Platinum-Gold Cluster Compounds

Abstract

Platinum—gold cluster compounds with metal frames, consisting of a central Pt surrounded by 5–9 Au atoms have structures and reactivity, governed by a simple 16–18 electron counting rule, like in the case of mononuclear Pt compounds. Structures are toroidal (16 electrons) or spheroidal (18 electrons). The frames are amphoteric in acid—base reactions, preferring CO and RNC as nucleophiles and Au⁺ Ag⁺ and Cu⁺ as electrophilic agents. β-H transfer to form hydrides and oxidative addition, notably with Hg₂X₂ to form Pt Au₈Hg₂ are known. Clusters with 17 electrons can be prepared by electrochemical reduction and they are relatively stable. Some similarities in structure and reactivity with Pt—Au alloys are shown.

Key Words:

• platinum—gold clusters
• amphoteric metal clusters
• oxidative addition on metal clusters
• metal cluster reactivity