Synthesis, Crystal Structure and Fluorescent Characterization of a Novel Lanthanide Tetraphosphonate with a Layered Structure

Hydrothermal reactions of Gd(III) nitrate with N,N,N′,N′-tetramethylenephosphono-1,4-diaminobutane afforded a novel Gd(III) phosphonate, namely, Gd[(O3PCH2)(HO3PCH2)N(H)(CH2)4N(H)(CH2PO3H)2]·2H2O. In this compound, the interconnection of Gd(III) ions through bridging tetraphosphonate H5L anions lead to the formation of the 〈011〉 Gd(III) diphosphonate 2D layer. These layers are further interlinked by strong hydrogen bonds formed by non coordinated phosphonate oxygens into a 3D supermolecular structure. Luminescent studies indicate that this compound exhibits a broad blue fluorescent emission band at 441nm.