Effect of the carboxyl groups on the assembly of copper pyridinedicarboxylate complexes

Three new copper(II) complexes [Cu(2,4-pydc)(phen)H2O][Cu(2,4-pydcH)2H2O] (1), [Cu2(2,3-pydc)2(phen)(H2O)2]·4H2O (2), [Cu(3,4-pydc)(phen)]·H2O (3) (2,4-pydcH2 = 2,4-pyridinedicarboxylic acid, 2,3-pydcH2 = 2,3-pyridinedicarboxylic acid, 3,4-pydcH2 = 3,4-pyridinedicarboxylic acid, phen = 1,10-phenanthroline) have been hydrothermally synthesized and characterized by the elemental analyses, IR spectra and the single crystal X-ray diffraction. In all three compounds, the coordination sphere of the Cu metal is square–pyramidal geometry, but the three complexes bear different structures. The complex 1 is a 0D structure composed of two separate Cu units, and the complex 2 has a 1D Zig–Zag chain containing 3D hydrogen bonding net, while the complex 3 exhibits a 2D brickwall-like structure.