Copper(II) 5-methoxyisophthalate coordination polymers incorporating dipyridyl co-ligands: syntheses, crystal structures, and magnetic properties

Hydrothermal reactions of mixed ligands 5-methoxyisophthalate (CH3O-H(2)ip) and dipyridyl with Cu(OAc)(2)center dot 2H(2)O afford five new coordination polymers, including {[Cu(CH3O-ip)(bpa)]center dot H2O}(n) (1), [Cu-2(CH3O-ip)(2)(bpa)(0.5)(H2O)](n) (2), [Cu-2(CH3O-ip)(2)(bpp)(H2O)](n) (3), {[Cu-3(CH3O-ip)(3)(bpp)(2)(H2O)]center dot 3H(2)O} (n) (4) and [Cu-4(CH3O-ip)(3)(bpe)(OH)(2)](n) (5) (bpp = 1,3-di(4-pyridyl)propane, bpa = 1,2-bi(4-pyridyl) ethane, and bpe = 1,2-di(4-pyridyl)ethylene). Compound 1 consists of CH3O-ip anion-bridged 1D Cu-II chains that are linked by trans-bpa into a 2D layer. Compound 2 is a 2D (4,4) layer that is connected by CH3O-ip anions. The gauche bpa in 2 lies in the cavity and meets the coordination requirement of the paddle-wheel dimeric copper unit. Compound 3 is an extended 3D polythreading network consisting of 2D (4,4) motifs with dangling bpp lateral arms. Compound 4 exhibits a 3D (4,6)-connected self-penetrating (6(5).8)(6(14).8) network that is composed of binuclear and mononuclear metal nodes. Compound 5 exhibits a 3D network with the tetranuclear [Cu-4(mu(3)-OH)(2)](6+) cluster acting as nodes, which is constructed by the interconnection of 2D helical layers via bpe pillars. The results of magnetic determination show that the syn -anti carboxylato bridges in our cases induce a weak antiferromagnetic interaction in 1, and the syn-syn carboxylato bridge in 3 and 4 mediates a strong antiferromagnetic interaction.