The catalytic principle of many organic reactions is broadly divided into three steps:
- oxidative addition
- transmetallation
- reductive elimination
Because of the empty (i.e., not fully occupied by electrons) d orbital properties of transition metal elements, they can allow external electrons to enter to facilitate reduction reactions.
One of the transition metals, palladium, is the 3d orbital, and the 3d electrons themselves are easier to lose for oxidation reactions because they are farther away from the nucleus. This is why palladium-based catalysts are chosen for many organic reactions, such as coupling reactions.
There are so many kinds of Palladium catalysts on the market. The following is a summary of the names, CAS numbers and structures of commonly used palladium catalysts for your reference.
| Product Name | Structure | CAS NO. |
|---|---|---|
| Palladium(II) acetate |  | 3375-31-3 |
| Palladium(II) chloride |  | 7647-10-1 |
| Tetrakis(triphenylphosphine)palladium(0) |  | 14221-01-3 |
| Tris(dibenzylideneacetone)dipalladium(0) |  | 51364-51-3 |
| Bis(dibenzylideneacetone)palladium(0) |  | 32005-36-0 |
| PdCl2(PPh3)2 |  | 13965-03-2 |
| [1,1′-Bis(diphenylphosphino)ferrocene] dichloropalladium(II) |  | 72287-26-4 |
| Pd(dppf)Cl2 · CH2Cl2 |  | 95464-05-4 |
| Bis(benzonitrile)palladium(II) chloride |  | 14220-64-5 |
| 1,4-Bis(diphenylphosphino)butane- palladium(II) chloride |  | 29964-62-3 |
| Bis(acetonitrile)dichloropalladium(II) |  | 14592-56-4 |
| PEPPSI™-SIPr catalyst |  | 927706-57-8 |
| Dichlorobis(methyldiphenylphosphine)palladium(II) |  | 52611-08-2 |
| trans-Benzyl(chloro)bis(triphenylphosphine)palladium(II) |  | 22784-59-4 |
| [(SIPr)PdCl2]2 |  | 627878-09-5 |
| P(t-Bu)3 Pd G2 |  | 1375325-71-5 |
| [(R)-(+)-2,2′-Bis(diphenylphosphino)-1,1′- binaphthyl]palladium(II) chloride |  | 115826-95-4 |
| Palladium(π-cinnamyl) chloride dimer |  | 12131-44-1 |
| PEPPSI™-IPr catalyst |  | 905459-27-0 |
| PdCl2(dtbpf) |  | 95408-45-0 |
| PdCl2[P(o-Tol)3]2 |  | 40691-33-6 |
| Dichlorobis(tricyclohexylphosphine)palladium(II) |  | 29934-17-6 |
| PdCl2(dppe) |  | 19978-61-1 |
| PdCl2(dippp) |  | 59831-02-6 |
| Pd(amphos)Cl2 |  | 887919-35-9 |
| Pd(t-Bu3P)2 |  | 53199-31-8 |
| Dichlorobis(di-tert-butylphenylphosphine)palladium(II) |  | 34409-44-4 |
| RuPhos Pd G1 |  | 1028206-60-1 |
| RuPhos Pd G2 |  | 1375325-68-0 |
| RuPhos Pd G3 |  | 1445085-77-7 |
| Xphos Pd G1 |  | 1028206-56-5 |
| Xphos Pd G2 |  | 1310584-14-5 |
| Xphos Pd G3 |  | 1445085-55-1 |
| BrettPhos Pd G1 |  | / |
| BrettPhos Pd G3 |  | 1470372-59-8 |
| XantPhos Pd G3 |  | / |
| DavePhos Pd G3 |  | 1445085-87-9 |
| Aphos Pd G3 |  | / |
| cataCXium® A Pd G3 |  | / |
| DPPF Pd G3 |  | / |