Cyclometallated Pd(II) thiosemicarbazone complexes: new catalyst precursors for Suzuki-coupling reactions

Four tridentate [C,N,S] thiosemicarbazone Pd(II) complexes were applied as catalyst precursors for the Suzuki–Miyaura coupling of a variety of aryl halides and aryl boronic acids. After screening various catalytic conditions, it was found that one dinuclear complex IV containing the bis(diphenylphosphino) ferrocene spacer was able to efficiently catalyze these reactions with yields up to 99% irrespective of the type of aryl substituent on the substrate.