New 2D and 3D Coordination Polymers by Dehydration of 1 ∞ [ M II ( tF ‐BDC)(H 2 O) 4 ] ( M II = Zn 2+ , Co 2+ , Ni 2+ and tF ‐BDC 2– = Tetrafluoroterephthalate)

By dehydration of the known coordination polymers 1 ∞ [ M II ( tF ‐BDC)(H 2 O) 4 ] ( M II = Co 2+ , Zn 2+ and tF ‐BDC 2– = tetrafluoroterephthalate) the homoleptic anhydrous coordination networks 3 ∞ [M II ( tF ‐BDC)] were obtained as polycrystalline powders. Their crystal structures ( C 2/ c, Z = 4) were solved and refined by means of synchrotron powder diffraction data. These structures are characterized by [ M II O 4 ] tetrahedra, which are connected by the tF ‐BDC 2– linkers to form a 3D non‐porous coordination network. The dehydration leads to a change from a [ M II O 6 ] octahedral coordination in the hydrate to a tetrahedral coordination sphere in the anhydrous compound. For the cobalt compounds this leads to a color change from pale rose to deep blue upon heating and dehydration, which was analyzed by means of UV/Vis/NIR spectroscopy and measurements of the magnetic susceptibilities. In contrast, 1 ∞ [Ni II ( tF ‐BDC)(H 2 O) 4 ] can only partly be dehydrated to form 2 ∞ [Ni II ( tF ‐BDC)(H 2 O) 2 ] ( P 1 , Z = 1) with retention of the octahedral [Ni II O 6 ] coordination in both compounds. At higher temperatures the tF ‐BDC 2– linker starts to decompose, before a complete dehydration can take place.