g-C3N4/γ-Fe2O3/TiO2/Pd: a new magnetically separable photocatalyst for visible-light-driven fluoride-free Hiyama and Suzuki–Miyaura cross-coupling reactions at room temperature

Abstract

In this paper, a new visible-light harvesting photocatalyst denoted as g-C₃N₄/γ-Fe₂O₃/TiO₂/Pd was successfully fabricated and fully characterized by different techniques including FT-IR, XPS, XRD, TEM, SEM, elemental mapping, VSM, DRS, and ICP analysis. The as-prepared catalyst was utilized as an efficient magnetically separable photocatalyst in the fluoride-free Hiyama and Suzuki–Miyaura cross-coupling reactions at room temperature under visible light irradiation. By using this approach good to excellent yields of biaryls were achieved from the reaction of various aryl iodides/bromides and even chlorides as highly challenging substrates, which are more available and cheaper than aryl iodides and bromides, with triethoxyphenylsilane or phenylboronic acid. The superior photocatalytic activity of g-C₃N₄/γ-Fe₂O₃/TiO₂/Pd could be attributed to the synergistic catalytic effects of Pd nanoparticles and g-C₃N₄/γ-Fe₂O₃/TiO₂. Utilizing a sustainable and safe light source, no need to use any additive or heat, using an eco-friendly solvent and long-term stability and magnetic recyclability of the catalyst for at least seven successive runs are the advantages that support the current protocol towards green chemistry.