M-carbene catalysts (Rhodium and Iridium) based on 1,2,3-triazole ligands supported on graphene oxides

Abstract

The supported homogeneous catalysts graphene surfaces can provide special features to the catalyst systems, changing activity and selectivity such as smooth reaction conditions and recycling of the catalysts. In this work, we have prepared carbene-rhodium and iridium hybrid catalysts anchoring to a graphene oxide decorated with the 1,2,3-triazolium salt: 3-methyl-4-phenyl-1,2,3-triazolium. Thermally reduced graphene oxide (TRGO) was functionalized of triazol 4-phenyl-1,2,3-triazolium groups (TRGO-2) generated by click of the graphene material functionalized with azides (TRGO-1) with phenylacetylene catalyzed by Cu (II) salts. The triazolium salt soported on the graphene oxide TRGO-3, which contains an acid proton, have been reacted with dimers of rhodium(I) and iridium(I) and 1,5-cyclooctadiene with methoxide bridges [Rh(μ-OMe)(cod)]2 and [Ir(μ-OMe)(cod)]2 to obtain the carbene-M catalysts heterogenized of rhodium and iridium, called TRGO-Rh and TRGO-Ir. We have studied the catalytic activity of these two catalysts in a model reaction: hydrosilylation of 1-octyne with diphenyl-methylsilane. It has been found that these hybrid catalysts are quite active, but unfortunately its catalytic activity decreases in the recycled materials.