The thesis focuses on the modification of atomically precise Au38(SR)24 nanocluster to clarify its dynamic nature and to fine-tune its catalytic activity. Two Pd atoms and mutiple Ag atoms doped Au38 were synthesized, separated and their dopant location were determined. The flexibility of Au38 increased upon Pd and Ag doping due to the change in electronic structural properties and the weak surface Ag-S bond introduced, respectively. Flexibility of metal core was also revealed by the redistribution of the Ag atoms between AgxAu38-x and Au38, where the collision between the clusters is suggested to be the origin of the Ag migration. Modification of the Au38 nanocluster surface by thermal pretreatment and support material enabled structure-activity correlation in cyclohexane oxidation.