Three-dimensional organic–inorganic hybrid sodium halide perovskite: C(4)H(12)N(2)·NaI(3) and a hydrogen-bonded supra­molecular three-dimensional network in 3C(4)H(12)N(2)·NaI(4)·3I·H(2)O

The rational selection of ligands is vitally important in the construction of new organic–inorganic hybrid three-dimensional perovskite complexes. As part of an exploration of perovskite-type materials, two new Na–I compounds based on the piperazine ligand, namely poly[piperazinediium [tri-μ-iodido-sodium]], {(C(4)H(12)N(2))[NaI(3)]}(n), 1, and catena-poly[tris­(piperazinediium) [[tri­iodido­sodium]-μ-iodido] triiodide monohydrate], {(C(4)H(12)N(2))(3)[NaI(4)]I(3)·H(2)O}(n), 2, have been synthesized by adjusting the stoichiometric ratio of sodium iodide and piperazine, and were characterized by single-crystal X-ray diffraction. In the crystal structures of 1 and 2, each Na(I) cation is linked to six I atoms, but the compounds show completely different configurations. In 1, the structure includes a perovskite-like array of vertex-sharing NaI(6) octa­hedra stretching along the direction of the three axes, and each piperazinediium dication is enclosed in the NaI(3) perovskite cage. However, in 2, each Na(I) atom bridges a single I atom to form a one-dimensional linear chain, and complex inter­molecular hydrogen bonds connect these one-dimensional chains into a three-dimensional supra­molecular network.