Geometric and electronic structure analyses on three Au42(SR)26 isomers

Abstract

In this paper, we present the geometric and electronic structure analyses of three Au42(SR)26 isomers based on a combination of grand unified model (GUM), ring model, superatom network model, and density functional theory calculations. Structural decompositions, Au–Au and Au–S distances, Wiberg bond orders, density of states, composition of the frontier orbitals, and origin of the optical absorption spectra are presented and discussed in detail. The structural decomposition of the Au cores of the three isomers into eight tetrahedral Au4 elementary blocks based on GUM shows that the isomeric mechanism of the three isomers can be ascribed to core and complex isomerism. Inspection of Au–Au and Au–S distances reveals the key role of the aurophilic interactions in the stability of the three Au42(SR)26 isomers. Furthermore, by analyzing the composition of the frontier orbitals, the origin of the optical absorption spectra of the three isomers is attributed to the sp → sp transition. Overall, the geometric and electronic structure analyses of the three Au42(SR)26 isomers illustrate the inherent structure–property correlations among these isomers.