Size Exclusion Chromatography for Semipreparative Scale Separation of Au38(SR)24 and Au40(SR)24 and Larger Clusters

Size exclusion chromatography (SEC) on a semipreparative scale (10 mg and more) was used to size-select ultrasmall gold nanoclusters (<2 nm) from polydisperse mixtures. In particular, the ubiquitous byproducts of the etching process toward Au-38(SR)(24) (SR, thiolate) clusters were separated and gained in high monodispersity (based on mass spectrometry). The isolated fractions were characterized by UV-vis spectroscopy, MALDI mass spectrometry, HPLC, and electron microscopy. Most notably, the separation of Au-38(SR)(24) and Au-40(SR)(24) clusters is demonstrated.