Synthesis, characterization and crystal structure of a dodeca-nuclear cobalt (II)cube-octahedron

Abstract

<p>The new cobalt (II) complex, [Co<sub>12 </sub>(cpip)<sub>12</sub>(H<sub>2</sub>O)<sub>12</sub>].18.56H<sub>2</sub>O where H<sub>2</sub>cpip = 2-(carboxy-phenyl) amino-propanoic acid, was isolated as pink-like prism crystals from the reaction of Co(NO<sub>3</sub>)<sub>2</sub>.6H<sub>2</sub>O and H<sub>2</sub>cpip in an ethanolic solution. The complex was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and X-ray single-crystal diffraction. The symmetric unit of the title complex contains twelve cobalt atoms arranged in a cube-octahedron. Each divalent cation of cobalt is iso-octahedrally coordinated to four oxygen atoms of two cpip2- ligands in the equatorial plane. The axial plane is occupied by an amino nitrogen atom of one of the cpip2- ligands and an oxygen atom of a water molecule. The lattice water molecule in the metallocycle cavity involved OH­­­O hydrogen bonding with the coordinated water molecules.</p>