3D-transition metal mono-substituted Keggin polyoxotungstate with an antenna molecule: synthesis, structure and characterization

Three new organic-inorganic hybrid complexes based on 3d-transition metal monosubstituted Keggin polyoxometalates (POMs) with imidazole (Im) as pendant ligands, formulated as (HIm)(6)-[SiW(11)O(39)NiIm](0.8)[SiW11O39Ni(H2O)](0.2)center dot 7H(2)O (1), (Im)(4)Na-6[SiW(11)O(39)MnIm](0.69)[SiW11O39Mn(H2O)](0.31)center dot 7.5H(2)O (2) and (HIm)(6)[SiW(11)O(39)CoIm](0.63)[SiW11O39Co(H2O)](0.37)center dot 7H(2)O (3), have been synthesized and characterized by IR spectroscopy, UV-visible spectroscopy, elemental analysis, TG analysis, cyclic voltammetry, magnetic properties, EPR and single-crystal/powder X-ray diffraction. The structural analyses indicate that the 3d metal atoms are incorporated into the vacancy of the alpha-[SiW11O39](8-) (SiW11). Complexes 1-3 are the first examples of crystallographically characterized 3d-transition metal mono-substituted POMs with an antenna organic ligand synthesized under normal bench conditions.