On the variation of cluster core characteristics by an endohedral atom. Shape variation in 8-ce [EAu4(PPh3)4]2+ (E = N, P, As, Sb) clusters

Abstract

Atomically precise gold superatoms have attracted interest owing to their suitable use as building blocks for cluster-assembled materials, favoring ordered structures with advanced properties. In this sense, expanding their versatility is a relevant issue for controlling their properties and retaining a specific nuclearity. Interestingly, the reported structure for isoelectronic [Au₄N(PPh₃)₄]⁺ and [Au₄Sb(PPh₃)₄]⁺ clusters denotes two contrasting shapes featuring a tetrahedral and square pyramidal structure, respectively. Herein, we further explore the [Au₄E(PPh₃)₄]⁺ (E = N, P, As, Sb) series in order to evaluate energetic and structural factors determining the overall shape. Our results show a favorable [Au₄(PPh₃)₄]⁴⁺/E³⁻ interaction energy, predicting particular patterns in their UV-vis spectrum. Thus, the use of dopant atoms is enabled to vary the core shape and, in turn, to modify the cluster properties, which serve as a structural control, in addition to ligand-based and size approaches.