Heterogenized Cu (II) salen complex grafted on graphene oxide nanosheets as a precursing catalyst for the Pd?free Sonogashira coupling

Abstract

Cu (II) salen complex immobilized on graphene oxide nanosheets [Cu (II) salen@GO] was synthesized with 3‐chloropropyltrimethoxysilan as a linker and wholly characterized using various techniques like X‐ray diffraction, Fourier‐transform infrared, scanning electron microscopy/energy‐dispersive X‐ray spectroscopy, transmission electron microscopy, as well as atomic absorption spectroscopy (AAS). Cu (II) salen@GO as an effective heterogeneous catalyst has been investigated for the Sonogashira coupling reaction in dimethylsulfoxide with good to high yield (98%) in 4 hr at 110°C when the loading of Cu was 0.7 mmol g−1 based on Cu element analysis by AAS. It was understood that heterogeneous catalyst was as active as its homogeneous analog, and presented good recoverability and no significant loss in activity within successive runs.