1D zigzag chain and 0D monomer Cd(II)/Zn(II) compounds based on flexible phenylenediacetic ligand: Synthesis, crystal structures and fluorescent properties

Three novel Cd(II)/Zn(II) compounds, [Cd-2(Poda)(2)(phen)(3)(H2O)](n)center dot nEtOH center dot 3nH(2)O(1), [Zn(poda)(2)(bpy) (H2O)(n)(2) and [Zn(Hpoda)(2)(bpy)](3) (H(2)poda = 1,2-phenylenediacetic acid, phen = 1,10-phenanthroline, bpy = 2,2'-bipyridyl), have been synthesized and characterized by IR, TG, fluorescent spectrum and single-crystal X-ray diffraction techniques. In 1, poda (2-) anions link the adjacent Cd(II) centers to generate a 1D zigzag chain. Furthermore, an unprecedented four-footed 8-shaped mixed water-ethanol (H2O)(6)(C2H5OH)(2) cluster connects four double chains based on 1D zigzag chain into 3D supramolecular architecture. By bis(chelate-monodentate) fashion of poda(2-) ligand, compound 2 exhibits 1D zigzag chains, which forming a dense zipper-like 2D structure via strong pi-pi stacking interactions. Differed from 1 and 2, compound 3 has a mononuclear motif, and displays a 3D 6-connected alpha-Po net hydrogen-bonded topology. The structure-related solid-state fluorescence spectra of compounds 1 and 2 have been determined. (C) 2008 Elsevier B.V. All rights reserved.