Recyclable and dual active catalyst of copper nanocluster-bound graphitic carbon nitride for the photo-induced synthesis of arylsulfones

Abstract

A photocatalytic system of Cu(0) nanocluster-bound graphitic carbon nitride (Cu(0)-g-C3N4) was developed for three-component arylsulfonylation reactions. The Cu(0)-g-C3N4 nanocomposite has a structure in which 2–5 nm metallic Cu nanoclusters are anchored on the surface of g-C3N4 nanosheets. The Cu(0) clusters were synthesized by reducing Cu2+ ions with ascorbic acid in the presence of g-C3N4 nanosheets. Cu(0)-g-C3N4 was designed to exhibit dual catalytic activity involving the transfer of photo-induced electrons from g-C3N4 to Cu(0) for the reduction of arylhalides, while the holes in g-C3N4 oxidize the sulfur dioxide anion. The structure of the catalyst was confirmed by electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The well-defined, air-stable Cu(0)-g-C3N4 catalyst effectively promotes the sulfonylation of aryl iodides, thiourea dioxide, and electrophiles to afford the corresponding arylsulfonyl compounds in moderate to good yields. The reusability of the catalyst was also evaluated, and it could be reused up to ten times in arylsulfonylation without the loss of its activity.