A hydrostable and twofold interpenetrating three-dimensional zinc-organic framework with rob topology based on 4,4'-oxydibenzoate and 3,3'-dimethyl-4,4'-bipyridine ligands

Assembly of ZnII and CdII coordination polymers with different dimensionalities based on the semi-flexible 3-(1H-benzimidazol-2-yl)propanoic acid ligand

Two new coordination polymers, namely, poly[[μ3-3-(1H-benzimidazol-2-yl)propionato]zinc(II)], [Zn(C10H8N2O2)] n , (1), and poly[bis-[μ2-3-(1H-benzimid-azol-2-yl)propionato]cadmium(II)], [Cd(C10H8N2O2)2] n , (2) have been synthesized from 3-(1H-benzoimidazol-2-yl)propanoic acid ligands through a mixed-ligand synthetic strategy under a solvothermal environment, and studied by single-crystal X-ray diffraction. Complex 1 crystallizes in the ortho-rhom-bic space group Pbca and features a two-dimensional structure formed by a binuclear Zn2O4 core. Complex 2, however, crystallizes in the monoclinic space group P21/c and forms a one-dimensional chain structure. The ZnII and CdII ions have different coordination numbers and the 3-(1H-benzoimidazol-2-yl)propano-ate ligands display different coordination modes. The structures reported here show the importance of the selection of metal ions and suitable ligands.

New fluorescent compounds based on zinc thiocyanate: influence of structure on spectral properties

New coordination compounds based on zinc thiocyanate, namely (acetone thiosemicarbazone-κ²N¹,S)bis(isothiocyanato-κN)zinc(II) monohydrate, [Zn(NCS)₂(C₄H₉N₃S)]·H₂O, (I), and diaquatetrakis(urea-κO)zinc(II) tetrakis(isothiocyanato-κN)zinc(II), [Zn(CH₄N₂O)₄(H₂O)₂][Zn(NCS)₄], (II), were synthesized and studied by UV-Vis, fluorescence and IR spectroscopy. Coordination salt (II) forms a rare system composed of two different coordination units of the same metal and it is the first example of a compound with two completely different zinc coordination units, of which one contains a tetrakis(urea)zinc unit. Both (I) and (II) possess fluorescence properties and produce blue and green emissions, respectively, upon irradiation with violet light. The spectral properties were correlated with the observed molecular and supramolecular structures. The acetone thiosemicarbazone ligand of (I) exhibits (upon coordination) red shifts of bands corresponding to N=C and C=S stretching vibration frequencies, which is not typical for chelating molecules.