Template synthesis of {(MoV2O4)(O3PCH2PO3)}n clusters (n=3, 4, 10):: solid state and solution studies

The influence of three exogenous ligands (acetate, formate and carbonate) on the condensation process of the [Mo2O4](2+) dioxocation with the [O3PCH2PO3](4-) group has been investigated. Four cyclic or bicyclic compounds have been isolated and characterized by X-ray diffraction studies. Two closely related acetato and formato ovoidal duodecanuclear compounds, Na-24[Na-4(H2O)(6){(Mo2O4)(10)(O3PCH2PO3)(10)(CH3COO)(8)(H2O)(4)}] . 103H(2)O (1) and Na-28[Na-2{(Mo2O4)(10)(O3PCH2PO3)(10)(HCOO)(10)}] . 110H(2)O (2), respectively, have been obtained. Their structures can be described as two interconnected nonequivalent wheels, delimiting a large cavity. When the condensation is performed in similar conditions but replacing carboxylato groups by carbonato ligands, the ellipsoidal octanuclear Na-11[Na(H2O)(2){(Mo2O4)(4)(O3PCH2PO3)(4)(CO3)(2)}] . 70H(2)O (3) compound is isolated. P-31 NMR spectroscopic studies have shown that complexes 1 and 3 are stable in solution at room temperature. Nevertheless, on heating an aqueous solution of 3, the Na-8[(Mo2O4)(3)(O3PCH2PO3)(3)(MoO4)] . 18H(2)O (4) complex, free of carbonato groups, is obtained. 4 is a hexanuclear Mo-V wheel encapsulating a tetrahedral [(MoO4)-O-VI](2-) anion. Its rational synthesis using a controlled Mo-V/Mo-VI ratio is also presented.