Alloying and Dealloying of Au18Cu32nanoclusters at Precise Locationsviacontrolling the Electronegativity of Substituent Groups on Thiol Ligands

The doping site of metals in an alloy nanocluster plays a key role in determining the cluster properties. Herein, we found that alloying engineering was achieved by replacing Cu at specific positions in the second layer Cu20 shell of the [Au18Cu32(SR-O)36]2- or [Au18Cu32(SR-F)36]3- (SR-O = -S-PhOMe; SR-F = -SC6H33,4F2) nanocluster with Au to generate a core-shell [Au20.31Cu29.69(SR-O)36]2- protected by mercaptan ligands with electron-donating substituents, which could be stable obtained compared with the alloyed nanocluster with electron-withdrawing substituent ligands. Moreover, dealloying engineering was accomplished by an electron-withdrawing substituent ligand exchange strategy (i.e., [Au18Cu32(SR-F)36]2-). The abovementioned reaction was analyzed using single-crystal X-ray crystallography, electrospray ionization mass spectrometry, and X-ray photoelectron spectroscopy and monitored via time-dependent ultraviolet-visible absorption spectroscopy. This reversible and precise location of alloying and dealloying provides the possibility for studying the relationship between the structure and properties of nanoclusters at the atomic level.