Solvothermal syntheses, structures and fluorescent properties of six ZnII/CdII coordination polymers constructed from N-donor ligands and multidentate organic acid

Six new coordination polymers(CPs) {[Cd(L-1)(CHDA)]center dot H2O}(n) (1), [Zn-3(L-1)(2)(1,2,4-BTC)(2)(H2O)(4)](n) (2), [Zn(L-2) (D-CAM)(H2O)](n) ( 3 ), [Zn-3(L-2)(1,2,4-BTC)(2)(H2O)(4)](n )(4), [Cd(L-2)(1,3,5-HBTC)](n) (5) and {[Zn(L-2)(4,4'-BOA)]center dot H2O}(n) (6) (L-1 = 3,6-bis(imidazol-1-yl)pyridazine, L-2 = 3,6-bis(benzimidazol-1-yl)pyridazine, 1,4-H 2 CHDA = (1 S,4 S)-cyclohexane-1,4-dicarboxylic acid, 1,2,4-H3BTC = benzene-1,2,4-tricarboxylic acid, D-CAM = (1 R,3 S)-1,2,2-trimethylcyclopentane-1,3-dicarboxylic acid, 1,3,5-H3BTC = benzene-1,3,5-tricarboxylic acid, 4,4'-H(2)OBA = 4,4'-oxydibenzoic acid) were achieved by reactions of the corresponding metal salt with mixed organic ligands. Their structures were determined by single-crystal X-ray diffraction, IR spectra, elemental analysis, powder X-ray diffraction and thermogravimetric analysis. They exhibit varied structures, complexes 4 and 5 are porous three-dimensional (3D) frameworks, while 2 and 3 are 3D supermolecule structure formed by hydrogen-bonding interactions, and 1 is a two-dimensional (2D) network and 6 is an infinite one-dimensional (1D) chain. In addition, the fluorescent emission, fluorescence lifetimes of L-1, L-2 and 1-6 have been investigated and discussed.