Coordination Polymers with Tetrafluoroterephthalate as Bridging Ligand

Seven nonporous coordination polymers with tetrafluoroterephthalate (tfBDC(2-)) as a bridging ligand were synthesized and structurally characterized. Homoleptic (3)(infinity) [Tl-2 (tfBDC)] (p (1) over bar, Z = 1, 1) contains six-coordinated Tl centers, which are connected by the tfflDC(2-) ligand to form a three-dimenSional (3D) network. Upon heating it decomposes at approximately 200 degrees C. Nine-coordinated PbO9 polyhedra are found in (2) (infinity)[Pb(tfBDC)(H2O)(3)]center dot 1/2 H2O (P (1) over bar, Z = 1, 2), which forms a layer-like structure. These layers are held together by hydrogen bonds involving water molecules. These water molecules are released by heating to 70-100 degrees C. (1)(infinity)[M-II(tfBDC)(H2O)(4)] (P (1) over bar, Z = 1; M-II = Zn (3), Co (4), Ni (5)) contains almost undistorted MI106 octahedra with the carboxylate groups of the tfBDC ligands in trans coordination so that a chain-like structural unit is formed. These chains are further connected by hydrogen bonds. Upon heating, these water molecules are released in two steps at 100 and 200 degrees C. (3)(infinity) [Mn-2(tfBDC)(2)(DMF)(2)(EtOH)] (P2(1), Z = 2, 7) is isostructural to the known Zn compound (6). Both compounds contain dimeric [(MO6)-O-II](2) units, which are connected by tfBDC(2-) ligands to form a 3D network. All compounds are unprecedented in the crystal chemistry of coordination polymers with nonfluorinated terephthalate (BDC2-) as bridging ligand. This is mainly because the planar conformation found for BDC2- is energetically less favorable for perfluorinated tfBDC(2-).