Threefold Collaborative Stabilization of Ag14-Nanorods by Hydrophobic Ti16-Oxo Clusters and Alkynes: Designable Assembly and Solid-State Optical-Limiting Application.

Ag nanoclusters have received increasing attention due to their atomically precise and diverse structures and intriguing optical properties. Nevertheless, the inherent instability of Ag nanoclusters has seriously hindered their practical applications. In this work, for the first time, Ag cluster is collaboratively protected by hydrophobic Ti-oxo cluster and alkyne ligand. At the beginning, a pyramidal Ag5 cluster terminated with tBuC≡C- and CH3CN was inserted into the cavity of a Ti8-oxo nanoring to form Ag5@Ti8. To further overcome the instability of acetonitrile terminated silver site, such two Ag5@Ti8 clusters could sandwich an Ag4 unit to form Ag14-Nanorod@Ti16-oxo-Nanoring (Ag14@Ti16) in the absence of CH3CN, which is peripherally protected by fluorophenyl groups and alkyne caps. As a result, such threefold protected (hydrophobic fluorinated organic layer, Ti-O shell and terminal alkyne ligands) Ag14@Ti16 exhibits superhydrophobicity and excellent ambient stability, enabling it with solid-state optical limiting characteristics. The success of this work provides meaningful guidance for improving the stability of metallic clusters to extend their future practical applications.