Syntheses, crystal structures and luminescent properties of four Zn(II) coordination polymers with pyrazolone derivatives and 4,4′-bipyridine

Four new Zn(II) coordination polymers, {[Zn(L-1)(4,4'-bipy)]center dot 0.52CH(3)OH}(n) (1), {[Zn(L-2)(4,4'-bipy)]center dot CH3OH}(n) (2), {[Zn-3(L-3)(3)(4,4'-bipy)(0.5)]center dot 3CH(3)OH}(n) (3), {[Zn(L-4)(4,4'-bipy)]center dot 2CH(3)OH}(n) (4) (H2L1 = N-(1,3-diphenyl-4-propylene-5-pyrazolone) p-nitrobenzoylhydrazide, H2L2 = N-(1-phenyl-3-benzyl-4-propylene-5-pyrazolone) p-nitrobenzoylhydrazide, H2L3 = N-(1,3-diphenyl-4-propylene-5-pyrazolone) isoniazid, H2L4 = N-(1-phenyl-3-benzyl-4-propylene-5-pyrazolone) isoniazid, 4,4'-bipy = 4,4'-bipyridine) have been synthesized by the reactions of zinc acetate with the corresponding 4-acyl pyrazolone derivatives and 4,4'-bipyridine. The X-ray diffraction analyses revealed that complexes 1 and 2 exhibit 1D zigzag chain structures. The ligands (H2L1 and H2L2) serve as divalent tridentate chelating agents to coordinate with Zn(II) atoms. Complex 3 displays a complicated pillared-layer 3D framework and the ligands H2L3 adopt two different kinds of coordination modes. In the case of complex 4, the octahedral Zn(II) atoms are connected by the tetradentate ligands to form a 1D chain, then the 4,4'-bipyridine molecules further connect the 1D chains along the axial direction to generate a 2D network structure. The effect of the coordination groups and substituents at the 3-position of the ligands on the structure of the complexes have been discussed. Additionally, the luminescent properties of the complexes have been investigated in the solid state.