Anion-dependent assemblies of two unprecedented copper(II) polymers with four-fold screw axes and trapped sodium chains

Anion-dependent assemblies of two unprecedented copper(II) polymers with four-fold screw axes and trapped sodium chains Three Cu(II) coordination polymers [Cu(taa)2]n (1), [Cu(taa)2 · (H2O)4 · Na0.5 · (ClO4)0.5]n (2) and [Cu(taa)2 · (H2O)4 · Na0.5 · (BF4)0.5]n (3) have been synthesized by the reaction of 1H-1,2,4-triazol-1-acetic acid (Htaa) and a series of Cu(II) salts. polymer 1 consists of crossed zigzag chains. In both of polymers 2 and 3, there exist rare four-fold 1-D helical chains, which are induced by ClO4- or BF4- anions.