Evidence of New Fluorinated Coordination Compounds in the Composition Space Diagram of FeF₃/ZnF₂–Hamtetraz-HF_aq System

The exploration of the composition space diagram of the FeF₃/ZnF₂–Hamtetraz-HF_aq system (Hamtetraz = 5-aminotetrazole) by solvothermal synthesis at 160 °C for 72 h in dimethylformamide (DMF) has evidenced five new hybrid fluorides (1–5); the structures are characterized from single crystal X-ray diffraction data. [Hdma]­·(ZnFe^III(H₂O)₄F₆) (1) and [Hdma]­·[Hgua]₂­·(Fe^IIIF₆) (2) contain anionic inorganic chains (1) or isolated octahedra (2) weakly hydrogen bonded (Class I hybrids) to dimethylammonium (Hdma) and/or guanidinium (Hgua) cations which are produced from the tetrazole ligand and solvent decomposition. [Hdma]₂­·[Hgua]­·[NH₄]­·[ZnFe^IIIF₅(amtetraz)₂]₂ (3), [Hdma]₂­·[Zn_1.6Fe^II_0.4Fe^IIIF₆­(amtetraz)₃] (4), and [Hdma]­·[Zn₄F₅(amtetraz)₄] (5) are considered as Class II hybrids in which the (amtetraz)⁻ anions are strongly linked to divalent metal cations via N–M bonds. In 3, _∞{[NH₄]­·[ZnFe^IIIF₅­(amtetraz)₂]₂} layers are separated by [Hdma]⁺ and [Hgua]⁺ cations. 4 and 5 exhibit three-dimensional (3D) hybrid networks that contain small cavities where [Hdma]⁺ cations are inserted. A porous 3D metal–organic framework intermediate is evidenced from the thermogravimetric analysis and X-ray thermodiffraction of 5.