Polyfluorinated–zinc(II)phthalocyanine complex immobilized on silica: A novel, highly selective and recyclable inorganic–organic hybrid catalyst for the synthesis of biologically important 1,5-benzodiazepines

A novel, efficient and recyclable catalyst was prepared by covalent grafting of polyfluorinated–zinc(II)phthalocyanine complex onto functionalized silica gel. The activity of the catalyst was investigated for the solvent-free synthesis of 1,5-benzodiazepines at room temperature. The immobilized catalyst was characterized by elemental analysis (CHN), diffuse reflectance UV–Vis spectroscopy, solid-state 13C CPMAS and 29Si CPMAS NMR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), BET surface area analysis, energy dispersive X-ray fluorescence (ED-XRF), Fourier transform Infrared (FT-IR) and atomic absorption spectroscopy (AAS) techniques. Short reaction time, mild reaction conditions, high turnover numbers, and easy recovery and reusability of the catalyst make this method a novel, economic and waste-free chemical process for the synthesis of biologically important 1,5-benzodiazepines.