Syntheses, Crystal Structures and Thermal Behavior of Five New Complexes Containing 2, 4, 6-Trifluorobenzoate as Ligand

Five new complexes containing 2, 4, 6-trifluorobenzoateas ligand have been synthesized and structurally characterized, namely Li(C6F3H2COO)(H2O) (P21, Z = 2, 1),Cs(C6F3H2COO)(C6F3H2COOH) (P21/c, Z = 4, 2),Cu(C6F3H2COO)2(H2O)2 (P, Z = 1, 3), Cu(C6F3H2COO)2(MeOH) (P21/c. Z = 4, 4) and Ag(C6F3H2COO)(H2O) (C2/c, Z = 8, 5). 1–3 and 5 are coordination polymers forming strands (1, 3, 5) or corrugated layers (2). In 1 and 2 the benzoate ligand acts as a bridging ligand, whereas in 3 and 5 the benzoate ligand is not bridging and the molecular units are interconnected by bridging water molecules. In 4 and 5, dimeric Cu2 and Ag2 units, respectively, are formed with short M···M contacts. The dimeric units in 4 resemble the well-known paddlewheel structural motif. In 5 these dimeric units are further connected by bridging water molecules, whereas in 4 only very weak F···H interactions connect the dimeric units. DTA/TG experiments on 1, 3 and 4 reveal that in a first step solvent molecules (H2O, MeOH) are unquestionably released. In 1–5 the torsion angles of the carboxylate group with respect to the aromatic ring deviate significantly from zero. These results are in very good agreement with the results of quantum chemical calculations of free 2, 4, 6-trifluorobenzoic acid and its dimer at the DFT and RI-MP2 level of theory.