Three 3d-4f Tetranuclear Complexes Based on 2,3,5-Trichlorobenzoic Acid: Syntheses, Structures, and Magnetic Properties

The solvothermal reactions of 2,3,5-trichlorobenzoic acid (HL) 2,2'-bipyridine (bipy), CoCl2 center dot 6H(2)O, and Ln(2)O(3) afforded three novel 3d-4f tetranuclear complexes Co(2)Ln(2)(L)(10)(bipy)(2) (Ln = Dy 1, Ho 2, and Er 3), which have been characterized by single-crystal X-ray diffraction, infrared spectroscopy, and element analyses. Complexes 1-3 crystallize in the triclinic space group P (1) over bar, and the completely deprotonated L ligands possess mu(2): eta(2), eta(1) and mu(2): eta(1), eta(1) coordination modes to bridge adjacent metal ions, which further connect into 2D layers by hydrogen bonds. Magnetic studies indicate ferromagnetic interactions between adjacent metal ions in complexes 1 and 3.