Copper supported β-cyclodextrin functionalized PEGylated mesoporous silica nanoparticle -graphene oxide hybrid: An efficient and recyclable nano-catalyst for straightforward synthesis of 2-arylbenzimidazoles and 1,2,3-triazoles

Abstract

β-Cyclodextrin functionalized PEGylated mesoporous silica nanoparticles-graphene oxide hybrid has been introduced as a heterogeneous support for immobilization of copper catalyst (denoted as Cu@βCD-PEG-mesoGO). Mesoporous silica nanoparticles-graphene oxide hybrid (mesoGO) was synthesized and functionalized by PEG600 ended β-cyclodextrin. Then, Cu was immobilized onto the later modified nanoparticles. Cu@βCD-PEG-mesoGO was evaluated for the synthesis of benzimidazoles and 1,2,3-triazoles. The synthesis of 2-aryl benzimidazole derivatives from o-phenylenediamines and benzaldehydes via aerobic C-N bond oxidation reaction was successfully performed using Cu@βCD-PEG-mesoGO as a “green” catalyst. The catalyst was also applied for the synthesis of 1,2,3-triazole derivatives via three component click reaction of alkynes, benzylbromides and sodium azide. The catalyst recovery test was performed, and showed that this catalyst is highly reusable without a significant decrease in its activity. This catalyst has outstanding properties such as high efficiency and turnover frequency (TOF), simple product work-up, utilization of H2O as a green solvent, mild reaction conditions, and easy catalyst recovery.