Three Wells-Dawson polyoxotungstates-based hybrid compounds of general formula [M(CHNO)][{M(CHNO)}(μ-PWO)]· nCHNO· n'HO [with M = Mn (1), Fe (2), Co (3) ; n = 2, 2, 3 and n' = 0, 0, 1, respectively] were synthesized at room temperature by a facile method and characterized by IR and H andP NMR spectroscopy studies, thermogravimetric analysis-differential scanning calorimetry thermal analyses, UV-vis, X-ray diffraction (XRD) powder and single-crystal XRD analyses, and cyclic voltammetry studies. From the X-ray study, it was established that the metal (M = Mn, Fe, Co) is located on an inversion center, being octahedrally coordinated to six dimethylformamide (DMF) molecules to form the complex cation [M(dmf)]. Also, in the dinuclear complex anion [{M(dmf)}(μ-PWO)], the M atoms are coordinated to five DMF molecules through the oxygen atoms, while the sixth coordination site is occupied by a terminal oxygen atom of the Wells-Dawson anion [PWO] that plays the role of a bridging ligand. The crystal components are connected through numerous weak C-H···O hydrogen bonds to construct a three-dimensional network. The UV-vis shows the two characteristic absorption bands for the three compounds at 266-268 and 297 nm. These two strong bands are attributed to the charge-transfer absorption band of Ot-W and Ob/c-W, respectively. Cyclic voltammetry study of compounds (1), (2), and (3) reveals at least two reduction reversible peaks ascribed to a Wells-Dawson cluster.

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In the title polyoxidometalate, the Wells–Dawson-type [P2W18O62]6− polyanion bridges two MnII octa­hedral complexes through terminal O atoms from the belts. The crystal components are connected through numerous weak C—H⋯O hydrogen bonds to construct a three-dimensional framework.

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