Structural diversity of Mn(II) and Cu(II) complexes based on 2-carboxy-phenoxyacetate linker: Syntheses, conformation comparison and magnetic properties

Four new binary complexes with 2-carboxyphenoxyacetic acid ligand (2-H(2)cpa), namely [Mn(2-cpa)(H2O)(3)] (ODMn), [Cu(2-cpa)(H2O)(3)] (0D-Cu), [Mn(2-cpa)(H2O)](n) (1D-Mn) and [Cu(2-cpa)(H2O)](n) (2D-Cu), have been successfully prepared and systematically characterized. Structure analyses indicated that 0D-Mn and 0D-Cu are isomorphous mononuclear species in which the 2-carboxyphenoxyacetate (2-cpa) is a tridentate chelate anionic ligand. 1D-Mn is a 1D zigzag chain structure formed by the tetradentate bridging chelate-mu 2 coordination pattern of 2-cpa connecting adjacent Mn-II ions. While 2D-Cu is a 2D corrugated (4,4)-connected layer and 2-cpa adopts pentadentate double bridging chelate-mu(3) coordination mode in it. The different synthetic conditions, crystal structures and conformation of 2-cpa in the above compounds have been carefully analyzed and the results revealed that the synthetic conditions and flexible conformation of 2-cpa may be responsible for the structural diversity of binary 2-cpa metal complex system. In addition, the magnetic measurements showed that between the neighbouring metal ions there are weak ferromagnetic exchange in 0D-Mn and 0D-Cu, but antiferromagnetic coupling in 1D-Mn and 2D-Cu, respectively.

Automated summary

Four new binary complexes with 2-carboxyphenoxyacetic acid ligand have been successfully synthesized and characterized. The structures of these complexes show diversity due to different synthetic conditions and flexible conformation of the ligand. Magnetic measurements indicate weak ferromagnetic exchange in 0D-Mn and 0D-Cu, but antiferromagnetic coupling in 1D-Mn and 2D-Cu.