Synthesis of diphenyl sulfide from iodobenzene and thiophenol using Metal-Organic Framework Cu₂(NDC)₂(DABCO) as an efficient heterogeneous catalyst

A metal-organic framework Cu2(NDC)2(DABCO) was synthesized from copper nitrate trihydrate, 2,6-Napthalenedicarboxylic acid (H2NDC), and 1,4-diazabicyclo[2.2.2]octane (DABCO) by solvothermal method. Its physicochemical properties were confirmed by several techniques such as X-ray powder diffraction (PXRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Cu2(NDC)2(DABCO) appeared as well-shaped crystals. To get diphenyl sulfide as desired product from the C-S cross coupling reaction of iodobenzene and thiophenol, the Cu2(NDC)2(DABCO) was used as heterogeneous catalyst  in the presence of LiO-tBu as base. The results showed that the transformation could proceed with more than 93% reaction conversion being obtained after 6 h at 120 oC when using 5 mol% Cu2(NDC)2(DABCO) catalyst in the presence of LiO-tBu. The solid catalyst could be recovered and reused five times without a significant degradation in catalytic activity. The coupling reaction could only proceed to achieve major product in the presence of the Cu2(NDC)2(DABCO catalyst.