A three-dimensional Cu–Na heteronuclear coordination polymer based on iminodiacetic acid

Abstract

A novel Cu–Na heteronuclear three-dimensional coordination polymer, poly[diaquadi-μ5-iminodiacetato-di-μ4-iminodiacetato-tricopper(II)disodium(I)], [Cu3Na2(C4H5NO4)4(H2O)2]n, has been prepared by hydrothermal synthesis. The asymmetric unit contains one and a half copper(II) cations, a sodium cation, two iminodiacetate (ida) ligands and a coordinated water ligand. One of the two independent CuIIcentres is in a general position and is five-coordinated in a distorted square-pyramidal geometry. A [Cu(ida)] unit is formedviaa bis-chelating ida ligand and the coordination sphere of the CuIIatom is completed by two O atoms of two different neighbouring [Cu(ida)2] units. These [Cu(ida)2] units are associated with the second CuIIcation, which is located on a crystallographic inversion centre and is coordinated in a distorted square-planar geometry by two chelating ida ligands. The carboxylate groups of the ida ligands act as bridges and connect the [Cu(ida)] and [Cu(ida)2] building blocks in a 2:1 ratio, forming two-dimensional arrays. These layers are interconnected into a three-dimensional structure by the sodium ions. Each NaIcation is coordinated by six O atoms from five ida ligands and a water molecule. When [Cu(ida)], the NaIcations and [Cu(ida)2] are viewed as 5-, 5- and 8-connected nodes, respectively, the three-dimensional network exhibits a (32.43.52.63)2(32.43.52.63)2(34.616.78) topology.