Synthesis and characterization of new two-dimensional molybdenum(V) phosphates: (Hen)6[M2(H2O)Mo12O24(OH)6(H2PO4)3(HPO4)4(PO4)]·4H2O (M = K, Na)

Two new reduced molybdenum(V) phosphates, (Hen)6[K2(H2O)Mo12O24(OH)6(H2PO4)3(HPO4)4(PO4)]·4H2O and (Hen)6[Na2(H2O)Mo12O24(OH)6(H2PO4)3(HPO4)4(PO4)]·4H2O (en = ethylenediamine) have been prepared under hydrothermal conditions and characterized by elemental analyses, IR and single-crystal X-ray diffraction. It was revealed that the sandwich-shaped units [M(Mo6P4)2] are linked by additional octahedrally-coordinated K or Na atoms into two-dimensional layers. The ethylenediamine cations and the lattice water molecules are nestled in the spaces between layers, and are interacted with the inorganic networks through hydrogen bonds into a three-dimensional supramolecular framework. It was indicated that the compounds exhibit photocatalytic activity in the degradation of rhodamine B.