A Unique Pair: Ag40 and Ag46 Nanoclusters with the Same Surface but Different Cores for Structure-Property Correlation.

Understanding the optical properties of nanoclusters is one of the central tasks in fundamental research. In this work, two new Ag nanoclusters that have distinctly different cores but a common protecting shell are achieved, including [Ag40(2,4-DMBT)24(PPh3)8] and [Ag46(2,5-DMBT)24(PPh3)8]2+. Significantly, the Ag40 nanocluster comprises a simple cubic core of Ag8, which is observed experimentally in the field of metal materials for the first time. Using the Ag40 and Ag46 nanoclusters as a unique pair, we have investigated the effect of core structure on the optical absorption properties of these nanoclusters. The compact core-shell in Ag46 makes the frontier orbitals highly degenerate, whereas the loose core-shell of Ag40 leads to much less degeneracy in the frontier orbits. Overall, this work reveals that the core packing mode plays a significant role in determining the optical properties of metal nanoclusters. The new materials with controlled crystalline phases also hold promise in other applications.