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

摘要

Three Cu(II) coordination polymers [Cu(taa)2]_n (1), [Cu(taa)2 · (H2O)4 · Na_(0.5) · (ClO4)_(0.5)]_n (2) and [Cu(taa)2 · (H2O)4 · Na_(0.5) · (BF4)_(0.5)]n (3) have been synthesized by the reaction of 1H-1,2,4-triazol-1-acetic acid (Htaa) with different Cu(II) salts. Polymer 1 features a 2-D grid-like network structure constructed by crossed zigzag chains. In both of polymers 2 and 3, there exist rare four-fold 1-D helical chains, which are induced by ClO_4~- or BF_4~- anions. Besides, trapped sodium chains are found to be nested in the channels formed by the intertwist of the helical chains of 2 and 3.