Syntheses, structures and fluorescence studies of two new cadmium(II) pyridyl-diphosphonates

Two new cadmium diphosphonate complexes, namely, Cd2(H2O)2[(C5H5N)CH2C(OH)(PO3)(PO3H)]2 1 and Cd2(H2O)(Cl)[(C5H5N)CH2C(OH)(PO3)2] 2, based on [1-hydroxy-2-(3-pyridyl)-ethylidene]-bis-[phosphonic acid] monosodium salt have been synthesized under hydrothermal reaction and characterized by single crystal X-ray diffraction. Both complexes show strong fluorescence emission in contrast to the free ligand, respectively, in solid state at ambient temperature.