Density functional studies of the electronic and geometric structures of Pt₃⁺, Pt₃O⁺, Pt₃O₂⁺ and Pt₃CH₄⁺

The lower energy electronic states of Pt₃⁺, Pt₃O⁺, Pt₃O₂⁺ and Pt₃CH₄⁺ have been determined with the hybrid density functional B3LYP method. The Pt₃⁺ geometries are found to be close to equilateral triangle. The oxygen atom is found to 3 bind preferentially bidentately to two Pt atoms in the Pt₃⁺ 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 Pt₃⁺-O₂ binding energy, on the other hand, is calculated to be only 14 kcal/mol, with O₂ bound to a single Pt atom in an end-on manner. The Pt₃⁺-O and Pt₃⁺-O₂ binding energies imply that Pt₃⁺ can split the O-O bond. The methane molecule is found to bind Pt₃⁺ 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, O₂ and CH₄) that could affect their subsequent reactions.