An α-Keggin polyoxometalate completely constructed from the late transition metal Co(II) as poly atom.

We report a catalytic eight-cobalt-capped α-Keggin polyoxoazocobaltite with a highly symmetric structure completely constructed from the late transition-metal Co(II) as a poly atom, [Co(20)(OH)(24)(MMT)(12)(SO(4))](NO(3))(2)·6H(2)O (1) (MMT: 2-mercapto-5-methyl-1,3,4-thiadiazole). To the best of our knowledge, this is the first homometallic Co(II) magnetic cluster bearing Keggin structure. It can serve as a potential catalyst in the styrene polymerization.

A remarkable member of the polyoxometalates: the eight-nickel-capped alpha-keggin polyoxoazonickelate.

The eight-nickel-capped polyoxoazonickelate, [Ni(20)(OH)(24)(MMT)(12)(SO(4))](NO(3))(2).6H(2)O (1; MMT = 2-mercapto-5-methyl-1,3,4-thiadiazole), has been synthesized, which has an alpha-Keggin structure with eight nickel caps. In this structure, the polyatom is the late transition metal Ni(II); the central heteroatom is S, and the organic terminal ligand becomes the primary part of the Keggin structure. This is a Keplerate-type cluster, which shows a central Ni(II)(12) cuboctahedron formed by the 12 Ni(II) centers of the classical alpha-Keggin core and a Ni(II)(8) hexahedron formed by the eight nickel caps.