Two novel anion-directed Cu(II) double betaine coordination polymers with different open frameworks: Inorganic chains [Cu 3(μ 3–OH) 2(μ 2–H 2O) 2] n as secondary building units with unusual chair-like [Cu 3O 4] cores

Abstract

The reaction of double betaine ligand L 1 (L 1 = 1,3-bis(pyridinio-4-carboxylato)-propane) with Cu(ClO 4) 2 and Cu(NO 3) 2, respectively, afforded two novel anion-directed coordination polymers with different open frameworks. The structure of [Cu 3(L 1) 2(OH) 2(H 2O) 2](ClO 4) 4·2H 2O 1 is a unique 3-D open-framework with large S-shape channels, while [Cu 3(L 1) 2(OH) 2(H 2O) 2](NO 3) 4·2H 2O 2 has a 2-D tubular structure. There exist inorganic copper-oxo chains [Cu 3(μ 3–OH) 2(μ 2–H 2O) 2] n in both 1 and 2 as secondary building units, in which the [Cu 3O 4] cores exhibit a rarely observed chair-like configuration. The anion template of ClO 4 - and NO 3 - , and labile coordination orientation of L 1 ligand prompt the formation of different polymeric networks in 1 and 2.