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

Abstract

Novel benzimidazolium salts having N-benzyl or N-(4-substitutedbenzyl) groups were synthesized and their microwave-promoted catalytic activity for the SuzukiMiyaura cross-coupling reaction were determined using in situ formed palladium(0) nanoparticles (PdNPs) from a catalytic system consisting of Pd(OAc) 2 /K2CO 3 in DMF/H 2 O. PdNPs were characterized by X-ray diffraction (XRD) pattern and particle size of in situ generated PdNPs from the Pd(111) plane was determined to be of diameter 19.6 nm by the DebyeScherrer equation. Moreover, the yield of the SuzukiMiyaura reactions with aryl iodides and aryl bromides was found to be nearly quantitative. The synthesized benzimidazole salts (15) were identified by 1 H and 13 C NMR and IR spectroscopic methods, and micro analysis. The molecular structure of 5 was also determined by X-ray crystallography.