Two new cantilever-type polyoxometalates constructed from {Mo ₂ O ₄ } ²⁺ fragments and diphosphonates

Two new cantilever-type polyoxometalates Na(5)(NH(4)){V(IV)[(Mo(2)O(6))CH(3)C(O)(PO(3))(2)](2)}.13H(2)O (1) and (NH(4))(4){V(IV)[(Mo(2)O(6))NH(3)CH(2)CH(2)CH(2)C(O)(PO(3))(2)](2)}.6H(2)O (2) have been synthesized and characterized by IR spectroscopy, UV-visible spectroscopy, elemental analysis, TG analysis, XPS, (31)P NMR and single-crystal X-ray diffraction. The structure analysis reveals that the diphosphonate, hydroxyethylidene diphosphonic acid and alendronic acid as the scaffolds, have been grafted on the "S"-shaped polyoxoanions and respectively. The alkyl groups of the diphosphonates like arms hanged on the polyoxoanions form the cantilever-type polyoxometalates.