Syntheses, Structures, and Fluorescent Properties of Three ds-Block Metal Complexes with Pyrazine-2,3,5,6-tetracarboxylic Acid and 4,4 '-Bipyridine

Three coordination polymers {[Cd(pztc)(H2O)(2)]center dot(H(2)bpy)center dot 3(H2O)}(n). (1), {[Zn-3(pztc)(2)(Hbpy)(2)(bpy)(H2O)(4)]center dot 7H(2)O}(n) (2), and [Cu-6(pztc)(4)(Hbpy)(4)(bpy)(2)(H2O)(8)] center dot 17H(2)O (3) (bpy =4,4'-bipyridine, H(4)pztc=pyrazine-2,3,5,6-tetracarboxylic acid) have been synthesized and characterized by infrared spectra, elemental analysis, thermal analysis, fluorescence and single-crystal X-ray diffraction. The hydrogen bonding interactions in complexes 1 and 3 are abundant. Complex 2 displays a 3D network and exists an interesting goldfish-like (H2O)(10) cluster. Complex 3 shows 1D herringbone chain structures, which can be linked by hydrogen bonds to form a 3D supramolecular structure. In addition, on excitation of 320 nm, complexes 1 and 2 emit fluorescence with emission maximum at 496 nm and 494 nm respectively. CCDC: 888444, 1; 888445, 2; 888446, 3.