Search

Five new lanthanide supramolecular complexes, namely, [Sm(oqa){sub 2}(H{sub 2}O){sub 4}]{sub 2} (ClO{sub 4}){sub 2}.(bpy){sub 2} (1), [Ln(oqa){sub 3}].2H{sub 2}O [Ln=Sm(2), Gd(3)] and [Ln(oqa){sub 2}(NO{sub 3})(H{sub 2}O); Ln=Pr(4), Eu(5)] (oqa=4-oxo-1(4H)-quinolineacetate, bpy=4,4'-bipyridine), have been synthesized under hydrothermal conditions. These complexes exhibit three typical structure features. Complex 1 possesses a dimeric structure, which is further connected together through hydrogen bonds and pi-pi attractions, forming a 3D supramolecular framework. Compounds 2-3 are isomorphous and contain 1D ring-like chains, which are further interconnected by the oqa ligands into 2D sheet-like structures. 4 and 5 exhibit eight-connected 3D network of 4{sup 24}.6{sup 4}-bcu topology. The various coordination modes of carboxylate ligands and the selection of the counterions have clearly affected the topological structures. Furthermore, the solid-state luminescent properties of complexes 1, 2 and 5 were investigated at room temperature and they show intense, characteristic emissions in the visible region. - Graphical abstract Text7: The hydrothermal reactions of the oqa molecules with varied lanthanide ions resulted in the formation of five new complexes, which exhibit three typical structure features.

Reactions of 4-oxo-1(4H)-quinolineacetic acid (Hoqa) and varied metal salts of Zn(II), Cd(II) and Ag(I) resulted in the formation of three new coordination polymers, namely, [Zn(oqa)2]·H2O (1), [Cd(bpy)(oqa)2(H2O)2]·4H2O (2) and [Ag(bpy)(oqa)]·2H2O (3) (bpy = 4,4′-bipyridine). Complex 1 has a three-dimensional (3D) polymeric network with diamondoid topology; compounds 2–3 exhibit one-dimensional (1D) chain structure characteristics, which are further assembled through π–π stacking attractions and hydrogen bonds, forming the 3D supramolecular frameworks. In addition, the solid-state luminescent properties of the ligand Hoqa and complexes 1–2 have been investigated at room temperature.