Allylpalladium chloride dimer

Allylpalladium(II) chloride dimer is a chemical compound with the formula (η3- C3H5)2Pd2Cl2. This yellow air-stable compound is an important catalyst used in organic synthesis.

Synthesis and reactions
The compound is prepared by purging carbon monoxide through a methanolic aqueous solution of palladium(II) chloride, sodium chloride, and allyl chloride.
 * 2Na2PdCl4 +  2 CH2=CHCH2Cl  +  2 CO  +  2 H2O   →   (C3H5)2Pd2Cl2  +  4 NaCl  +  2 CO2  +  4 HCl

APC reacts with sources of cyclopentadienyl anion to give the corresponding 18e complex:
 * (C3H5)2Pd2Cl2 +  2 NaC5H5   →   2  Pd(η3-C3H5)(η5-C5H5)  +  2 NaCl