Photoluminescences and 1D chain-like structures with dinuclear lanthanide(III) units featuring bipyridine-tetracarboxylate

Four isostructural lanthanide(III) complexes, [Ln2(HL)2(H2O)4]n·2nH2O (H4L = 3,3′,6,6′-tetracarboxyl-2,2′-bipyridine) (Sm (1), Eu (2), Gd (3), Tb (4)), have been synthesized under the hydrothermal condition and characterized by single-crystal X-ray diffractions, powder X-ray diffractions (PXRD), thermal analyses (TGA) and elemental analyses (EA). These four complexes all exhibit 1D chain-like structures containing di-nuclear lanthanide(III) units, which are further linked by hydrogen bonding into 3D supramolecules. To further investigate the properties of the above complexes, the photoluminescent properties of 2 and 4 are also discussed.