Abstract
Three 3D lanthanide-organic frameworks (LOFs), [LnL(HCO2)(DMF)]n (Ln = Eu (1), Gd (2), Dy (3); H2L = 2,2′-dimethoxy-4,4′-biphenyldicarboxylic acid), have been prepared by the solvothermal reaction of Ln(NO3)3·6H2O and H2L in DMF-H2O mixed solvent. Crystallographic data show that LOFs 1-3 are isomorphous and crystallize in the orthorhombic space group Pna21. Each Ln(III) is eight-coordinated to four O atoms from four L2- ligands, one O atom from the DMF molecule and three O atoms from HCO2-. The adjacent Ln(III) ions are linked by the carboxylate groups of the L2- ligands and HCO2- to form a 1D inorganic rod-shaped [Ln(CO2)2(HCO2)]n chain as a secondary building unit (SBU). The infinite 1D chains are interconnected by the biphenyl groups, giving rise to a 3D framework along the c axis. LOFs 1-3 are the first neutral Ln-carboxylate/HCO2- chain-based sra-nets. 1 exhibits characteristic luminescence of Eu3+ upon 343 nm excitation. The investigation of magnetic properties shows very weak ferromagnetic interactions (J = 0.0092(3) cm-1) between Gd(III) ions in 2 with a Gd-O-Gd bridging angle of 125.6(1)°, and θ = -1.9(2) K in 3 due to thermal depopulation of the Stark levels of Dy(III) ions and/or the possible antiferromagnetic interactions between Dy(III) ions in contrast to the single-ion behavior observed in 1.
Original language | English |
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Pages (from-to) | 9281-9288 |
Number of pages | 8 |
Journal | Dalton Transactions |
Volume | 44 |
Issue number | 19 |
DOIs | |
State | Published - 21 May 2015 |