Hydrothermal synthesis,characterization and photoluminescence property of a novel indium phosphate with 3D supramolecular structure

A one-dimensional chained indium phosphate In(H₂PO₄)(HPO₄)(C₁₀N₂H₈) (1) was synthesized under hydrothermal condition using 2,2′-bipyridine as a ligand and characterized by IR spectroscopy, ICP and elemental analyses, powder and single crystal X-ray diffraction analyses. Compound 1 crystallizes in the triclinic system, space group P-1. The connection of In-centered octahedra (InO₄N₂) and P-centered tetrahedra ({PO₃(OH)} and {PO₂(OH)₂}) constructs a new type of 1D chained structure with In/P ratio of 1/3. Interestingly, H₂PO₄ tetrahedron and 2,2′-bipyridine ligands "hanging" in the chain by bridging oxygen atoms and nitrogen atoms bond to the central In atoms. It is noted that the adjacent chains are stably packed together and the final structure exhibits interesting three-dimensional (3D) supramolecular array via π–π interactions of the 2,2′-bipyridine groups and hydrogen-bond interactions. Additionally, compound 1 shows strong photoluminescence property in the solid state at room temperature.