N -Heterocyclic Thione-Protected Ag 4 Tetrahedra and Ag 8 Cubes Cocrystallized in a Single Crystal.

Polynuclear silver clusters have attracted intensive attention in the academic community owing to their rich physicochemical properties. The development of thione-protected silver clusters has been lagging behind the well-explored thiolate-protected silver-sulfide clusters. Herein, we report two N -heterocyclic thione-protected silver clusters: [Ag 4 (2-TBI) 6 (SO 4 ) 3 ] 2- ( Ag 4 ) and [Br@Ag 8 (2-TBI) 12 (SO 4 ) 2 ] 3+ ( Ag 8 ) (2-TBI = 2-thiobenzimidazol), which cocrystallize to form cluster-based molecular crystals with a CaF 2 -type structure. The cocrystal shows high thermal stability in air. Notably, the two cluster-based layers are alternately assembled to exhibit a unique k -vector-differential crystallographic arrangement. This work may lay a foundation for synthesis of atomically precise and stable silver clusters using readily available N -heterocyclic thione ligands.