Synthesis of 2-substituted benzimidazoles and 2-aryl-1H-benzimidazoles using [Zn(bpdo)2·2H2O]2+/MCM-41 catalyst under solvent-free conditions

A cationic zinc(II) complex of the 2,2′-bipyridine-1,1′-dioxide ligand was prepared and loaded onto mesoporous silica nanochannels. The catalyst was characterized by powder X-ray diffraction, transmission electron microscopy, BET nitrogen adsorption–desorption method and FT-IR spectroscopy. The resulting material was used as a new catalyst in a novel and efficient procedure for the synthesis of 2-substituted benzimidazoles and 2-aryl-1 H -benzimidazoles by simple condensation of O -phenylenediamine and carboxylic acids under solvent-free conditions.