Syntheses, structures, sorption and magnetic properties of copper(II) frameworks with varied topologies

• Copper(II) frameworks with 5-[2-(pyridin-4-yl)vinyl]isophthalate.
• Selective sorption behavior of CO2 over N2.
• Magnetic property and DFT calculation.

A series of copper(II) complexes have been synthesized by reactions of ligand 5-[2-(pyridin-4-yl)vinyl]isophthalic acid (H2L) with Cu(NO3)2·3H2O via the alternation of reaction temperature and solvent system. The complexes were characterized by IR, single crystal and powder X-ray diffractions, and thermogravimetric analysis. {[Cu(HL)2]·2H2O}n (1) has a 1D hinged chain structure, while [CuL]n (2) is a (3,6)-connected 2D network with kgd topology. {[CuL]·0.5H2O}n (3) and [Cu2(L)2(H2O)]n (4) are (3,6)-connected 3D ScD0.33 net and flu-3,6-C2/c net, respectively. Interestingly, the E-form of free ligand is converted into Z-form during the formation of the complexes. The dehydrated complex 3 exhibits different sorption behavior for N2 and CO2. The magnetic properties of 1–4 were also investigated, and both experimental results and DFT calculations indicate that the more carboxylate groups bridging metal ions the stronger magnetic coupling observed in this system.

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