Metal-Organic Framework Based on Pyridine-2,3-Dicarboxylate and a Flexible Bis-imidazole Ligand: Synthesis, Structure, and Photoluminescence

A novel metal-organic framework {[Zn(2,3-pydc)(bbi)]center dot 0.5CH(3)CN center dot 2H(2)O} (n) (2,3-pydc = pyridine-2,3-dicarboxylate, bbi = 1,1'-(1,4-butanediyl)bis(imidazole)) (1), was prepared under hydrothermal conditions and characterized by elemental analyses, IR and X-ray diffraction. Crystal data for 1 are monoclinic, space group C2/c, a = 19.685(2) , b = 14.332(1) , c = 16.930(2) , beta = 121.205(2)A degrees, U = 4085.3(6) (3), Z = 4. The results reveal that the Zn(II)-atom is five-coordinated with two O-atoms and three N-atoms forming a distorted trigonal bipyramidal geometry. The Zn(II) atoms are bridged by 2,3-pydc and bbi ligands, leading to a three-dimensional network. The Zn center dot center dot center dot Zn separations are 8.277 [through the 2,3-pydc bridge] and 12.638 [through the bbi bridge]. Additionally, 1 shows strong fluorescence in the solid state at room temperature.