Structural diversity for three Zn(II) coordination polymers from 4-nitrobenzene-1,2-dicarboxylate and bispyridyl ligand

Three Zn(II) complexes, [Zn-2(bpp)(2)(FNA)(2)]H2O (1), [Zn(bpp)(FNA)]H2O (2), and Zn-2(bpp)(2)(FNA)(2) (3) (bpp=1,3-bi(4-pyridyl)propane, H(2)FNA=4-nitrobenzene-1,2-dicarboxylic acid), were synthesized and characterized by single-crystal and powder X-ray diffraction methods, IR spectroscopy, TG analyses, elemental analyses, and fluorescent analysis. In 1, the Zn(II) ions are linked by FNA anions and bpp into 2-D layers. The Zn(II) ions in 2 are bridged by FNA anions into chiral chains, which are interlinked by bpp into 3-D metal-organic framework with (6(5)8) CdS topology. Complex 3 features 1-D zigzag chains, which are interconnected by bpp ligands to give a 3-D framework with (67(4)8)(6(4)78) topology. Complexes 2 and 3 exhibit significant ferroelectric behavior (for 2 remnant polarization Pr=0.050 Ccm(-2), coercive field Ec=1.13kVcm(-1), saturation of the spontaneous polarization Ps=0.239 C cm(-2); for 3Pr=0.192Ccm(-2), Ec=4.64kVcm(-1), Ps=0.298Ccm(-2)). [GRAPHICS]