Ligand-free direct C-arylation of heterocycles with aryl halides over a metal-organic framework Cu2(BPDC)2(BPY) as an efficient and robust heterogeneous catalyst

Abstract

A crystalline porous metal-organic framework Cu2(BPDC)2(BPY) was synthesized and characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR), atomic absorption spectrophotometry (AAS), hydrogen temperature-programmed reduction (H2-TPR), and nitrogen physisorption measurements. The Cu2(BPDC)2(BPY) exhibited high catalytic activity in direct CH arylation reactions between heterocyles and aryl halides. The Cu2(BPDC)2(BPY)-catalyzed CH arylation reaction could proceed to higher conversion than that of the reaction using Cu3(BTC)2, Cu(BDC), Cu(BPDC), and Cu2(BDC)2(BPY) as catalyst. Furthermore, under our conditions, the Cu2(BPDC)2(BPY) also exhibited significantly higher activity than that of common copper salts, including Cu(NO3)2, CuCl, CuCl2, and CuI. Excellent reusability of the Cu-MOF in the direct heterocycle CH arylation reaction was achieved.