Synthesis and characterization of Cu(II) containing nanosilica triazine dendrimer: A recyclable nanocomposite material for the synthesis of benzimidazoles, benzothiazoles, bis-benzimidazoles and bis-benzothiazoles

The present study describes the synthesis, characterization, and catalytic activity of Cu(II) containing nanosilica triazine dendrimer (Cu(II)-TD@nSiO(2)). The prepared catalyst was characterized by FT-IR, TGA, elemental analysis, UV-vis, FE-SEM, TEM, XPS and ICP-OES techniques. The Cu(II)-TD@nSiO(2) has been used as an efficient catalyst for the preparation of various benzimidazoles, benzothiazoles, symmetrical bis-benzimidazoles and bis-benzothiazoles under mild conditions. For the first time, we report the synthesis of an unsymmetrical bis-benzimidazole and also a compound containing both benzimidazole and benzothiazole moieties, indicating the efficiency of this catalytic system. The present method offers advantages of excellent yields, short reaction times and simple work-up. Also, the catalyst can be easily recycled and reused several times, which makes this method attractive, economic and environmentallybenign. (C) 2013 Elsevier B.V. All rights reserved.