text: The use of organometallic structures led by π–metal bonding plays an enormous role in the catalysis of organic reactions. The Stille reaction is a widely known and important reaction in organic synthesis. π interactions with the Pd catalyst in this reaction are almost necessary in pushing this reaction to completion (alkyl groups transfer is rather slow).
  Other widely known reactions based on π–metal catalysis interactions are:
  *Heck reaction 
  *Hiyama coupling 
  *Kumada coupling
  *Negishi coupling 
  *Petasis reaction 
  *Sonogashira coupling
  *Suzuki reaction.
  π–metal interactions can also be involved directly with the function of ligands on the catalyst. Chemistry involving nickel catalysis of Suzuki reactions was greatly affected by pyrazoles and pyrazolates acting as coplanar ligand. The π interactions tied multiple pyrazoles and pyrazolates together around the nickel metal to cause reaction results.
  Another π metal interaction directly involved with catalysis involves π stacking. Ferrocene is the standard example where the metal (iron) is trapped in between two cyclopentadienyl ligands. These interactions are commonly referred to as sandwich compounds.
  Specific research
  Due to reasons explained earlier in the article, the bonding between a nucleophilic olefin and an electrophilic palladium(II) leaves olefin susceptible to nucleophilic attack. This is true if the olefin is coordinated around Pd as the corner of a square planar complex or as the side of a cationic 18-electron Pd complex. In both cases electron donating groups on the olefin stabilize the complex, but anionic electron donors actually destabilized the complex in the case of the 18-electron Pd complex. The authors of this research proposed that when the olefin π bond is aligned on the side of the square planar Pd complex, the π* backfilling of electron density from Pd to olefin is enhanced because the more electron withdrawing orbital of the π complex can overlap better with the electron donating orbital of Pd.