Keggin Arsenomolybdate Based Hybrid Compound with Complementary Inorganic Double Helical Chains

A new Keggin arsenomolybdate based inorganic–organic hybrid compound containing complementary inorganic double helical chains, Ag₂(pyttz)₃(H₂O)]HAsMo₁₂O₄₀]·H₂O (1), was successfully synthesized and characterized. Single crystal X-ray analysis reveals that compound 1 exhibits 3D supramolecular framework with (4³)(4⁴·6²)(4⁷·6¹⁰·8⁴) topology, in which the complementary double helical chains constructed by the left- and right-handed helical chains are found. In the crystal engineering point of view, the rich coordination atoms and conjugated heterocyclic rigid plane of pyttz organic ligand and the multiple twisted V-shaped coordination modes of Keggin POMs facilitate the formation of the inorganic helical structure. In addition, the title compound exhibits good photocatalytic degradation of methylene blue dye, and is very stable and easily separated from the catalytic system for reuse as well.