One-pot formic acid dehydrogenation and synthesis of benzene-fused heterocycles over reusable AgPd/WO2.72 nanocatalyst

Abstract

Using nanoparticles (NPs) to catalyze multiple chemical reactions in one-pot and to achieve high-yield syntheses of functional molecules/materials is an important direction in NP chemistry, catalysis and applications. In this article, we report a nanocomposite of AgPd NPs anchored on WO_2.72 nanorods (NRs) (denoted as AgPd/WO_2.72) as a general catalyst for formic acid dehydrogenation and transfer hydrogenation from Ar-NO₂ to Ar-NH₂ that further reacts with aldehydes to form benzene-fused heterocyclic compounds. The AgPd/WO_2.72 catalysis is Ag/Pd dependent and Ag₄₈Pd₅₂ is the most active composition for the multiple chemical reactions. The high activity of AgPd/WO_2.72 arises from strong interfacial interaction between AgPd and WO_2.72, resulting in AgPd lattice expansion and electron polarization from AgPd to WO_2.72. The syntheses proceed in one-pot reactions among formic acid, 2-nitrophenol (or 2-nitroaniline, or 2-nitrothiophenol) and aldehydes in dioxane/water (2/1 v/v) at 80–90 °C, leading to one-pot syntheses of benzoxazoles, benzimidazoles and benzothiazoles that are key ring structures present in functional compounds for pharmaceutical, optical and polymer applications.