ON THE INTERACTION OF PALLADIUM WITH OLEFINIC SYSTEMS

We have performed all electron Hartree–Fock gradient calculations and geometry optimizations on systems composed of one to three palladium atoms and: CH3 cation and anion, C2H4, C2H3NH2, C4H4, NH3, and (NH3) + (C2H4). Several basis set considerations are discussed and the binding energies of Pd to these small molecules are reported. We find the counterpoise correction to the binding energies of these systems to be large. We also present MP2 calculations of the palladium binding energy with a large uncontracted palladium spd basis set in the PdC2H4 and PdNH3 systems. The binding interaction between ethylene and palladium results in a mixing of the 4d–π* and 5s–π orbitals, and, is dissociative to the ethylene. The palladium‐butadiene and palladium‐cyclobutene relative stabilites and structures are interesting since these molecules could form from acetylene on a palladium surface. We find the Pd‐butadiene cyclic structure to be 43 kcal/mol more stable than the Pd‐cyclobutene product. Copyright © 1990 John Wiley & Sons, Inc.