Oxidation-Induced Transformation of Eight-Electron Gold Nanoclusters: [Au23(SR)16]- to [Au28(SR)20]0

Here we report an oxidation-induced transformation of [Au-23(S-cC(6)H(11))(16)](-)TOA(+) (S-c-C6H11: cyclohexanethiolate; TOA: tetraoctylammonium) to the [Au-28(S-c-C6H11)(20)](0) nanocluster by H2O2 treatment under ambient conditions. This is the first example of oxidation-induced transformation of one stable size to another with atomic precision. The product was crystallized and analyzed by X-ray crystallography. Further insights into the transformation process were obtained by monitoring the process with optical spectroscopy and also by electrochemical analysis. This work adds a new dimension to the recently established transformation chemistry of nanoclusters that involves size and structure transformations.