Two Interesting One-Dimensional Chainlike Architectures Formed by Substituted Keggin Polyoxoanions and Novel Cobalt–Ethylenediamine Complexes

Two novel supported heteropolytungstates, NaH3[CoIII(en)2(OH)SiW11CoIIO39]·9.25H2O 1 (en = ethylenediamine) and [Co(en)2]4[Co4(Hen)2Si2W18O68]·H2en·6H2O 2 have been synthesized and characterized by single-crystal X-ray diffraction, electrochemistry, IR, and thermogravimetry. Compound 1 exhibits an interesting one-dimensional chainlike architecture assembled by bridged sodium ions that support monosubstituted Keggin polyoxoanions. To our knowledge, it represents the first example of a supported structure that consists of monosubstituted Keggin polyoxoanions and a novel interbridged, dinuclear Co metal unit. Compound 2 is constructed from trivacant Keggin polyanions linked through a tetrameric cobalt unit, which coordinates with organonitrogen ligands. Moreover, the sandwich-type polyoxoanions were connected by two [Co(en)2] coordination complexes, respectively, and linked by Co2+ ions into a straight chain.