A series of bis(pyridyl)-bis(amide)-modulated metal-1,2-phenylenediacetate coordination polymers: construction and selective dye adsorption

Abstract

Five new coordination polymers (CPs), namely, [Cu(3-bpcb)(1,2-pda)]·2H₂O (1), [Cu(4-bpah)(1,2-pda)(H₂O)]·H₂O (2), [Ni₂(4-bpah)₂(1,2-pda)₂(μ₂-H₂O)] (3), [Cu₃(4-bpfp)(1,2-pda)₂(μ₃-OH)₂] (4), [Co(4-bpfp)_0.5(1,2-pda)(H₂O)] (5), were prepared by hydrothermal reactions of metal(II) chloride with 1,2-H₂pda (H₂pda = 1,2-phenylenediacetic acid) in the presence of different bis(pyridyl)-bis(amide) ligands (3-bpcb = N,N′-bis(3-pyridinecarboxamide)-1,4-benzene; 4-bpah = N,N′-bis(4-pyridinecarboxamide)-1,2-cyclohexane; and 4-bpfp = N,N′-bis(4-pyridylformyl)piperazine) and structurally characterized by single crystal X-ray diffraction, infrared spectroscopy (IR), elemental analysis, powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA). Complexes 1–3 show three different 2D layers with diverse (4²·6⁷·8)(4²·6), (4⁴·6²) and (4²·6)(4²·6⁷·8) topological structures, respectively. Complex 4 exhibits a 3D polymeric framework, which presents a novel (3,4,8)-connected topology with the Schläfli symbol (3·4·5)₂(3²·4²·5²·6¹⁴·7⁴·8³·9)(3²·6³·7). Complex 5 displays a 3D network with 3,4-connected (4²·6³·8)(4²·6) topology. The diverse arrangements of these complexes show the remarkable sensitivity of the metal(II)–H₂pda system to the different bis(pyridyl)-bis(amide) ligands. In addition, the electrochemical properties of complexes 3–5 and the dye adsorption properties of the title complexes are also discussed.