Electron counting and bonding patterns in assemblies of three and more silver-rich superatoms

Abstract

DFT calculations were carried out on a series of cluster cores, the framework of which being made of the condensation of several Pt@Ag12 centered icosahedra. Icosahedra condensations through vertex-sharing, face-sharing...

Looking at platinum carbonyl nanoclusters as superatoms

“…Non-spherical metal group 11 nanoclusters, the structure of which can be described as resulting from the assembly of several pseudospherical individual units (most often icosahedral) are becoming quite common. 33,51,52,[86][87][88][89][90] In such assemblies, the icosahedral units share either a vertex, a triangular face or are interpenetrated in such a way they share a pentagonal face and its two capping atoms. Such assemblies of individual superatomic units can be viewed as "supermolecules", with supermolecular orbitals looking like molecular orbitals, and electron counts related to that of simple main-group molecules, depending on their fusion extent, in the same way as molecule electron counts depend on bond orders (BOs).…”

“…Such assemblies of individual superatomic units can be viewed as "supermolecules", with supermolecular orbitals looking like molecular orbitals, and electron counts related to that of simple main-group molecules, depending on their fusion extent, in the same way as molecule electron counts depend on bond orders (BOs). 52,91,92 Concerning group 11 nanoclusters made of two fused centred icosahedra, vertexsharing systems have favored superatomic closed-shell electron counts of 16 or 14, i.e., equivalent to Ne 2 (BO = 0) or F 2 (BO = 1), respectively. 90,93 Face-sharing icosahedra can also have a favored count of 14 93 whereas interpenetrated icosahedra can display a favored count of 10, i.e., equivalent to N 2 (BO = 3).…”

“…This unexpected electron count was also previously predicted for related Ag-rich structures. 52 It is of course possible to imagine various types of linear assemblies made of several fused superatomic units. For example, assuming the Pt 23 core made of two face-sharing centred icosahedra, with terminal carbonyls on each of the 21 peripheral metal atoms (Fig.…”

“…This simple electron counting scheme works perfectly in the case of ligated group 11 metal clusters and indeed, most of them can be described as closed-shell superatoms 38–45 or closed-shell assemblies of superatoms ( supermolecules ). 33,46–54…”

“…This simple electron counting scheme works perfectly in the case of ligated group 11 metal clusters and indeed, most of them can be described as closedshell superatoms [38][39][40][41][42][43][44][45] or closed-shell assemblies of superatoms (supermolecules). 33,[46][47][48][49][50][51][52][53][54] In the case of group 10 ligated nanoclusters, it turns out that the above methodology for counting electrons does not apply so staightforwardly. Thus, this sizeable structural chemistry appears to stand outside the superatom concept and remains mostly unexplained.…”