Transformation from a Low-Dimensional Framework to a High-Dimensional Architecture Based on Different Metal Ions:  Syntheses, Structures, and Photoluminescences

Five novel metal pamidronates (3-ammonium-1-hydroxypropylidene-1,1-bisphosphonate, APD) formulated as Ni₂(C₃NH₁₀P₂O₇)₄·4H₂O (1), M(C₃NH₉P₂O₇)·H₂O (M = Co (2), Mn (3), Zn (4)) and Cu₃(C₃NH₈P₂O₇)₂·2H₂O (5) have been hydrothermally synthesized under similar conditions. Compound 1 is a molecular binuclear nickel cluster. Compounds 2 and 3 exhibit similar one-dimensional ladderlike structures. Compound 4 possesses a novel two-dimensional gridlike framework. Compound 5 shows an unusual three-dimensional architecture, in which two-dimensional layers with a parquet motif are pillared by {CuO₄} planar squares. Different dinuclear secondary building units (SBUs) are observed in compounds 1−5, depending on the different coordination modes of APD. They also exhibit different photoluminescence properties.