Three-Dimensional Structure of Barium-Cupric Nitrilotriacetate and One-Dimensional Structure of Cobalt-Cupric Nitrilotriacetate: Template Effect of Cations on the Formation of Coordination Polymers

Abstract

Three mixed-metal nitrilotriacetates [Ba(H2O)3Co(nta)Cl]n (1), [Ba(H2O)3Ni(nta)Cl]n (2), and [Ba(H2O)3Cu(nta)Cl]n (3) (H3nta = nitrilotriacetic acid) were prepared by the reaction of M2+ ions (M = Co, Ni, and Cu), K3nta, and Ba2+ ions in water. The reaction of complexes 1 and 2 with CuSO4·5H2O afforded [Co(H2O)6]n[Cu2(nta)2]n·2nH2O (4) and [Ni(H2O)6]n[Cu2(nta)2]n·2nH2O (5), respectively. The reaction mechanism was elucidated. The crystal structure analyses indicate that the Ba2+ ions formed one-dimensional (1D) zigzag chains in complex 3, and the chains were connected by Cu(nta)- anions to form a three-dimensional network. On the other hand, in complexes 4 and 5, the Cu(nta)- anions formed 1D zigzag chains, and the [Co(H2O)6]2+ (or [Ni(H2O)6]2+) cations existed as isolated units. © 2014 The Author(s).