Aqueous suspension of biocompatible reduced graphene oxide- Au NPs composite as an effective recyclable catalyst in a Betti reaction.

Synthesis of noble metal nanoparticles (NPs) on modified graphene oxide with biocompatible polymers has attracted significant due to their unique properties and various applications. In this research, covalent-modified graphene oxide (MGO) with diacid terminated poly (ethylene glycol) (PEG) was used as a substrate and stabilizing of Au (ш). The reduction of MGO-Au (ш) complex with hydrazine monohydrate under reflux condition obtained biocompatible reduced MGO (rMGO)-Au NPs. Diacid terminated PEG obtained from the reaction of PEG with succinic anhydride in the presence of N,N- dicyclohexylcarbodiimide (DCC) and 4-methylamino pyridine (DMAP) was attached to GO sheets to prevent from the aggregation of rMGO sheets and Au NPs. The resulting aqueous suspension was characterized through UV-vis, FT-IR, Raman, XRD, DLS-zeta potential, SEM, EDX and TEM. Furthermore, nanocomposite showed good catalytic behavior in Betti reaction- synthesis of 1-(α-aminoalkyl)-2-naphthols. The favorable properties of colloidal nanocomposite were attributed to the stable and well distribution Au NPs on rMGO.