Room temperature synthesis and structural characterization of (NH 4 ) 15 Co 0.5 (NH 3 ) 3 [Co(NH 3 ) 4 NaSb 9 W 21 O 86 ]·15H 2 O—a novel chain-like inorganic cryptate

Abstract A novel one-dimensional infinite chain-like cryptate (NH 4 ) 15 Co 0.5 (NH 3 ) 3 [Co(NH 3 ) 4 NaSb 9 W 21 O 86 ]·15H 2 O ( I ) was synthesized at room temperature and characterized by elemental analyses, IR spectrum, UV spectrum, X-ray powder diffraction and X-ray crystal diffraction. It crystallized in the monoclinic system with space group P 2 1 / n , a =18.643(4), b =30.970(6), c=21.677(4) A , β =91.58(3)°, V=12 510(4) A 3 , Z =4 and D c =3.772 g cm −3 . It was constructed with building blocks, NaSb 9 W 21 O 86 18− , that were connected by bridging [Co(NH 3 ) 4 ] 2+ . NaSb 9 W 21 O 86 18− , which provides two terminal oxygen atoms as a didentate coordinates to [Co(NH 3 ) 4 ] 2+ forming an extended structure along the [001] plane. This is the first example of a chain structure in which a cryptate anion acts as a ligand to coordinate to the Co(II) ion. The magnetic susceptibility, measured in a temperature range of 75–300 K, shows a weak antiferromagnetic character of this compound.