Partially Poisoned Pd Nanoparticles for Selective Hydrogenation and/or Isomerization of Olefins

摘要

Colloidal Pd nanoparticles (PdNPs) capped with alkanethiolate ligands exhibit an excellent selectivity toward the isomerization of terminal alkenes to internal alkenes and allylic alcohols to carbonyls in organic solvents. PdNPs are also found to be selective for the hydrogenation of activated alkenes and the mono-hydrogenation of dienes and trienes. The high selectivity of Pd nanoparticles is steered from the partial poisoning by thiolate ligands. The controlled electronic properties of the Pd surface limit the formation of Pd-alkene adducts (or intermediates) necessary for (additional) hydrogenation. The high activity of colloidal Pd nanoparticle catalysts allows the reactions to be completed under atmospheric pressure and at room temperature. These homogeneously soluble and stable PdNP catalysts offer the advantages of facile separation and multiple recycling without significant losses in activity and selectivity.