A Chemical View of the Giant Au102(SR)44 (SR = P‐Mercaptobenzoic Acid) Cluster: Metalloid Aluminum and Gallium Clusters as Path Making Examples of This Novel Type Open Our Eyes for Structure and Bonding of Metalloid Aun(SR)m (n > m) Clusters

Abstract

AbstractThe outstanding position of metalloid clusters as intermediates between the bulk metals and bulk salts on the one hand and of naked metal atom clusters and salt‐like clusters on the other hand is described first. Subsequently, a different more chemical description of structure and bonding of a recently published gold‐thiolate Au102(SR)44 cluster based on the results of aluminum‐/gallium clusters is presented., This comparison shows that there is no principal but only a gradual difference between the Au102 cluster and the large number of metalloid aluminum‐/gallium clusters: both have a metalloid character, i.e. there is a highly mixed valent bonding situation of the metal atoms involved. Therefore these clusters represent a highly complex system and are far from being only nanoscaled metal particles surrounded by a shell of protecting ligands. In detail this comparison shows that the metalloid gold and the aluminum‐/gallium clusters are similar in the center, as these metal‐metal interactions are energetically similar to those of the metallic solid state. However, there are significant differences between metalloid gold and aluminum‐/gallium clusters in the outer regions since the interactions of the metal atoms of the outer shell with the ligands are different: i.e. in contrast to strong Al–ligand interactions there are weaker Au–ligand bonds. Furthermore it will be shown that the special Au–ligand interactions of the Au102 cluster, which have been discussed as a novel staple motif so far, might be better attributed to the well established structural chemistry of AuI species. To sum up, structure and bonding of metalloid gold clusters, even if they have not been structurally characterized in detail, like the well‐known Schmid cluster, show that they belong to the family of metalloid clusters like the large number of aluminum‐/gallium ones; i.e. they have to be seen in a novel light. Consequently, these conclusions may have a large impact on the great variety of investigations of surface reactions between crystalline gold surfaces and sulfur‐containing molecules.