Metal Free Porphyrin Photocatalyst Comprising Ionic Liquid with Electron Donor Acceptor Moiety for Visible Light Assisted Oxidative Amination

摘要

Metal leaching and stability of heterogeneous catalysts is the main concern in pharmaceutical,fine chemical industries,enhancing metal contamination of the product.In this protocol,we report design and characterizations of a metal free porphyrin(MFPc)photocatalyst with electron donor acceptor(dicyano)moiety,for oxidative amination of benzyl amine under irradiation of 5 W LED light in a home-made photoreactor.Contrasted with the poor photocatalytic property of different derivatives of porphyrins,MFPc presents a significant improvement in imine formation(83 %).The influence of various factors including quantity of catalyst,duration,and intensity of light(512 W),for oxidative amination were explored.MFPc with favourable properties like Hammett acidity(1.11),band gap(1.37 eV),explored for the synthesis of pharmaceutically important benzimidazole,from o-phenylene diamine.Moreover,MFPc displayed good reusability for 6 consecutive runs with negligible decrease in yield of imine at ambient reaction conditions.Additionally,a probable mechanism for imine formation was proposed.