Three multifunctional three-dimensional metal-organic frameworks based on a flexible N, N′-bis(3-pyridinecarboxamide)-1,6-hexane and 3-nitrophthalate: Syntheses, structures and properties

Three multifunctional three-dimensional (3D) metal-organic frameworks (MOFs) based on the 3-nitrophthalic acid (3-H2NPH) and a flexible bis-pyridyl-bis-amide N, N'-bis(3-pyridinecarboxamide)-1,6-hexane (3-dpyh), namely, [Cu(3-dpyh)(3-NPH)(H2O)(2)] (1), [Ni(3-dpyh)(3-NPH)(H2O)(2)] (2), [Co(3-dpyh)(3-NPH)(H2O)(2)] (3), have been hydrothermally synthesized and structurally characterized. X-ray diffraction analyses reveal that the title complexes are isostructural 3D frameworks. In complexes 1-3, the 3-dpyh shows a mu 2-bridging mode to link the adjacent metal ions, forming [M(II)-3-dpyh](n) meso-helical chains (M = Cu/Ni/Co). Two carboxyl groups of the 3-NPH anion connect the adjacent metal ions with a mu(1)-eta(1): eta(0) mode to form [M(II)-3-NPH](n) meso-helical chains, which further connect with the [M(II)-3-dpyh](n) chains, constructing 3D frameworks with CdSO4-like topology. The fluorescent, electrochemical, and photocatalytic properties of complexes 1-3 have also been investigated. (C) 2013 Elsevier B. V. All rights reserved.