Immobilized zirconium-thiouracil complex on MCM-41 magnetic mesoporous as a recyclable nanocatalyst for carbon-sulfide bond formation

The synthesis and characterization of MCM-41 magnetic mesoporous material, which has been modified with zirconium-thiouracil complex (M-MCM-41@TU-ZrO), has been conducted and thoroughly analyzed using an array of techniques such as X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), elemental mapping, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), inductively coupled plasma-optical emission spectrometry (ICP-OES), thermogravimetric analysis (TGA) and vibrating sample magnetometer (VSM). The catalytic performance of M-MCM-41@TU-ZrO was tested in the synthesis of phenyl aryl sulfides through a three-component coupling reaction of aryl halides/phenolic esters with phenylboronic acid and sulfur powder in the presence of a base in PEG200 at 80-90 degrees C. Also, the synthesis of symmetrical diaryl sulfides using aryl halides and sulfur powder and M-MCM-41@TU-ZrO as a nanocatalyst in dimethyl sulfoxide at 120 degrees C was investigated. A major novelty is that this is the first time that a highly efficient magnetically recyclable zirconium nanocatalyst is used for the synthesis of unsymmetrical diaryl sulfides in the presence of arylboronic acid/S8 system as thiolating agent and phenolic esters as cross-coupling partners. The other advantages of this method are as follows: (a) the structurally diverse phenyl aryl sulfides have been synthesized in good to high yields in PEG as a green solvent; (b) starting materials, sulfur source, and catalyst are commercially available, cheap, non-toxic, and chemically stable; and (c) M-MCM-41@TU-ZrO nanocatalyst was easily removed from the reaction mixture using an external magnet and reused numerous times without any significant change in activity. Symmetric and unsymmetric diaryl sulfides were synthesized in the presence of M-MCM-41@TU-ZrO as magnetically recyclable nanocatalyst under mild conditions using aryl halides/phenolic esters, phenylboronic acid and sulfur powder.image

Automated summary

In this study, MCM-41 magnetic mesoporous material modified with zirconium-thiouracil complex was synthesized and characterized. The catalytic performance of this material in the synthesis of phenyl aryl sulfides and symmetrical diaryl sulfides was investigated. The results showed that the catalyst is highly efficient and can be easily recycled, making it a promising nanocatalyst for sulfide synthesis.