Syntheses, structure, and properties of a series of three-dimensional lanthanide-based hybrid frameworks

A novel family of lanthanide hybrid frame works, {[Ln(2)(IDA)(3)]center dot(H2O)(2)}(n) (Ln = Nd (1), Eu (2), Tb (3), Dy(4); H(2)IDA = iminodiacetic acid), has been synthesized from the self-assembly of the lanthanide ions (Ln(3+)) with iminodiacetic acid under hydrothermal conditions and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction. Structural analyses revealed 1-4 have intricate frameworks with three-dimensional (3D) Ln-O-Lninorganic connectivity, in which the IDA(2-) ligands adopt the different mu(3)- and mu(4)- bridging forms. The 3D inorganic skeleton of the hybrid can be described as helices of corner-sharing LnN(1)O(8) polyhedra connected by edge-sharing dinuclear Ln(2)N(4)O(12) units, specified by the Schlafli symbol of 8.8.10(3) as a 82.10-a (lig) topology. The structures also show intersected lanthanide oxide ring channels occupied by guest water molecules, based on which the reversible de-/rehydration occurs. Photoluminescence measurements indicate 2 and 3 are red and green emitters, respectively, in the solid state at room temperature. Besides, the magnetic properties of 1 have been studied. (C) 2013 Elsevier B. V. All rights reserved.