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

A crystalline porous metal-organic framework Cu-2(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 (H-2-TPR), and nitrogen physisorption measurements. The Cu-2(BPDC)(2)(BPY) exhibited high catalytic activity in direct C-H arylation reactions between heterocyles and aryl halides. The Cu-2(BPDC)(2)(BPY)-catalyzed C-H arylation reaction could proceed to higher conversion than that of the reaction using Cu-3(BTC)(2)Cu(BDC),Cu(BPDC), and Cu-2(BDC)(2)(BPY) as catalyst. Furthermore, under our conditions, the Cu-2(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 C-H arylation reaction was achieved. (C) 2014 Published by Elsevier B.V.