A novel N-heterocyclic carbene-palladium modified metal–organic framework (Sm-MOF-Pd) for Suzuki-Miyaura cross-coupling reaction

Abstract

A novel 3D Sm-MOF, namely {n[Sm(L)2·2(H2O)]·(Cl)n, H2L+Cl- = 1,3-bis(4-carboxybenzyl)-imidazolium chloride)}, was prepared under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction. Then the N-heterocyclic carbene-Pd(II) functionalized metal–organic framework (Sm-MOF-Pd) was yielded by introducing Pd active sites into the Sm-MOF by the post-synthesis modification (PSM) method. This new material was characterized by powder X-ray diffraction (PXRD), thermogravimetric analyses (TGA), scanning electron microscopy (SEM), transmission electron (TEM), energy-dispersive X-ray spectroscopy (EDS), inductively coupled plasma optical emission spectroscopy (ICP-OES) and X-ray photoelectron spectroscopy (XPS) measurements, showing that Pd(II) ions were uniformly dispersed in the Sm-MOF after PSM. The Sm-MOF-Pd reached a catalytic yield of 99 % in Suzuki-Miyaura cross-coupling reactions under optimal reaction conditions. After four cycles, it still maintained high catalytic activity.