Synthesis, crystal structure and fluorescent characterization of a novel lanthanide tetraphosphonate with a layered structure

• Published in: Inorganica Chimica Acta 2006-03, Vol.359 (5), p.1589-1593
• Main Authors: Ying, Shao-Ming, Zeng, Xi-Rui, Fang, Xiao-Niu, Li, Xin-Fa, Liu, Dong-sheng
• Format: Article
• Language: English
• Subjects: Crystal structure; Hydrothermal synthesis; Lanthanide phosphonates; Layered compound; Luminescent
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2005.12.023

Hydrothermal reactions of Gd(III) nitrate with N, N, N′, N′-tetramethylenephosphono-1,4-diaminobutane afforded a novel Gd(III) phosphonate, namely, Gd[(O 3PCH 2)(HO 3PCH 2)N(H)(CH 2) 4N(H)(CH 2PO 3H) 2] · 2H 2O. In this compound, the interconnection of Gd(III) ions through bridging tetraphosphonate H 5L anions lead to the formation of the 〈0 1 1〉 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 441 nm. Hydrothermal reactions of Gd(III) nitrate with N, N, N′, N′-tetramethylenephosphono-1,4-diaminobutane, (H 2O 3PCH 2) 2N–(CH 2) 4–N(CH 2PO 3H 2) 2 (H 8L), afforded a novel Gd(III) phosphonate, namely, Gd[(O 3PCH 2)(HO 3PCH 2)N(H)(CH 2) 4N(H)(CH 2PO 3H) 2] · 2H 2O, [Gd(H 5L)] · 2H 2O. Its structure was established by a single-crystal X-ray diffraction study. In this compound, the Gd(III) ion is coordinated by eight phoshonate oxygen atoms from five different phosphonate groups, which belong to five different phosphonic ligands. Each Gd atom is connected with its neighboring Gd atoms by two phosphonate oxygens, forming a gadolinium phosphonate slab along the a-axis. Such slabs are bridged by tetraphosphonate H 5L anions, resulting in a 〈0 1 1〉 layer with the butane groups toward the interlayer space. These layers are further interlinked by strong hydrogen bonds formed by uncoordinated phosphonate oxygens into a 3D supermolecular structure. Luminescent studies indicate that this compound exhibits a broad blue fluorescent emission band at 441 nm.