Synthesis of novel benzimidazole salts and microwave-assisted catalytic activity of in situ generated Pd nanoparticles from a catalyst system consisting of benzimidazol salt, Pd(OAc)2, and base in a Suzuki-Miyaura reaction

摘要

Novel benzimidazolium salts having N-benzyl or N-(4-substitutedbenzyl) groups were synthesized and their microwave-promoted catalytic activity for the Suzuki-Miyaura cross-coupling reaction were determined using in situ formed palladium(O) nanoparticles (PdNPs) from a catalytic system consisting of Pd(OAc)2/K2CC>3 in DMF/H2O. PdNPs were characterized by X-ray diffraction (XRD) pattern and particle size of in situ generated PdNPs from the Pd(lll) plane was determined to be of diameter 19.6 nm by the Debye-Scherrer equation. Moreover, the yield of the Suzuki-Miyaura reactions with aryl iodides and aryl bromides was found to be nearly quantitative. The synthesized benzimidazole salts (1-5) were identified by 1H and 13 C NMR and IR spectroscopic methods, and micro analysis. The molecular structure of 5 was also determined by X-ray crystallography.