MoCxNy Heterostructure Derived from Polyoxometalate Hybrid for Hydrogen Transfer Cascade Coupling of Nitroarenes and Alcohols

Abstract

The catalytic hydrogen transfer cascade reaction that couples nitro compounds with alcohols to produce amines is highly valued for its exceptional atom economy and efficiency. Nevertheless, the complex multistep nature of this reaction often results in suboptimal performance when using single-site catalysts. In this study, we synthesized a bifunctional catalyst, MoCxNy heterostructure on silicon-carbon-nitrogen composite support (MoCxNy@SiCN), which possesses both dehydrogenation and hydrogenation capabilities. This was achieved through a self-assembly-carbonization/nitridation technique by using polyoxometalate, histidine, and silicic acid as precursors. Characterization and mechanistic experiments indicated that MoCxNy heterostructure could boost the catalyst's hydrogenation activity towards key intermediate species.Moreover, the enhanced hybridization between Mo2C and Mo2N promotes the spill-over hydrogen effect during the reductive coupling process. Consequently, the MoCxNy@SiCN catalyst achieves yields exceeding 90% for a variety of aromatic amines, and even for aliphatic amines. This research presents a strategy for designing non-precious metal catalysts and offers an economical method for amine synthesis.