Synthesis, structures, and luminescent properties of four new 3D lanthanide metal–organic frameworks with fluorescent whitener, 4,4′-biphenyldicarboxylate and 1,10-phenanthroline

A new series of lanthanide metal–organic frameworks, namely, [Ln (L) (bpdc)0.5 (phen)]∞ (Ln=Eu (1), Gd (2), Tb (3), Dy (4); L=4,4′-bis(2-sulfonatostyryl)biphenyl; bpdc=4,4′-biphenyldicarboxylate; phen=1,10-phenanthroline), has been synthesized hydrothermally from the self-assembly of the lanthanide ions (Ln3+) with the fluorescent whitener disodium 4,4′-bis(2-sulfonatostyryl)biphenyl (Na2L), the 4,4′-biphenyldicarboxylic acid (H2bpdc) and 1,10-phenanthroline. All of them were characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis and single-crystal X-ray diffraction. To the best of our knowledge, this is the first time to use the Na2L to synthesize LMOFs in coordination bonds binding fashion. Structural analyses reveal that all four complexes have isostructural three-dimensional (3D) net-structures. Complexes 1–4 display intriguing fluorescent properties and the photoluminescent properties of 1 were discussed in detail.