Zinc and cobalt complexes with (2-carboxyphenoxy) acetic acid ligand: syntheses, structures, fluorescent and magnetic properties

Four binary compounds, [Zn(cpa)(H2O)(3)] (1), [Co(cpa)(H2O)(3)] (2), [Zn(cpa)(H2O)](n), (3) and [Co(cpa)(H2O)](n) (4) (H(2)cpa=(2-carboxyphenoxy)acetic acid), have been synthesized and structurally characterized. In mononuclear 1 or 2, the metal ion (Zn-II for 1 and Co-II for 2) is surrounded by three water molecules and one tridentate chelate cpa(2-) in a distorted octahedral geometry, while in 3 or 4, the central metal ion (Zn-II for 3 and Co-II for 4) is located in a deformed square-pyramid formed by one water and two cpa(2-). Each cpa(2-) is chelate bridging (2) coordination and forms a 1-D zigzag chain structure 2 or 3. The different synthesis conditions for 1-4 have been carefully discussed. The solid-state fluorescence measurements for 1 and 3 together with magnetic properties for 4 also have been investigated.