Metal borides (MBs) emerge as a versatile class of nanomaterials, featuring high stability and bifunctional Lewis-acidic/basic active sites. Despite these properties, their applications in C─N bond formation are less explored. Herein, we report the first systematic use of M2B-type boride nanoparticles as efficient and magnetically recoverable catalysts for the condensation of aldehydes with p-toluenesulfonamide under mild conditions. The synthesized CoZnB-NPs exhibit partially oxidized and hydroxylated surfaces with Lewis-acidic (B/Zn) and Lewis-basic (Co) sites, where the synergistic interaction between Co and Zn centers facilitates charge transfer and stabilizes reactive intermediates. A series of mono- and bimetallic boride NPs are synthesized via aqueous NaBH4 reduction and comprehensively characterized by Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM). CoZnB-NPs achieve yields of up to 93% within 1 h using an optimal catalyst loading of 3 mg in toluene, and demonstrate excellent magnetic recoverability and stability. This study highlights MB-NPs as a surface-engineered, high-performance platform for selective C─N bond formation, providing insights into the design of bimetallic boride nanocatalysts for sustainable catalysis.
