Visible-Light-Driven Photocatalytic Coupling of Neat Benzylamine over a Bi-Ellagate Metal–Organic Framework

Selective aerobic oxidation of benzylamine to N,N-benzylidenebenzylamine was achieved using a bismuth ellagate (Bi-ellagate) metal–organic framework (MOF) under simulated visible light irradiation. The bismuth ellagate photocatalyst was characterized using several spectroscopic techniques: powder X-ray diffraction (PXRD), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and nitrogen sorption measurements. Product formation was confirmed using 1H-NMR, 13C-NMR, and FTIR. The photocatalytic performance of Bi-ellagate was studied for the first time, which exhibits a band gap value of 2.62 eV, endowing it with a high photocatalytic activity under visible light irradiation. The reaction product, N,N-benzylidenebenzylamine, was selectively obtained with a high conversion yield of ∼96% under solvent-free conditions compared to other control experiments. The Bi-ellagate photocatalyst was recovered and reused four times without any significant loss in its activity, which provides an eco-friendly, low-cost, recyclable, and efficient photocatalyst for potential photocatalytic applications.