Enhancing catalytic activity in hydrogenation reaction by decorating Pd nanoparticles with N-heterocyclic carbenes

A method for the preparation of a heterogeneous palladium catalyst is proposed, which allows controlling the size and activity of the resulting particles. Materials prepared from Pd<sub>2</sub>(dba)<sub>3</sub> by deposition at 80 °C showed high catalytic activity in the reaction of diphenylacetylene hydrogenation. The catalytic activity can be further enhanced by preactivation involving the addition of the carbene ligand 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) into the reaction mixture.