Effect of the synthesis temperature on the dimensionality of hybrid fluorozincates

Abstract

Abstract A series of new hybrid fluorozincates incorporating 5-aminotetrazole (Hamtetraz) is obtained from a same starting mixture of ZnF2, HF solution and Hamtetraz in acetronitrile at different synthesis temperatures. The structures, determined by single crystal X-ray diffraction, exhibit various networks with dimensionalities that increase as a function of the synthesis temperature. At 120 °C, two phases, ZnF2(H2O)(Hamtetraz) (1) and ZnF2(Hamtetraz)2 (2), coexist and display 1D infinite chains. ∞[ZnN2F2O] chains are built up from ZnN2F3(H2O) octahedra linked by opposite fluorine corners in 1, while ∞[ZnN2F2] chains of edge sharing ZnN2F4 octahedra are found in 2. At 130 °C, dense layers appear in Zn3F5(H2O)2(amtetraz) (3); they result from the condensation of ∞[ZnF3N2] and ∞[ZnF2NO] chains by fluorine corners to form a neutral 2D network. At 140 °C, [NH4]·(Zn4F5(amtetraz)4)·3H2O (4) presents an anionic 3D network containing small cavities in which water molecules and ammonium cations are inserted. The thermal behavior of the coordination polymers 3 and 4 is studied by TGA analysis and X-ray thermodiffraction; an intermediate phase is observed during the decomposition of 4.