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.