Palladium compounds

Palladium forms a variety of ionic, coordination, and organopalladium compounds, typically with oxidation state Pd0 or Pd2+.

Another precursor to coordination compounds of palladium is sodium tetrachloropalladate, to which dibenzylideneacetone (dba) and acetylacetonate may be coordinated to form tris(dibenzylideneacetone)dipalladium(0) (Pd2(dba)3)[3] and palladium(II) bis(acetylacetonate), respectively.

[4] Both ionic and coordination palladium compounds are frequently used to catalyze cross-coupling reactions.

After transmetalation with an organometallic compound, two organic ligands to Pd2+ may exit the palladium complex and combine, forming a coupling product and regenerating Pd0 (reductive elimination).

Bulky, electron-rich ligands such as tris(2,4,6-trimethoxyphenyl)phosphine result in catalysts that are more reactive in the oxidative addition step[2] and can catalyze the coupling of aryl chlorides, which are typically unreactive.