Increased catalytic activity through ZnMo₇O₂₄/g-C₃N₄ heterostructured assemblies for greener indole condensation...

As an economical conjugated polymer, graphitic carbon nitride (g-C₃N₄) has recently attracted much attention due to its exciting chemical and thermal stability and easy availability. Herein, we constructed a metal-coordinated graphitic carbon nitride (M-g-C₃N₄) catalyst through simple impregnation and calcination methods and used it as a new heterogeneous catalyst for the efficient synthesis of bis (indolyl) methanes and trisindolines under mild conditions. This reaction is performed efficiently in water as an environmentally friendly solvent at ambient conditions. The ZnMo₇O₂₄/g-C₃N₄ nanocomposite was synthesized by a simple method by immobilizing Mo₇O₂₄(NH₄)₆·4H₂O and ZnCl₂ on the surface of g-C₃N₄ under hydrothermal conditions. It was characterized by FT-IR, EDS, and electronic scanning microscopy (SEM). The metal doping of Mo and Zn on the surface of graphitic carbon nitride leads to the formation of a green catalyst that gives good to excellent yields of products in short reaction times with an easy working procedure. In addition, the ZnMo₇O₂₄/g-C₃N₄ catalyst could be reused at least five runs without apparent loss of efficiency.