A Highly Active Catalyst System for Suzuki–Miyaura Coupling of Aryl Chlorides

A series of new Pd­(II)
complexes with simple structures were designed
and synthesized for Suzuki–Miyaura coupling reactions of aryl
chlorides. The new Pd­(II) complexes contain bidentate amine ligands,
and their structures were characterized by single-crystal X-ray diffraction.
They are highly efficient for Suzuki–Miyaura coupling reactions
of aryl chlorides with low catalyst loadings (0.01 mol %) in aqueous
media at room temperature. Two possible reaction pathways involving
a PdII/0/II and a PdII/IV/II catalytic cycle
are proposed, and the mechanism was further investigated using density
functional theory (DFT) calculations.