Two Electron Reduction: From Quantum Dots to Metal Nanoclusters

The
quantum dots (QDs) and metal nanoclusters (MNCs) have recently
attracted increasing interest due to their intriguing physical–chemical
properties. Nevertheless, the inherent correlations between them have
rarely been explored. In this study, we successfully achieved the
conversion of the silver QDs ([Ag62S13(SBut)32]4+) to silver MNCs ([Ag62S12(SBut)32]2+) via the
electrochemical reduction method. A key intermediate could be obtained
by setting the voltage at (−0.6) V, and its atomic structure
has been determined to be [Ag62S13(SBut)32]2+ by single crystal X-ray crystallography.
After that, the centroid S atom in the Ag14S cubic core
can be extruded out of the clusters through the window via an energy
favorable route during the reducing process which will be reported
for the first time. The detailed conversion process and the accompanying
changes of optical properties were studied. Our work revealed a unique
case that QDs could be converted to MNCs.