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, [Cd2(poda)2(phen)3(H2O)]n·nEtOH·3nH2O(1), [Zn(poda)2(bpy)(H2O)]n(2) and [Zn(Hpoda)2(bpy)](3) (H2poda = 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, poda2− 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 poda2− ligand, compound 2 exhibits 1D zigzag chains, which forming a dense zipper-like 2D structure via strong π-π stacking interactions. Differed from 1 and 2, compound 3 has a mononuclear motif, and displays a 3D 6-connected α-Po net hydrogen-bonded topology. The structure-related solid-state fluorescence spectra of compounds 1 and 2 have been determined.