Density functional studies of the electronic and geometric structures of Pt 3+, Pt 3O +, Pt 3O 2+ and Pt 3CH 4+

Abstract

The lower energy electronic states of Pt 3 +, Pt 3O +, Pt 3O 2 + and Pt 3CH 4 + have been determined with the hybrid density functional B3LYP method. The Pt 3 + geometries are found to be close to equilateral triangle. The oxygen atom is found to bind preferentially bidentately to two Pt atoms in the Pt 3 + plane with a binding energy of 72 kcal/mol. There are two less exothermic binding modes: tridentate above the plane and monodentate in the plane. The Pt 3 +–O 2 binding energy, on the other hand, is calculated to be only 14 kcal/mol, with O 2 bound to a single Pt atom in an end-on manner. The Pt 3 +–O and Pt 3 +–O 2 binding energies imply that Pt 3 + can split the O–O bond. The methane molecule is found to bind Pt 3 + through two Pt…HC interactions on a single Pt atom with the binding energy of 17 kcal/mol. There are distinct differences in the cluster–complex charge distributions depending on the substrate (O, O 2 and CH 4) that could affect their subsequent reactions.