Synthesis and crystal structure of trans-diaqua(1,4,8,11-tetraazaundecane)copper(II) isophthalate monohydrate

Abstract

In the title hydrated molecular salt, [Cu(C7H20N4)(H2O)(2)](C8H4O4)center dot H2O, the metal ion is coordinated by the two primary and two secondary N atoms of the amine ligand and the mutually trans O atoms of the water molecules in a tetragonally distorted octahedral geometry. The average equatorial Cu-N bond lengths (2.013 and 2.026 angstrom for Cu-N-prim and Cu-N-sec, respectively) are substantially shorter than the average axial Cu-O bond length (2.518 angstrom). The tetraamine ligand adopts its energetically favored conformation with its five- and six-membered chelate rings in gauche and chair conformations, respectively. In the crystal, the N-H donor groups of the tetraamine, the acceptor carboxylate groups of the isophthalate dianion and both the coordinated water molecules and the water molecule of crystallization are involved in numerous N-H center dot center dot center dot O and O-H center dot center dot center dot O hydrogen bonds, resulting in the formation of electroneutral layers oriented parallel to the ac plane.