Supramolecular 2D and 3D frameworks based on 1-amino-2-phenylethane-1,1-diphosphonic acid

The 1-amino-2-phenylethane-1,1-diphosphonic acid (APhEDPH4) is easily assembled to form two-dimensional (2D) supramolecular layer. It crystallizes from water solution to form hydrated compound APhEDPH4·3H2O (1). By introducing a base bridging ligand 4,4′-bipyridyl (4,4′-bipy), another supramolecular compound (APhEDPH3)2·(4,4′-bipyH2) (2) is obtained. Both of them were characterized by X-ray diffraction (XRD), elemental analysis (EA), infrared spectrometry (IR), thermogravimetric analysis (TGA) and single crystal X-ray diffraction. In compound 1, APhEDPH4 molecules form 2D supramolecular layers and extend to 2D sandwich type supramolecular architecture with the existence of water molecules. Whereas, compound 2 contains 2D supramolecular layers constructed by APhEDPH3- anions, and shows a three-dimensional (3D) tessellate-type supramolecular structure via the bridging effect of 4,4′-bipyH22+. Compound 2 shows intense blue photoluminescence with when excited by ultraviolet ray. The effect of bridged ligand on the dimensions of the final product is also discussed.