Vacant polyoxometalates

Predicted vacant polyoxometalates can be easily obtained by controlled hydrolyses, and are good reactive nucleophiles that can form a remarkable set of precursors for the design of large soluble molecules. 

Transition metals substituted polyoxometalates are obtained starting from vacant or lacunary POMs. The latter are derived from the saturated parent POM, through formal loss of one or more MOe octahedral units. Such complexes present several coordinatively unsaturated oxygen atoms, which surround the defect and form a polydentate site, able to coordinate a multitude of transition metals, M . Fundamental modes of coordination of the transition metals are in pocket and out of pocket , the latter including sandwich-like structures and metal oxide cluster stabilization, depending both on the dimensions of M and on the stoichiometic ratio between M and the vacant units. " ... 

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