INFLUENCE OF HALOGEN NATURE ON THE ADSORPTION ABILITY OF ARYL HALIDES ON PALLADIUM CLUSTERS

Abstract

In this paper, the density functional theory calculations were carried out in order to find the adsorption energies of a benzene ring on small Pd0 clusters consisting of four or nine atoms. The adsorption of benzene on palladium clusters was found to result in a noticeable energy gain of the system: -146 kJ/mol in the case of Pd4, and -117 kJ/mol in the case of Pd9. The adsorption energies of chloro-, bromo- and iodoanisole on Pd4*C6H6 were also calculated. The adsorption of iodoanisole was characterized by the highest energy gain of the system (-278 kJ/mol) and occurred dissociatively without activation, that fundamentally distinguished it from chloro- and bromoanisole. The data obtained can be used to explain the differences in the behavior of catalysts based on hyper-cross-linked polystyrene in cross-coupling reactions of various aryl halides and phenylboronic acid, and also the fact that aryl iodides can favor the formation of homogeneous forms of palladium.

Keywords

• palladium
• clusters
• aryl halides
• suzuki cross-coupling
• density functional theory