Syntheses and Crystal Structures of Two New Cadmium(II) and Nickel(II) Complexes with 1,4-Phenylenediacetate and 2,2′-Bipyridyl-Like Ligands

Abstract

Two new complexes, namely [Cd(PDA)0.5(2,2′-bpy)Cl](H2PDA) (1) and [Ni(PDA)(phen)(H2O)]2 (2) (H2PDA = 1,4-phenylenediacetic acid, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline), have been synthesized and characterized by elemental analysis, IR spectra and X-ray crystal diffraction. Single-crystal X-ray diffraction analysis shows that complex 1 crystallizes in the triclinic space group P-1 with unit cell dimensions a = 8.760 (4) A, b = 11.190 (5) A, c = 13.917 (7) A, α = 110.383 (5)°, β = 101.736 (5)°, γ = 100.612 (5)°, V = 1202.8 (10) A3, Z = 2, R 1 = 0.0314 and wR 2 = 0.0898. Complex 2 crystallizes in the monoclinic space group P2(1)/n with unit cell dimensions a = 9.911 (3) A, b = 17.924 (6) A, c = 10.638 (4) A, β = 94.998 (5)°, V = 1882.7 (11) A3, Z = 2, R 1 = 0.0397 and wR 2 = 0.1150. In complex 1, Cd(II) ions are alternately bridged by PDA ligands and chloride ions into 1D chains and the PDA ligands display trans-configuration. Complex 2 is a dimer and two Ni(II) ions are linked by two PDA ligands with cis-configuration, resulting in a cyclic structure. In spite of these differences, both in complexes 1 and 2 there are π–π stacking interactions and hydrogen bonding to make them 3D supramolecular frameworks. Two new complexes [Cd(PDA)0.5(2,2′-bpy)Cl](H2PDA) and [Ni(PDA)(phen)(H2O)]2 (H2PDA = 1,4-phenylenediacetic acid, phen = 1,10-phenanthroline, 2,2′-bpy = 2,2′-bipyridine) were obtained and their structures were determined by single crystal X-ray diffraction. In complex [Cd(PDA)0.5(2,2′-bpy)Cl](H2PDA), Cd(II) ions are alternately bridged by PDA ligands and chloride ions into 1D chains and the PDA ligands display trans-configuration. The complex [Ni(PDA)(phen)(H2O)]2 is the first nickel(II) complex constructed by H2PDA. And two Ni(II) ions in one unit are linked by two PDA ligands with cis-configuration, resulting in a cyclic structure.