Atomically Precise Multimetallic Semiconductive Nanoclusters with Optical Limiting Effects

Abstract For the first time, multinuclear noble‐metal clusters have been successfully stabilized by Ti‐oxo clusters. Two unprecedented Ag 6 @Ti 16 ‐oxo nanoclusters with precise atomic structures were prepared and characterized. The octahedral Ag 6 core has strong Ag−Ag bonds (ca. 2.7 Å), and is further stabilized by direct Ag−O−Ti coordination interactions. Moreover, as a result of different acidic/redox conditions in synthesis, the Ag 6 core can adopt diverse geometric configurations inside the Ti 16 ‐O shell. Correspondingly, structural differences greatly influence their optical limiting effects. The transmittance reduction activity of the clusters towards 532 nm laser shows a nearly linear concentration dependence, and can be optimized up to about 43 %. This work not only opens a new direction for multimetallic semiconductive nanoclusters with interesting optical properties, but also provides molecular models for important noble‐metal/TiO 2 heterogeneous materials.