PdCl2

Palladium(II) chloride, with the chemical formula PdCl2, is an inorganic palladium salt that serves as a common source of Pd(II) in coordination chemistry and organometallic synthesis. In its anhydrous form it is a dark brown to black solid, and it is relatively insoluble in water.

PdCl2 can be prepared by direct chlorination of palladium metal or by dissolution of palladium in aqua regia followed by precipitation of the chloride. The solid readily forms various coordination and adduct species, and in aqueous solutions its chemistry is dominated by the formation of chloro-complexes such as [PdCl4]2− in the presence of excess chloride. In non-aqueous media and with suitable ligands, PdCl2 can undergo ligand substitution to give a wide range of palladium(II) coordination compounds.

As a reagent, PdCl2 is widely used as a convenient precursor to many palladium(II) complexes employed in catalysis and organic synthesis. It is a common starting material for generating ligated Pd(II) species, which can be reduced to Pd(0) catalysts or converted into a variety of Pd(II) catalysts for cross-coupling reactions such as Suzuki–Miyaura, Heck, and Sonogashira couplings. Its versatility as a Pd(II) source stems from its ability to form stable adducts with phosphines, nitrogen donors, and other ligands, enabling the construction of numerous catalytic systems.

Safety considerations for PdCl2 and its compounds include potential irritant effects; handling should follow standard laboratory practices for toxic metal salts, including the use of gloves, eye protection, and adequate ventilation. palladium compounds can be hazardous if ingested, inhaled, or absorbed through the skin.