Isolation of the Au 145 (SR) 60 X compound (R = n -butyl, n -pentyl; X = Br, Cl): novel gold nanoclusters that exhibit properties subtly distinct from the ubiquitous icosahedral Au 144 (SR) 60 compound

• Published in: Nanoscale 2021-09, Vol.13 (36), p.15394-15402
• Main Authors: Dainese, Tiziano, Antonello, Sabrina, Bonacchi, Sara, Morales-Martinez, Daniel, Venzo, Alfonso, Black, David M., Mozammel Hoque, M., Whetten, Robert L., Maran, Flavio
• Format: Article
• Language: English
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/D1NR04745K

We report the identification and quantitative isolation of Au 145 (SR) 60 X (R = n -butyl, n -pentyl; X = halide) along with elucidation of key properties as compared to the corresponding ubiquitous chiral-icosahedral Au 144 (SR) 60 cluster known to have a central vacancy. The stoichiometries were assessed by electrospray mass spectrometry (ESI-MS) at isotopic resolution, and induced dissociation patterns indicate the ‘extra’ (Au,Br) atoms are strongly bound components of these structures. Voltammetric and spectroscopic characterization reveals Au 145 (SR) 60 X behaviors that are qualitatively similar to yet fascinatingly distinct from those of Au 144 (SR) 60 . ( 1 H, 13 C)-NMR spectra clearly show how both Au 145 (SR) 60 X and Au 144 (SR) 60 are capped by 12 distinct ligand types of 5-fold equivalence, as was recently established for Au 144 (SR) 60 capped by shorter ligands, demonstrating that this novel cluster shares the same chiral-icosahedral motif. Intriguingly, Au 145 (SR) 60 X is strongly near-IR luminescent, whereas under comparable conditions Au 144 (SR) 60 barely emits. The photoluminescence pattern of Au 145 (SR) 60 X is very similar to that observed for Au 25 (SR) 18 , which contains the Au 13 core. The combined results are interpreted as consistent with neutral Au 145 (SR) 60 X as a diamagnetic species, electronically and structurally similar to the corresponding Au 144 (SR) 60 compounds.