Atomically Precise Site-Specific Tailoring and Directional Assembly of Superatomic Silver Nanoclusters

摘要

Convenient generation of stable superatomic silver clusters and their systematic site-specific tailoring and directional assembly present an enduring and significant challenge. In this work, we prepared a face-centered cubic (fcc) array of Ag_(14) superatoms protected by face-capping 1,2-dithiolate- o -carborane (C_(2)B_(10)H_(10)S_(2)) ligands, each produced from 1-thiol- o -carborane in crystallization with simultaneous reduction of Ag~(+) to Ag~(0). We find that the corner N-donor ligands contribute predominately to the stability and luminescence of the Ag_(14) superatom. As the first-formed nanocluster [Ag_(14)(C_(2)B_(10)H_(10)S_(2))_(6)(CH_(3)CN)_(8)]·4CH_(3)CN ( NC-1 ) with labile vertex-coordinated CH_(3)CN ligands is highly unstable, monodendate pyridine ligands were used to replace these CH_(3)CN species site-specifically, giving [Ag_(14)(C_(2)B_(10)H_(10)S_(2))_(6)(pyridine/ p -methylpyridine)_(8)] ( NCs-2,3 ) in gram scale with its core structure intact, which features ultrastability up to 150 °C in air. Moreover, using bidentate N-containing ligands to bridge the superatomic Ag_(14) building blocks, we constructed an unprecedented hierarchical series of 1D-to-3D superatomic silver cluster-assembled materials ( SCAM-1,2,3,4 ), and SCAM-4 is air-stable up to 220 °C. Furthermore, this series of stable solid-state superatomic-nanocluster materials exhibit tunable dual emission with wide-range thermochromism. The present study constitutes a major step toward the development of ligand-modulation of the structure, stability, assembly, and functionality of superatomic silver nanoclusters.