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

Abstract

Three Zn(II) complexes, [Zn2(bpp)2(FNA)2]·H2O (1), [Zn(bpp)(FNA)]·H2O (2), and Zn2(bpp)2(FNA)2 (3) (bpp = 1,3-bi(4-pyridyl)propane, H2FNA = 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 (65·8) CdS topology. Complex 3 features 1-D zigzag chains, which are interconnected by bpp ligands to give a 3-D framework with (6·74·8)(64·7·8) topology. Complexes 2 and 3 exhibit significant ferroelectric behavior (for 2 remnant polarization Pr = 0.050 μC cm−2, coercive field Ec = 1.13 kV cm−1, saturation of the spontaneous polarization Ps = 0.239 μC cm−2; for 3 Pr = 0.192 μC cm−2, Ec = 4.64 kV cm−1, Ps = 0.298 μC cm−2).