Silver Natural Asphalt Sulfonate (NA-SO₃Ag): Fabrication and Utilization as a New Heterogeneous, Carbonaceous, and Retrievable Nanocatalyst for C(sp²)-X (X = C, S, and Se) Bond Formation

Abstract

Silver-based catalysts are valuable catalysts in various areas of the chemical industry, organic syntheses, and transformations, and from a chemical and industrial point of view, their recycling is very important. Herein, silver natural asphalt sulfonate (NA-SO 3 Ag) was fabricated via the grafting of Ag(I) on the surface of the solid natural asphalt sulfonate as a novel and efficient recoverable sliver nanocatalyst. Natural asphalt is one of the hydrocarbons that are found in mineral veins. The structure of NA-SO 3 Ag was characterized by diverse microscopic and spectroscopic techniques including Fouriertransform infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), thermogravimetric analysis (TGA), Brunauer−Emmett−Teller (BET), X-ray diffraction (XRD), and inductively coupled plasma optical emission spectroscopy (ICP-OES) techniques. The NA-SO 3 Ag nanocatalyst was utilized for C−Se and C−S bond formation via coupling reactions of aryl halides and organic disulfides/diselenides to afford a wide variety of diaryl sulfides/selenides in good to excellent yields. Additionally, the utilization of NA-SO 3 Ag in C−C bond formation was examined in Suzuki coupling reactions successfully. For at least 6 trials, this heterogeneous catalyst can be separated and reused without any activity reduction.