Modeling of ligand induced changes in the magneto-structural properties of Pd13 cluster

Palladium nanostructures are widely used as catalyst of many organic reactions1 and present intriguing and controversial magnetic properties. Since the direct experimental determination of ground state structure for small transition metal clusters is difficult, theory and first-principles calculations, such as density functional theory (DFT), have been used extensively to reveal the interplay between geometric and electronic structure.
We present a theoretical study at the DFT/B3LYP level on three selected geometric arrangements for the Pd13 cluster with particular emphasis on the effects of thiolate and phosphine based ligands on their magneto-structural properties.
The results point out that the interactions with ligands can change the relative stability of different structures of the metallic core, leading to the stabilization of the more compact icosahedral shape with respect to other bi-layer structures which are more stable in the free standing cluster. Beyond this structural evolution, the interactions with the ligand shell strongly modify also the electronic and magnetic properties of the metal core. In particular, both thiolate and phosphine ligands quench the high spin state that characterized the magnetic ground state of the bare Pd13 cluster, but while the interaction with phosphine quench the magnetic moment completely, the thiol-capped particles retain a permanent magnetic moment even when they are saturated by the ligand molecules.
Our study suggests that different ligands can be effectively used to tune electronic and magnetic properties of Pd nanoparticles in view of the design and experimental realization of logic nano devices and intelligent sensors.