| Abstract |
In this manuscript, microwave-assisted synthesis was used to prepare a new organic building block and a Metal-Organic Framework based on this unit. The tetrapodal organic linker [1,1 -biphenyl]-3,3 ,5,5 -tetrayltetrakis(phosphonic acid) (H(8)btp) was combined with lanthanide cations affording the isotypical 2D lanthanide-organic frameworks [Ln(4)(H(6)btp)(2)(H(4)btp)(2)(H(8)btp)(H2O)(16)]center dot 12H(2)O [where Ln(3+) = La3+ (1), (La0.9Eu0.1)(3+) (2) and (La-0.9)(3+) (3)]. 1 was isolated as large single-crystals and its crystal structure was solved by single-crystal X-ray diffraction. Phase identification of the Eu3+-(2) and Tb3+-based (3) materials was performed by powder X-ray diffraction. Compound 1 consists of two-dimensional double-deck layers, characterized by an unprecedented tetranodal 2,4,4,4-connected layered network, with total point symbol \4-8(5))(2)\4(2).8(4)\\4(3).8(2).10\(4)(4\(2). Supramolecular pi-pi interactions exist both within and between layers. 1-3 were fully characterized in the solid-state by a plethora of techniques [elemental and thermogravimetric analyses, electron microscopy (SEM and EDS), FT-IR spectroscopy and solid-state NMR]. Photoluminescence properties of the optically-active mixed-lanthanide materials 2 and 3 reveal that the employed H(8-x)btp(-x) residues are better suited to sensitize Tb3+ than Eu3+, with the measured lifetimes being of 0.83 +/- 0.01 and 0.22 +/- 0.01 ms, respectively. (C) 2016 Elsevier B.V. All rights reserved. |
