Two novel anion-directed Cu(II) double betaine coordination polymers with different open frameworks: Inorganic chains [Cu3(μ3–OH)2(μ2–H2O)2]n as secondary building units with unusual chair-like [Cu3O4] cores

The reaction of double betaine ligand L1 (L1 = 1,3-bis(pyridinio-4-carboxylato)-propane) with Cu(ClO4)2 and Cu(NO3)2, respectively, afforded two novel anion-directed coordination polymers with different open frameworks. The structure of [Cu3(L1)2(OH)2(H2O)2](ClO4)4·2H2O 1 is a unique 3-D open-framework with large S-shape channels, while [Cu3(L1)2(OH)2(H2O)2](NO3)4·2H2O 2 has a 2-D tubular structure. There exist inorganic copper-oxo chains [Cu3(μ3–OH)2(μ2–H2O)2]n in both 1 and 2 as secondary building units, in which the [Cu3O4] cores exhibit a rarely observed chair-like configuration. The anion template of image and image, and labile coordination orientation of L1 ligand prompt the formation of different polymeric networks in 1 and 2.