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.

An environmentally benign protocol for the synthesis of biologically important 1,5-benzodiazepines is described, where polyfluorinated–zinc(II)phthalocyanine complex covalently anchored onto the surface of functionalized silica gel is acting as an efficient heterogeneous catalyst. High turnover frequency, mild reaction conditions, high selectivity, and easy recovery and reusability of the catalyst render the present protocol highly indispensable to address the industrial prerequisites and environmental concerns.Figure optionsDownload as PowerPoint slideHighlights
► Silica supported polyfluorinated–zinc(II) phthalocyanine complex.
► Efficient, recoverable and re-usable catalyst with consistent activity.
► Characterizations and application of inorganic–organic hybrid catalyst.
► Solvent-free synthesis of biologically important 1,5-benzodiazepines.