N-Heterocyclic Thione-Protected Ag₄ Tetrahedra and Ag₈ 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: [Ag₄(2-TBI)₆(SO₄)₃]^2- (Ag) and [Br@Ag₈(2-TBI)₁₂(SO₄)₂]³⁺ (Ag) (2-TBI = 2-thiobenzimidazol), which cocrystallize to form cluster-based molecular crystals with a CaF₂-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.