A PdII Complex Bearing a Benzimidazole-Derived Ligand with Potentially “Mesoionic and Remote” Character and Its Catalytic Activity



The oxidative addition of palladium(0) to the C2-protected 5-bromo-2-methylbenzimidazolium tetrafluoroborate 3 affords the complex trans-[PdBr(bimy)(PPh3)2]BF4 (4), which is the first complex of an unprecedented benzimidazole-derived ligand (bimy) with a potentially “mesoionic and remote” character. DFT calculations revealed that the bimy ligand bridges the gap between the mesoionic pyrazolin-4-ylidene and the anionic phenyl ligand. A preliminary catalytic study revealed the promising activity of 4 in the Sonogashira coupling of aryl bromides with phenylacetylene.