Two new selenidostannates with a [Sn₃Se₇]_n²ⁿ⁻ layer from the imidazolium-based ionic liquids: The role of (Bzmim)⁺ and aggregated cation of [(Emim)₃Cl]²⁺

Herein, we report on the syntheses, crystal structures, and optical properties of two new selenidostannates, namely, [Emim]₅[Sn₃Se₇]₂Cl (1, Emim = 1-ethyl-3-methylimidazolium) and [Bzmim]₂[Sn₃Se₇] (2, Bzmim = 1-benzyl-3-methylimidazolium). The ionic liquids (ILs) of [Emim]Cl with a short ethyl chain and [Bzmim]Cl with a bulky substituent benzyl group were used in the syntheses of compounds 1 and 2, respectively. Although both the structures feature an anionic lamellar [Sn₃Se₇]_n^2n– layer, the packing of the layers are dramatically different; such structural diversity may be ascribed to the difference of structure-directing cations incorporated in between the layers, that is [(Emim)₃Cl]²⁺ aggregates in 1 and bulky [Bzmim]⁺ in 2, respectively.