Synthesis, X-Ray Structure, and Characterization of a Complex Containing the Hexakis(urea)cobalt(II) Cation and Lattice Urea Molecules

Abstract

The 12: 1 reaction of urea (U) with CoI2 in EtOH yielded the “clathrate-coordination” compound [CoU6]I2·4U (1). The complex crystallizes in the monoclinic space group P21/c. The lattice constants are a = 9.844(4), b = 7.268(3), c = 24.12(1) Å, and β=98.12(1)∘. The crystal structure determination demonstrates the existence of octahedral [CoU6]2+ cations, I- counterions, and two different types (two U1 and two U2) of hydrogen-bonded, lattice urea molecules. The [CoU6]2+ cations and the U1 lattice molecules form two-dimensional hydrogen-bonded layers which are parallel to the ab plane. The I- anions are placed above and below each layer, and are hydrogen bonded both to U1 molecules and [CoU6]2+ cations. Each U2 molecule is connected to a [CoU6]2+ cation through an N–H⋯O hydrogen bond resulting in a three-dimensional network. Room temperature magnetic susceptibility and spectroscopic (solid-state UV/Vis, IR, Raman) data of 1 are discussed in terms of the nature of bonding and the known structure.