Synthesis of arylphosphonates catalyzed by Pd-imino-Py-γ-Fe2O3 as a new magnetically recyclable heterogeneous catalyst in pure water without requiring any additive

Abstract

A palladium–Schiff base complex immobilized covalently on γ-Fe₂O₃ (Pd-imino-Py-γ-Fe₂O₃) was synthesized and characterized by different methods such as XRD (X-ray diffraction), SEM (scanning electron microscopy), TEM (transmission electron microscopy), FT-IR (Fourier transform infrared spectroscopy), TGA (thermogravimetric analysis), ICP (inductively coupled plasma), XPS (X-ray photoelectron spectroscopy), VSM (vibrating sample magnetometer) and elemental analysis. It was used as a new magnetically recyclable heterogeneous Pd catalyst for the synthesis of arylphosphinates via C_sp²–P coupling reactions. A wide range of electrophilic benzenes were coupled successfully with triethylphosphite to generate the corresponding products in good to high yields in pure water without using any additive. The true heterogeneous Pd-imino-Py-γ-Fe₂O₃ could be reused simply with the aid of a magnetic bar for eight consecutive cycles without any drastic loss of its reactivity.