A zinc(II) coordination polymer, [Zn4(o-bda)4(p-pbim)4]n, with strong blue fluorescence

A zinc(II) coordination polymer, [Zn4(o-bda)4(p-pbim)4]n (1) (p-pbim = 4-pyridylbenzimidazole, o-bda2- = o-phenylenediacetic acid dianion), has been synthesized by hydrothermal method and characterized by elemental analysis, IR, TG, photoluminescence and X-ray single crystal diffraction. Complex 1 crystallizes in a monoclinic system and space group P21/n, with a = 14.231(3) , b = 16.257(4) , c = 16.794(4) , = 100.262(1), and Z = 8; R1 for 6475 observed reflections [I 2(I)] was 0.0420. Complex 1 shows a bi-chain structure fabricated by the tetranuclear zinc unit. Two zinc(II) ions are five coordinate with distorted trigonal-bipyramid geometry; the other two zinc(II) ions are four coordinate with distorted tetrahedral geometry. Complex 1 builds the 1-D bi-chain structure with two different subrings A and B, which are 32-member and 14-member rings, respectively. There exists a 2-D supramolecular network linked by hydrogen-bonding interactions (2.695 and 2.807 ). A 3-D supramolecular network is further constructed by non-covalent interactions between the 1-D bi-chain structure. The TG/DTG shows that the chain skeleton is thermally stable to 356C. Blue fluorescent emission of the complex was determined at 404 nm in the solid state with short decay lifetime of 1.67 ns.