Synthesis, crystal structures and photoluminescent properties of lanthanide supramolecular complexes with 4-oxo-1(4H)-quinolineacetate

Five new lanthanide supramolecular complexes, namely, [Sm(oqa)2(H2O)4]2 (ClO4)2·(bpy)2 (1), [Ln(oqa)3]·2H2O [Ln=Sm(2), Gd(3)] and [Ln(oqa)2(NO3)(H2O)] [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 π–π 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 424·64-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 Text7The hydrothermal reactions of the oqa molecules with varied lanthanide ions resulted in the formation of five new complexes, which exhibit three typical structure features.Figure optionsDownload full-size imageDownload as PowerPoint slide