New Zn(II) coordination polymers with 1,3-bis(4-pyridyl)-propane: syntheses, crystal structures and properties

The ambient reactions of Zn(NO(3))(2)center dot 6H(2)O, 1,3-bis(4-pyridyl)-propane (bpp) and NaOH with benzoic acid, phenylacetic acid, phthalic acid, acetylenedicarboxylic acid afforded {Zn(bpp)(C(6)H(5)COO)(2)}center dot 2H(2)O 1, Zn(bpp)(C(6)H(5)CH(2)COO)(2) 2, {Zn(2)(bpp)(2)[C(6)H(4)(COO)(2)](2)}center dot 2H(2)O 3 and Zn(bpp)(C(4)O(4)) 4. Except 2, which crystallizes in a centrosymmetric space group P2(1)/n (no. 14), compounds 1, 3 and 4 crystallized in the acentric space groups Aba2 (no. 41), P2(1) (no. 4) and C222(1) (no. 20), respectively. Compounds 1 and 2 feature 1D zigzag chains 1 infinity {[Zn(C(6)H(5)COO(2)](bpp)(2/2)} and 1 infinity {[Zn(C(6)H(5)CH(2)COO(2)](bpp)(2/2)}, respectively, generated from [Zn(C(6)H(5)COO)(2)] and [Zn(C(6)H(5)CH(2)COO)(2)] moieties bridged by bpp ligands. In 3, the phthalato bridged helical chains 1 infinity {Zn[C(6)H(4)(COO)(2)](2/2)} are interlinked by TT- and TG-bpp ligands to form 3D MOF 3 infinity {Zn[C(6)H(4)(COO)(2)](2/2)(TT-bpp)(2/2)(TG-bpp)(2/2)} with a (6(5)center dot 8) CdS topology. The acetylenedicarboxylato bridged helical chains 1 infinity {Zn[C(2)(COO)(2)](2/2)} in 4 are interconnected by the bpp ligands to generate 3D MOF 3 infinity {Zn[C(2)(COO)(2)](2/2)(TT-bpp)(2/2)} with a (6(6)) diamond topology, and the formed crystal structure displays a four-fold interpenetration of the 3D MOF. Complexes 1, 3 and 4 exhibit significant ferroelectric behaviour (for 1 remnant polarization 2Pr = 3.97 x 10(-4) mu C cm(-2), coercive field 2Ec =0.47 kV cm(-1), saturation of the spontaneous polarization Ps 2.63 x 10(-3) mu C cm(-2); for 3 2Pr = 1.30 x 10(-3) mu C cm(-2), 2Ec = 1.02 kV cm(-1), Ps = 5.42 x 10(-3) mu C cm(-2); for 4 2Pr - 4.97 x 10(-4) mu C cm(-2), 2Ec -0.46 kV cm(-1), Ps - 2.08 x 10(-3) mu C cm(-2)). Additionally, 1 and 3 are verified to be SHG active. Furthermore, results about IR spectra, thermal analyses and fluorescence spectra were discussed.