Cobalt- and Nickel-Containing Germanotungstates Based on Open Wells–Dawson Structure: Synthesis and Characterization of Tetrameric Anion

Two transition-metal-substituted compounds K10H10{[Co­(H2O)2]2[Co­(H2O)3]2(Ge4W36O130)}·32H2O (1Co) and K10H10{[Ni­(H2O)2]2[Ni­(H2O)3]2(Ge4W36O130)}·32H2O (2Ni), have been successfully synthesized, both of which consist of the S-shaped tetrameric structure {Ge4W36} constructed from trivacant Keggin-type germanotungstate precursor K8Na2[A-α-GeW9O34]·25H2O. These compounds were characterized by single crystal X-ray diffraction crystallography, X-ray powder diffraction (XRD), Raman spectra, thermogravimetric analysis (TGA), electrochemistry, and IR spectra. In addition, the UV spectra and the electrospray-ionization mass spectra (ESI-MS) were employed to investigated the stable pH value range of 1Co and 2Ni in aqueous solution.