Structural predictions of thiolate-protected gold nanoclusters via the redistribution of Au–S “staple” motifs on known cores

Abstract

Four new atomic structures of thiolate-protected gold nanoclusters, namely, Au₂₇(SR)₂₀⁻, Au₃₂(SR)₂₁⁻, Au₃₄(SR)₂₃⁻, and Au₃₆(SR)₂₅⁻, were predicted via the redistribution of Au–S “staple” motifs on the known Au₁₃ core from experimentally determined Au₂₃(SR)₁₆⁻ and the Au₂₀ core from crystallized Au₃₀(SR)₁₈. Density functional theory calculations show that these structures have large highest occupied molecular orbital–lowest unoccupied molecular orbital gaps and positive vibrational frequencies, indicating their high stabilities. Furthermore, a series of more stable theoretical structures were predicted by introducing triply coordinated μ₃-sulfido (μ₃-S) motifs to the cores of Au₂₇(SR)₂₀⁻, Au₃₂(SR)₂₁⁻, Au₃₄(SR)₂₃⁻, and Au₃₆(SR)₂₅⁻. These predicted structures can further confirm the effectiveness and rationality of the ligand-binding strategy for the structural prediction of thiolate-protected gold nanoclusters by redistributing the Au–S “staple” motifs on known cores.