Synthesis and structure of a three-dimensional organically templated zinc ethylenediphosphonate,[NH₃(CH₂)₂NH₃] [Zn₃{O₃P(CH₂)₂}₄]

Abstract

A hydrothermal reaction of a mixture of ZnO, HCl, ethylenediphosphonic acid, ethylenediamine, acetic acid in a water, THF mixture gave rise to a new three-dimensional zinc ethylenediphosphonate, [NH₃(CH₂)₂NH₃][Zn₃{O₃P(CH₂)₂}₄], I. The structure, determined by single crystal X-ray diffraction, (monoclinic, space group = C2/c, a = 16.9948(14), b = 6.7383(6), c = 16.8886(14)Å, β = 1113.568(1)°, V = 1772.7(3)ų, Z = 4, R₁ = 0.0227, wR₂ = 0.0601), consists of a network of strictly alternating ZnO₄ and PO₃C tetrahedral units linked through their vertices forming the three-dimensional structure. The amine molecules occupy the middle of the 8-membered channels and interact with the framework through the hydrogen bonds. Unlike other zinc diphosphonates, I appear to have close similarity to zinc phosphate structures reported in the literature. To our knowledge, this is the first three-dimensional zinc diphosphonate prepared in the presence of an organic amine molecule.