Novel two-dimensional tin sulfide networks: Preparation and structural characterization of Sn₄S₉[(C₃H₇)₄N]₂ and Sn₄S₉[(C₃H₇)₄N] · [(CH₃)₃NH]

A new framework with the composition [Sn₄S₉]^2- has been synthesized hydrothermally in the presence of tetrapropylammonium (TPA) hydroxide. The structures of two compounds possessing this framework, Sn₄S₉[(C₃H₇)₄N]₂ (1) and Sn₄S₉[(C₃H₇)₄N] · [(CH₃)₃NH] (2), have been solved using single-crystal X-ray diffraction data. Both crystallize in the space P 2₁/n (Z = 4) with unit cell parameters a = 15.497(5) Å, b = 15.826(4) Å, c = 18.594(5) Å, β = 110.40(1)° for (1), and a = 14.832(4) Å, b = 18.612(6) Å, c = 15.039(6) Å, β = 96.90(3)° for (2). These compounds are layered with organic cations accommodated between Sn-S sheets containing apertures composed of 16 SnS₅ and SnS₄ polyhedra. Both materials contain TPA⁺ cations, and (2) also incorporates trimethylammonium cation, a breakdown product of TPA.