Herrmann's catalyst

Herrmann's catalyst is an organopalladium compound that is a popular catalyst for the Heck reaction. It is a yellow air-stable solid that is soluble in organic solvents. Under conditions for catalysis, the acetate group is lost and the Pd-C bond undergoes protonolysis, giving rise to a source of "PdP(o-tol)₃".

Herrmann's catalyst

Identifiers
CAS Number	172418-32-5
ChemSpider	10136140
PubChem CID	15978061
UNII	0K4FY6KS4N
CompTox Dashboard (EPA)	DTXSID40704833
Properties
Chemical formula	C46H46O4P2Pd2
Molar mass	937.66 g·mol−1
Appearance	Yellow solid
Melting point	123–125 °C (253–257 °F; 396–398 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

The complex is made by reaction of tris(o-tolyl)phosphine with palladium(II) acetate:^[1]

2 Pd(OAc)₂ + 2 P(o−tolyl)₃ → 2 HOAc + Pd₂(OAc)₂[P(o−tolyl)(o−tolyl)₂]₂

Many analogues of Hermann's catalyst have been developed, e.g. palladacycles obtained from 2-aminobiphenyl.^[2]