Rational design of the 6 e thiolate-protected Au24(SR)18 nanocluster.

The growth mechanism of thiolate-protected gold nanoclusters (AuNCs) has been advanced, but precise crystal structure information is lacking. Recent mass spectrometry and nuclear magnetic resonance analysis experiments traced the Au₂₄(SR)₁₈ cluster as a non-negligible byproduct intermediate during the reaction between [Au₂₅(SR)₁₈]⁻, the flagship cluster of the remarkable nanocluster ship, and Au₂₅(SR)₁₉, a cluster with 25 Au atoms but featuring a completely different structure than the [Au₂₅(SR)₁₈]⁻ cluster. However, the precise structure of the Au₂₄(SR)₁₈ cluster is unknown. In this study, a total of seven Au₂₄(SR)₁₈ isomers were constructed using the grand unified model. Density functional theory calculations demonstrated that two of them could be considered quasi-degenerate suggesting that both might coexist in experiments. Geometrical features, electronic structures, and absorption spectra were calculated for potential future comparisons. This work contributes to fully interpreting the growth mechanism of AuNCs. [ABSTRACT FROM AUTHOR]