Synthesis, spectroscopic, structural characterizations, and catalytic properties of cyanide-bridged heteronuclear metal organic frameworks with imidazole

Three new cyanide-bridged metal complexes of the general formula [Cu2(μ-im)2(im)4M(μ-CN)4]n (where M ​= ​Ni(II) for 1, Pd(II) for 2, and Pt(II) for 3; im: imidazole) have been synthesized. All 1–3 were investigated using different and properly chosen physicochemical methods: Fourier transform infrared (FT-IR) and Raman spectroscopies (R), thermal analysis (TG, DTG, DTA), powder and single-crystal X-ray diffraction (PXRD and SC-XRD). The polymeric structures of all complexes crystalize in the same triclinic P-1 space group. Brunauer-Emmett-Teller (BET) method was used for the surface area analysis. The average particle size and morphology were estimated by scanning and transmission electron microscope (SEM and TEM). The heterogeneous catalytic activity of complex 2 catalysts was evaluated on the Suzuki-Miyaura reaction between selected aryl halides and phenyboronic acid. Complex 2 exhibits moderate to high heterogeneous catalyst activity for the Suzuki C–C coupling reaction in an organic/water solvent environment. It was found that the heterometallic complexes obtained in this study have 3-dimensional coordination polymers. From the structural analysis, each Cu(II) ion is coordinated by two nitrogen atoms from the cyanide ligands and four nitrogen atoms from the imidazole ligands, thus showing a distorted octahedral coordination geometry. With this, each M ion [M ​= ​Ni(II) in 1, Pd(II) in 2 and Pt(II) in 3] was coordinated by four carbon atoms from cyanide ligands, thus showing a square planar coordination geometry. Moreover, heterogeneous catalytic activity of 2 catalyst was evaluated on Suzuki-Miyaura reaction between selected aryl halides and phenyboronic acid. The complex 2 exhibits moderate to high heterogeneous catalyst activity for the Suzuki C–C coupling reaction in an organic/water solvent environment. [Display omitted] •The crystal structures of the MOFs 1–3 were determined by the single crystal X-ray diffraction technique.•The structural analyses shows that heterometallic complexes 1–3 have 3D coordination polymers.•The efficiency of bimetallic MOF catalyst containing palladium and copper metals (2) synthesized in this study on Suzuki C–C coupling reaction was investigated under various conditions.