite oxide microflowers

The solvent-free aerobic oxidative coupling of benzylamines presents a promising avenue for the green synthesis of the corresponding imines. Herein, FeVNi composite oxide microflowers were facilely prepared by a straightforward one-pot hydrothermal synthesis, and its structural and surface properties were characterized by XRD, TEM, SEM-EDS, and XPS. Under optimized conditions, the catalyst displayed a near-complete conversion of benzylamine to N -benzylidenebenzylamine, with a conversion >99 % and selectivity of 96 % (110 °C, 10 h, 1 atm O 2 ). The high efficiency and selectivity of this catalytic system likely arises from the coexistence of multiple valence states of redox-active transition metals, which is conducive to the formation of oxygen vacancies that efficiently activate molecular oxygen. This system offers significant potential for applications in synthetic organic chemistry, particularly in the sustainable synthesis of amine derivatives. • FeVNi composite oxide nanoflowers synthesized by simple one-pot hydrothermal approach. • High activity and selectivity for aerobic benzylamine coupling to imine. • High density of surface oxygen vacancies effectively activate O 2 .